Nucleic Acid Testing (NAT) for 
Human Immunodeficiency  
Virus Type 1 (HIV-1) and 
Hepatitis C Virus (HCV): 
Testing, Product Disposition, and 
Donor Deferral and Reentry 
 
 
Guidance for Industry 
 
 
 
This guidance is for immediate implementation.  
 
FDA is issuing this guidance for immediate implementation in accordance with  
21 CFR 10.115(g)(4)(i).  Submit one set of either electronic or written comments on this 
guidance at anytime.  Submit electronic comments to https://www.regulations.gov.  Submit 
written comments to the Dockets Management Staff (HFA-305), Food and Drug Administration, 
5630 Fishers Lane, Rm. 1061, Rockville, MD 20852.  You should identify all comments with 
docket number FDA-2005-D-0140. 
 
Additional copies of this guidance are available from the Office of Communication, Outreach 
and Development (OCOD), 10903 New Hampshire Ave., Bldg. 71, Rm. 3128, Silver Spring, 
MD 20993-0002, or by calling 1-800-835-4709 or 240-402-8010, or email ocod@fda.hhs.gov, or 
from the Internet at 
https://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guid
ances/default.htm. 
 
For questions on the content of this guidance, contact OCOD at the phone numbers or email 
address listed above. 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Biologics Evaluation and Research 
May 2010 
Updated December 2017  
     
Nucleic Acid Testing (NAT) for Human 
Immunodeficiency Virus Type 1 (HIV-1) and 
Hepatitis C Virus (HCV):  Testing, Product 
Disposition, and Donor Deferral and Reentry
 
 
 
Guidance for Industry
 
 
 
 
Note:  Changes have been made to update the Guidance for Industry: Nucleic Acid Testing 
(NAT) for Human Immunodeficiency Virus Type 1 (HIV-1) and Hepatitis C Virus (HCV): 
Testing, Product Disposition, and Donor Deferral and Reentry, dated May 2010, including: 
 
  Revised recommendations for reentry of donors deferred because of reactive HCV test 
results in Section V.B.  The recommendations have been revised because of the 
discontinuation of the CHIRON RIBA HCV 3.0 SIA (RIBA), that was intended for 
use as an additional, more specific test on human serum or plasma specimens found to be 
repeatedly reactive using a licensed anti-HCV screening test.  
 
  Updated the definition of Discriminatory NAT in Section II. and made corresponding 
editorial revisions to recommendations in Section IV.C. and Sections V.A and V.B. to 
reflect approval of multiplex NAT assays that directly detect HIV-1 RNA and HCV RNA 
and simultaneously detect and discriminate HIV RNA and HCV RNA.  
 
  Updated regulation citations for consistency with the current Code of Federal 
Regulations.  
 
  Updated the Background and Discussion in Section III. to include the current estimates of 
HIV-1 and HCV in blood donations and the donor screening tests licensed since 
publication of the May 2010 guidance. 
 
 
 
 
U.S. Department of Health and Human Services 
Food and Drug Administration 
Center for Biologics Evaluation and Research 
May 2010 
Updated December 2017 
 
  Contains Nonbinding Recommendations 
 
Table of Contents 
 
I.  INTRODUCTION..............................................................................................................1 
II.  DEFINITIONS ...................................................................................................................2 
III.  BACKGROUND AND DISCUSSION .............................................................................3 
A.  NAT Algorithms .....................................................................................................6 
B.  Donor Reentry ........................................................................................................7 
IV.  RECOMMENDATIONS FOR NAT ALGORITHMS .................................................10 
A.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Multiplex NAT (MP-NAT):  Resolution by 
Testing Subpools or by Testing Individual Donor Samples .............................10 
B.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Single Virus NAT (MP-NAT):  Resolution by 
Testing Subpools or by Testing Individual Donor Samples .............................15 
C.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Multiplex NAT (ID-NAT) 
after Negative Antibody Screening Tests ...........................................................19 
D.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Single Virus NAT (ID-NAT) 
after Negative Antibody Screening Tests ...........................................................23 
V.  RECOMMENDATIONS FOR DONOR REENTRY ...................................................26 
A.  Reentry for Donors Deferred Because of Reactive HIV-1/2 Test Results ......26 
B.  Reentry for Donors Deferred Because of Reactive HCV Test Results ...........33 
VI.  REFERENCES .................................................................................................................39 
 
i  Contains Nonbinding Recommendations 
 
Nucleic Acid Testing (NAT) for Human Immunodeficiency Virus 
Type 1 (HIV-1) and Hepatitis C Virus (HCV):  Testing, Product 
Disposition, and Donor Deferral and Reentry 
 
 
Guidance for Industry 
 
 
This guidance represents the current thinking of the Food and Drug Administration (FDA or 
Agency) on this topic.  It does not establish any rights for any person and is not binding on FDA 
or the public.  You can use an alternative approach if it satisfies the requirements of the 
applicable statutes and regulations.  To discuss an alternative approach, contact the FDA staff 
responsible for this guidance as listed on the title page. 
 
 
I.  INTRODUCTION 
 
We, the Food and Drug Administration (FDA), are providing recommendations to you, blood 
and plasma establishments, manufacturers, and testing laboratories for testing individual samples 
or pooled samples from donors of human blood and blood components for Human 
Immunodeficiency Virus Type 1 (HIV-1) ribonucleic acid (RNA) and Hepatitis C Virus (HCV) 
RNA using the Nucleic Acid Test (NAT).  This guidance also contains recommendations 
regarding product disposition and donor management based on the results of NAT testing for 
markers of HIV-1 and HCV infection on samples, collected at the time of donation, from donors 
of human blood and blood components. 
 
This guidance amends the guidance entitled, Nucleic Acid Testing (NAT) for Human 
Immunodeficiency Virus Type 1 (HIV-1) and Hepatitis C Virus (HCV):  Testing, Product 
Disposition, and Donor Deferral and Reentry dated May 2010 (75 FR 22814).  The May 2010 
guidance finalized the draft guidance of the same title, dated July 2005 and also superseded the 
recommendations for reentry of donors deferred because of anti-HIV-1 test results, HIV-1 p24 
antigen test results, and anti-HCV test results that were provided in the FDA memoranda 
entitled, Revised Recommendations for the Prevention of Human Immunodeficiency Virus 
(HIV-1) Transmission by Blood and Blood Products April 23, 1992; Revised 
Recommendations for Testing Whole Blood, Blood Components, Source Plasma and Source 
Leukocytes for Antibody to Hepatitis C Virus Encoded Antigen (Anti-HCV) August 5, 1993; 
Recommendations for Donor Screening with a Licensed Test for HIV-1 Antigen August 8, 
1995 (Refs. 1 through 3). 
 
FDAs guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the FDAs current thinking on a topic and should be 
viewed only as recommendations, unless specific regulatory or statutory requirements are cited.  
The use of the word should in FDA guidances means that something is suggested or 
recommended, but not required. 
1  Contains Nonbinding Recommendations 
 
 
 
II.  DEFINITIONS 
 
Anti-HIV-1 or -2 Test or Anti-HIV-1/2 Test or Anti-HCV Test:  A screening test, such as an 
enzyme immunoassay, performed on donations of blood and blood components, that FDA has 
licensed, approved or cleared for such use (hereinafter referred to as licensed). 
 
Deconstruction:  Resolution of the reactivity of a minipool by testing subpools (original or 
freshly made) or samples from individual donors that formed the minipool.  Deconstruction of a 
reactive minipool to individual units is a required step for all approved tests.1 
 
Discriminatory NAT:  A NAT that uses specific primers for HIV-1 or HCV to identify the 
RNA in a reactive multiplex NAT sample that might contain either HIV-1 RNA or HCV RNA 
based on the assay.  Performing a Discriminatory NAT assay on a reactive sample is a required 
step for those establishments using certain multiplex tests that do not simultaneously detect and 
discriminate HIV RNA and HCV RNA in the same reaction.2 
 
Donor Reentry:  A procedure that qualifies a deferred donor as eligible to donate again.  Donor 
reentry procedures may be used following a false positive test result and typically require the 
passage of time to allow for possible seroconversion prior to the performance of additional 
serologic testing and NAT (see sections V.A. and V.B. of this document). 
 
Lookback:  A series of actions taken by a blood establishment based on donor test results 
indicating infection with HIV-1 or HCV.  These actions relate to the donors prior donations that 
possibly were donated during the window period when HIV-1 or HCV RNA and antibody were 
not detectable by screening tests but the infectious agent might be present in the donors blood.  
These actions include:  quarantining the remaining inventory of prior collections from that donor, 
notifying consignees to quarantine prior collections, further testing of the donor, destroying or 
re-labeling potentially infectious prior collections, and when appropriate, notifying transfusion 
recipients who received human blood or blood components from that donor. 
 
Minipool:  A pool of donor samples on which NAT (minipool NAT or MP-NAT) is performed 
as a screening test.  A minipool is formed by pooling of samples from subpools or by directly 
pooling samples from individual donors. 
 
Multiplex NAT:  A NAT that simultaneously detects HIV-1 RNA and HCV RNA. 
 
Single Virus NAT:  A NAT that separately detects either HIV-1 RNA or HCV RNA. 
 
Subpool:  A pool of donor samples that was used with other (sub)pools to form the minipool or 
that was formed as a result of deconstruction of the minipool. 
 
                                                 
1 Under Title 21 of the Code of Federal Regulations (CFR) 610.40(b) (21 CFR 610.40(b)), you must use screening 
tests that FDA has licensed, approved, or cleared for such use, in accordance with the manufacturers instructions. 
2 Id. 
2  Contains Nonbinding Recommendations 
 
 
III.  BACKGROUND AND DISCUSSION 
 
FDA has progressively strengthened the overlapping safeguards that protect patients from 
unsuitable blood and blood products.  Blood donors are now asked specific and very direct 
questions about risk factors that could indicate possible infection with a transmissible disease.  
This up-front screening eliminates approximately 90 percent of ineligible donors.  In addition, 
FDA requires blood centers to maintain lists of deferred donors to prevent the use of collections 
from them. 
 
During the past decade blood establishments have implemented new donor screening tests, 
including sensitive tests for viral antibody, antigen (for HIV-1), and nucleic acids, and there has 
been a dramatic reduction in the transmission of HIV-1 and HCV by human blood and blood 
components.  Sources of remaining risk for HIV-1 and HCV transmission by human blood 
products include:  1) marker-negative window period donations (made during the period that 
the donor is infected with a virus, but neither the virus nor antibodies to the virus are detectable 
by current tests); 2) donors infected with genetic and immunovariant viral strains; 3) persistent 
antibody-negative (immunosilent) carriers; and 4) laboratory errors.  According to a recent 
report, donations during the window period constitute most of the risk of HIV-1 and HCV 
transmission (Ref. 4).  Therefore, measures to reduce the window period might further reduce the 
residual risk of HIV-1 and HCV transmission by human blood and blood components. 
 
Studies performed using seroconversion panels indicate the value of NAT in reducing the 
window period for HIV-1 and HCV.  The estimated mean window-period reduction for HIV-1 
RNA by pooled sample NAT is approximately 11 to 15 days relative to antibody testing and 5 to 
9 days relative to HIV-1 p24 antigen testing (Refs. 5 through 7).  NAT for detection of HCV has 
been estimated to reduce the window period by 50 to 60 days relative to that for HCV antibody.  
During a ten-year period (1999-2008), approximately 66 million donations were screened with 
32 HIV (1:2 million) and 244 HCV (1:270,000) NAT yield (RNA-positive but antibody-
negative) donations identified (Ref. 6).  Subsequent to implementation of NAT, the residual risk 
of HIV-1 and HCV in screened human blood and blood component donations in 2007-2008 was 
estimated to be approximately 1 in 1,467,000 donations for HIV-1 and 1 in 1,149,000 donations 
for HCV (Ref. 6). 
 
In September 1994, we held a workshop to discuss the potential application of nucleic acid based 
methods to donor screening for HIV-1.  We concluded at the time that these methods clearly 
were sensitive, but they were not ready for implementation on a large scale. 
 
The industry actively pursued the development of NAT for screening donors of human blood and 
blood components.  There was much interest in testing pools of plasma donor samples 
(minipools) by NAT because of the cost and labor intensiveness of testing individual donor 
samples.  By 1997, some manufacturers in Europe had voluntarily instituted NAT on minipools.  
In 1998, the European Union issued a directive that by July 1, 1999, HCV RNA testing would be 
required in Europe for all plasma for fractionation and that the requirement for HIV-1 RNA 
testing would follow at a later date. 
 
3  Contains Nonbinding Recommendations 
 
Large-scale clinical studies were needed to demonstrate the efficacy of NAT because of the 
expected low frequency of window period donations.  Test kit manufacturers and testing 
laboratories submitted Investigational New Drug applications (INDs) describing their test 
method and in-house validation of that method.  Blood organizations and establishments 
intending to use the assay for donor screening also filed INDs to describe their clinical trial 
protocol for validation of pooled-donor sample NAT (MP-NAT) and individual donor sample 
NAT (ID-NAT). 
 
In December 1999, we issued a guidance for industry on the validation of NAT methods to 
screen plasma donors (Ref. 8).  This document provided guidance on test standards, 
manufacturing requirements, and clinical trial requirements for licensure of the test method for 
use in donor screening for transfusion-transmitted viruses. 
 
In September 2001, we licensed the first NAT system, the National Genetics Institute (NGI) 
UltraQual HIV-1 and HCV Reverse Transcription Polymerase Chain Reaction (RT-PCR) assays.  
Under that license, NGI performs RT-PCR assays on pooled samples from donors of Source 
Plasma. 
 
In February 2002, we licensed the Procleix HIV-1/HCV Assay, a qualitative NAT for detection 
of HIV-1 RNA and/or HCV RNA in plasma from donors of human blood and blood components 
for transfusion.  This assay was approved for use with individual donor samples or pooled donor 
samples. 
 
In December 2002, we licensed the COBAS AmpliScreen HCV Test, v 2.0 and the COBAS 
AmpliScreen HIV-1 Test, v 1.5.  These tests are qualitative in vitro tests for the direct detection 
of HCV RNA and HIV-1 RNA in plasma samples from human donors, including donors of 
Whole Blood, blood components, and Source Plasma, and from other living donors.  These 
assays were approved for use with individual donor samples or pooled donor samples. 
 
In October 2004, we issued a final guidance, Use of Nucleic Acid Tests on Pooled and 
Individual Samples from Donors of Whole Blood and Blood Components (including Source 
Plasma and Source Leukocytes) to Adequately and Appropriately Reduce the Risk of 
Transmission of HIV-1 and HCV dated October 2004 (October 2004 guidance).  That guidance 
combined and finalized the draft guidance Use of Nucleic Acid Tests on Pooled Samples from 
Source Plasma Donors to Adequately and Appropriately Reduce the Risk of Transmission of 
HIV-1 and HCV dated December 2001, and the draft guidance Use of Nucleic Acid Tests on 
Pooled and Individual Samples from Donors of Whole Blood and Blood Components for 
Transfusion to Adequately and Appropriately Reduce the Risk of Transmission of HIV-1 and 
HCV dated March 2002. 
 
The October 2004 guidance informed establishments collecting blood and blood components that 
we have licensed NAT to screen blood donors for HIV-1 RNA and HCV RNA and that these 
licensed tests could detect evidence of infection at a significantly earlier stage than is possible 
under previously approved tests using antibody or antigen detection technology, including the 
HIV-1 p24 antigen test.  We also informed those establishments that we believe these newly    
4  Contains Nonbinding Recommendations 
 
licensed tests are now widely available and meet the criteria in 21 CFR 610.40(b) for screening 
tests that are necessary to reduce adequately and appropriately the risk of transmission of 
communicable disease through blood and blood products. 
 
In the October 2004 guidance, we recommended the use of HIV-1 NAT and HCV NAT on units 
that are not reactive on a donor-screening test for the detection of antibodies to HIV-1 or HCV, 
respectively.  However, for donations that are reactive on a test for the detection of antibodies to 
HIV-1 or HCV and are to be discarded or used in the manufacture of non-injectable products, we 
do not consider HIV-1 NAT and HCV NAT to be necessary as part of the adequate and 
appropriate testing required under 21 CFR 610.40(b).  We informed the establishments that even 
though testing for these products is not required under 21 CFR 610.40(b), they may decide to 
perform HIV-1 NAT and HCV NAT for these donations in order to obtain useful information 
regarding the donors infection status.  This information might be useful as part of donor 
notification. 
 
In October 2006, we licensed the Procleix Ultrio Assay, a qualitative in vitro assay system to 
screen for HIV-1 RNA and HCV RNA in plasma and serum specimens from human donors, 
including donors of Whole Blood, blood components, and Source Plasma, and from other living 
donors.  This assay was also approved for use with individual donor samples or pooled donor 
samples. 
 
In February 2007, we licensed the BioLife Plasma Services HIQ-PCR HIV-1 RT-PCR assay and 
the HIQ-PCR HCV RT-PCR assay for the qualitative detection of HIV-1 RNA and HCV RNA, 
respectively, in pools of human Source Plasma. 
 
In December 2008, we licensed the cobas TaqScreen MPX Test, a qualitative in vitro screening 
test for individual human donors, including donors of Whole Blood and blood components, and 
other living donors, for the presence of HIV-1 Group M RNA, HCV RNA, and Hepatitis B Virus 
(HBV) DNA.  Plasma from all donors may be screened as individual specimens.  For donations 
of Whole Blood and blood components, plasma specimens may be tested individually or in 
pools. 
 
In May 2012, we licensed the Gen-Probe Procleix Ultrio Plus Assay, a qualitative in vitro test for 
use on the Procleix TIGRIS System to screen for HIV-1 RNA, HCV RNA and HBV DNA in 
plasma and serum specimens from individual human donors, including donors of whole blood, 
blood components, and source plasma, and from other living donors.  This assay was also 
approved for use with individual donor samples or pooled donor samples. 
 
In December 2014, we licensed the cobas TaqScreen MPX Test, version 2.0, for use the cobas s 
201 system, a qualitative in vitro screening test for the direct detection of HIV-1 Group M RNA, 
HIV-1 Group O RNA, HIV-2 RNA, HCV RNA and HBV DNA in plasma specimens from 
individual human donors, including donors of Whole Blood, blood components, Source Plasma 
and other living donors.  Plasma specimens may be tested individually or in pools. For an 
individual specimen, results are simultaneously detected and discriminated for HIV, HCV, and 
HBV. 
 
5  Contains Nonbinding Recommendations 
 
In October 2016, we licensed the cobas MPX Test, for use on the cobas 6800/8800 Systems, a 
qualitative in vitro test screening test for the direct detection of HIV-1 Group M RNA, HIV-1 
Group O RNA, HIV-2 RNA, HCV RNA, and HBV DNA in human plasma and serum.  The 
cobas MPX Test simultaneously detects and discriminates for HIV, HCV and HBV and does not 
discriminate between HIV-1 Group M, HIV-1 Group O, and HIV-2.  
 
This guidance is intended to assist you with testing, product disposition, donor deferral, donor 
notification, donor reentry, and lookback.  We have written this document in general form 
because other NAT may be approved in the future.  However, where appropriate, we will 
identify sections that apply to NAT that are already approved.  You must follow manufacturers 
instructions regarding testing under 21 CFR 610.40(b). 
 
A.  NAT Algorithms 
 
Under 21 CFR 610.40(b), you must use screening tests that FDA has licensed, approved, 
or cleared for such use, in accordance with the manufacturers instructions.  If you 
perform NAT on pooled samples and obtain a reactive NAT result on a minipool, the 
manufacturers instructions instruct you to perform subsequent testing to identify the 
individual unit(s) that contains the RNA identified in the minipool test.  Once you have 
identified a positive unit, either by subsequent testing of a minipool or by initial 
individual donor sample testing, you must not use the donation for transfusion or for 
manufacturing into injectable products (21 CFR 610.40(h)(1)) unless an exception 
applies (21 CFR 610.40(h)(2)).  You must defer the donor (21 CFR 610.41(a)), and you 
must inform the donor of the deferral and the reason for the deferral, including test results 
if they were the basis for the deferral (21 CFR 630.40).  You must also perform 
lookback to identify blood products previously donated (21 CFR 610.46 and 610.47).  
A reactive NAT result may indicate ongoing infection of the donor.  Thus, prior 
donations from that donor, although NAT-non-reactive, may pose a risk to transfusion 
recipients. 
 
In the FEDERAL REGISTER of August 24, 2007 (72 FR 48765), FDA published the 
final rule entitled Current Good Manufacturing Practice for Blood and Blood 
Components; Notification of Consignees and Transfusion Recipients Receiving Blood 
and Blood Components at Increased Risk of Transmitting Hepatitis C Virus Infection 
(Lookback) (Lookback rule) (Ref. 9).  The Lookback rule established lookback 
requirements related to HCV infection and revised the requirements related to HIV 
infection.  It requires that you perform lookback for HIV-1 and for HCV when donor 
samples test reactive using HIV-1 NAT or HCV NAT.  Donors infected with HIV-1 or 
HCV may experience intermittent viremias for a variable period of time prior to a 
persistently detectable viremia or an antibody response.  Since these episodes of transient 
viremia may extend over a longer window period than previously estimated, the 
Lookback rule requires you to review all records for a period of 12 months before the 
donors reactive NAT.  A 12-month timeframe is necessary to encompass with sufficient 
confidence the window period for HIV-1 or for HCV prior to the detection of antibody.   
   
6  Contains Nonbinding Recommendations 
 
We have not established an alternative (possibly shorter than 12 months) lookback period 
based on the last non-reactive NAT, in order to minimize operational complexity and 
because the appropriate period has not been well established scientifically. 
 
At the meeting of the Blood Products Advisory Committee (BPAC) in March 20013, 
FDA requested advice on appropriate algorithms for management of donations of human 
blood and blood components tested by pooled donor sample NAT for both HIV-1 RNA 
and HCV RNA.  In particular, FDA sought comment on actions to be taken in the event 
of discrepant testing results, such as when the minipool is reactive but individual donor 
samples test non-reactive.  Data generated using NAT under IND that was presented in 
the BPAC meeting showed that in each discrepant case it was the minipool that was 
falsely reactive, due to contamination either during specimen handling or during the 
assay run.  In response to FDA questions the BPAC voted to consider the NAT result on 
samples from individual donors as the definitive test result, and recommended release 
from quarantine for donations from those donors, on the basis of non-reactive individual 
test results. 
 
This guidance contains four recommended algorithms for use when NAT-reactive results 
are obtained on individual samples or pooled samples from donors of human blood and 
blood components.  Note that these algorithms apply when only the HIV-1 NAT or HCV 
NAT result is reactive (i.e., serologic tests for HIV-1/2 and HCV are negative).  This 
guidance also contains recommendations on product disposition, donor deferral criteria, 
follow-up testing of the donor, donor notification, and lookback (product retrieval and 
recipient notification).  This guidance is not intended to replace manufacturers 
instructions for testing using approved tests. 
 
The first and second algorithms (see sections IV.A. and IV.B, Figures 1 and 2, and Tables 
1 and 2 of this document) recommend actions to deconstruct a reactive minipool by 
testing archived or freshly pooled subpools or by testing individual donor samples.  The 
third and fourth algorithms (see sections IV.C. and IV.D, Figures 3 and 4, and Tables 3 
and 4 of this document) recommend actions to be taken when a NAT-reactive result is 
obtained on an individual sample from a donor of human blood or blood components. 
 
B.  Donor Reentry 
 
Each year many donors are deferred from donating blood for an indefinite period because 
of a false positive test result on a serologic test, followed by a negative or indeterminate 
supplemental test for antibodies to HIV-1 or HCV.  In addition to these deferrals the 
implementation of NAT for HIV-1 RNA and HCV RNA has resulted in additional 
deferrals of donors each year due to potentially false reactive NAT results. 
 
These deferred donors may be eligible to be considered for reentry to donate blood or 
blood components.  Under 21 CFR 610.41(b), a deferred donor subsequently may be 
found to be eligible as a donor by a re-qualification method or process found acceptable 
                                                 
3 https://wayback.archive-
it.org/7993/20170403222320/https://www.fda.gov/ohrms/dockets/ac/cber01.htm#Blood%20Products 
7  Contains Nonbinding Recommendations 
 
for such purposes by FDA.  However, some establishments are not attempting to reenter 
donors because of the complexity of the current reentry algorithms and concerns about 
inappropriately reentering a donor.  Although we do not require reentry of donors 
deferred because of false positive test results, we issued guidance in April 1992 on 
reentry of donors deferred because of a repeatedly reactive (RR) test for antibodies to 
HIV-1 or HIV-2, and in August 1993 on reentry of donors deferred because of a RR test 
for antibodies to HCV (Refs. 1 and 3). 
 
This guidance contains recommendations for reentry of donors deferred because of 
reactive HIV-1 NAT or HCV NAT or certain other test results in accordance with  
21 CFR 610.41(a).  We find these reentry methods to be acceptable within the meaning 
of 21 CFR 610.41(b).  Note that the reentry of a donor permits prospective donations 
from a reentered donor who meets donor eligibility criteria.  It does not affect the status 
of previous collections from that donor, including donations subject to lookback. 
 
Reentry of Donors (HIV Test Results) 
 
In this guidance, we recommend that you consider for reentry three groups of donors 
deferred because of reactive HIV-1 NAT or RR anti-HIV-1 or -2 test or RR anti-HIV-1/2 
test or RR HIV-1 p24 antigen test results (see section V.A., Figure 5, and Table 5 of this 
document).  These three groups of donors include: 
 
1.  Donors with a reactive HIV-1 NAT result but who were seronegative for 
antibodies to HIV-1 and HIV-2; 
  
2.  Donors with non-reactive HIV-1 NAT (or NAT was not performed) who had a 
RR anti-HIV-1/2 test and an HIV-1 Western Blot (WB) or immunofluorescence 
assay (IFA) that was indeterminate (viral bands may be present), unreadable, 
negative, or was not performed; and 
  
3.  Donors with a positive or indeterminate result on the HIV-1 p24 Neutralization 
test (Ref. 2), even on more than one occasion.  This last group of donors may be 
eligible for reentry because there are many donors who had (false) positive 
Neutralization test results who are currently non-reactive by HIV-1 NAT and 
negative by an anti-HIV-1 or anti-HIV-1/2 test. 
 
FDA no longer recommends that blood and plasma establishments using certain approved 
NAT methods perform screening for HIV-1 p24 antigen.  If antigen testing continues to 
be performed concurrent with NAT and antibody testing, donors deferred because of 
HIV-1 p24 test results would continue to be eligible for reentry. 
 
Data presented at the June 2001 BPAC meeting demonstrated that an 8-week waiting 
period encompasses the pre-seroconversion window period for HIV-1 with sufficient 
confidence that negative tests, after at least 8 weeks have passed, rule out HIV-1 infection  
   
8  Contains Nonbinding Recommendations 
 
(Ref. 10).  Absent evidence for seroconversion, a negative NAT on follow-up testing 
provides evidence that the prior reactive (but unconfirmed) NAT result was likely an 
error. 
 
Accordingly, for all three groups of donors, after a minimum time period of 8 weeks we 
recommend that you take a follow-up sample from the donor for testing by both HIV-1 
ID-NAT and an anti-HIV-1/2 test.  Performing follow-up testing first on a new sample 
from the donor, collected before another donation, may prevent a potentially 
contaminated unit from being collected and placed in inventory at the blood 
establishment.  If the ID-NAT is non-reactive and the anti-HIV-1/2 test is negative on the 
follow-up sample, the donor may be reentered.  The donor would then be tested again at 
the time of his/her next donation using the battery of screening tests required under  
21 CFR 610.40.  That donation may be tested by NAT as part of a minipool (i.e., MP-
NAT) or as an individual donation (i.e., ID-NAT).  Thus, two HIV-1 NAT tests would be 
performed and must be non-reactive and two anti-HIV-1/2 tests would be performed and 
must be negative before a unit from that donor could be used.  For purposes of donor 
counseling, you may choose to test the deferred donor with an HIV-1 NAT and an anti-
HIV-1/2 test at any time prior to the end of this 8-week waiting period after the original 
donation.  However, if an HIV-1 NAT is reactive prior to the end of this 8-week waiting 
period, the donor would not be eligible for reentry and we recommend that you defer the 
donor permanently.  If an anti-HIV-1/2 test is RR prior to the end of this 8-week waiting 
period, and a licensed supplemental test for antibodies to HIV-1 (i.e., WB or IFA), if 
performed, is not positive, you may take another follow-up sample from the donor for 
testing by both HIV-1 ID-NAT and an anti-HIV-1/2 test after another 8-week waiting 
period has passed. 
 
Reentry of Donors (HCV Test Results) 
 
In this guidance, we recommend that you consider for reentry two groups of donors 
deferred because of reactive HCV NAT or RR anti-HCV test results (see section V.B., 
Figure 6, and Table 6 of this document).  These two groups of donors include: 
 
1.  Donors with a reactive HCV NAT result but who were seronegative for antibodies 
to HCV; and 
 
2.  Donors with a non-reactive HCV NAT result (or NAT was not performed) who 
had RR anti-HCV test results4.  This group includes donors who were RR on a 
second, different licensed screening test for HCV antibody, if it was used in 
further testing of the index donation.  
 
Data presented at the June 2001 BPAC meeting demonstrated that a 6-month follow-up 
period encompasses the pre-seroconversion window period with sufficient confidence 
that negative tests after at least 6 months have passed rule out HCV infection (Ref. 10). 
 
                                                 
4 This group includes deferred donors with an historical HCV RIBA that was indeterminate, negative or was not 
performed.  
9  Contains Nonbinding Recommendations 
 
For purposes of reentering both of these groups of deferred donors we recommend that 
you take a follow-up sample from the donor after a minimum period of 6 months from 
the original donation for testing by an HCV ID-NAT and two different, licensed anti-
HCV screening tests.  Current scientific data indicate that detectable viremia may be 
intermittent or may be resolved in about 15-25% of cases of HCV infection (Refs. 11 and 
12).  If the ID-NAT is non-reactive and both anti-HCV tests are negative on the follow-
up sample, the donor may be reentered.  The donor would then be tested again at the time 
of his/her next donation using the battery of screening tests required under  
21 CFR 610.40(b).  That donation may be tested by NAT as part of a minipool (i.e., MP-
NAT) or as an individual donation (i.e., ID-NAT).  Thus, two HCV NAT tests would be 
performed and must be non-reactive and three anti-HCV tests would be performed and 
must be negative before a unit from that donor could be used. 
 
If the ID-NAT is non-reactive and both of the licensed anti-HCV tests are RR after a 6-
month waiting period, we recommend that you defer the donor permanently. 
 
For purposes of donor counseling and to detect possible HCV viremia, you may also 
choose to test the deferred donor with an HCV NAT and two different, licensed anti-
HCV screening tests at any time prior to the completion of this 6-month period after the 
original donation.  If an HCV NAT is reactive prior to the end of this 6-month period, the 
donor would not be eligible for reentry and we recommend that you defer the donor 
permanently.  If an HCV NAT is non-reactive and one anti-HCV test is RR prior to the 
end of the 6-month period, you may take one more follow-up sample from the donor for 
testing by HCV ID-NAT and two different, licensed anti-HCV screening tests after a 
second 6-month waiting period.  If an anti-HCV test is still RR on a second follow-up 
sample at any time after the original donation, we recommend that you defer the donor 
permanently.  
 
 
IV.  RECOMMENDATIONS FOR NAT ALGORITHMS 
 
As discussed in sections A and B below, currently approved tests on minipools of donor samples 
for HIV-1 RNA and HCV RNA may be either Multiplex NAT for the simultaneous detection of 
HIV-1 RNA and HCV RNA or Single Virus NATs conducted separately for the RNA of the two 
viruses. 
 
A.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Multiplex NAT (MP-NAT):  Resolution by 
Testing Subpools or by Testing Individual Donor Samples 
 
If you obtain a reactive Multiplex HIV-1 RNA/HCV RNA NAT result for a minipool, the 
test instructions for use instruct you to perform subsequent testing to identify the donor 
sample(s) that are NAT-reactive as the basis for the NAT-reactive result on the pool.  In  
   
10  Contains Nonbinding Recommendations 
 
general, the manufacturers instructions for a licensed NAT describe two methods for 
resolving a minipool that is reactive on a Multiplex NAT, and you must follow the 
instructions in the package insert that provide specific testing algorithms  
(21 CFR 610.40(b)). 
 
METHOD 1:  Deconstruction of the NAT-reactive minipool may be performed by testing 
the subpools (original or freshly made) that formed the minipool.  This deconstruction of 
the minipool to identify the donor sample(s) that are NAT-reactive as the basis for the 
NAT-reactive result on the pool may involve several layers of testing using original or 
freshly pooled subpools, followed by testing of individual donor samples in the reactive 
subpool(s) (see Figure 1 and Table 1 below).   
 
1.  If you test subpools that were used to construct a Multiplex NAT-reactive 
minipool, in accordance with the manufacturers instructions you must test the 
original subpools or freshly pooled subpools using the same Multiplex NAT method 
that was used in the original NAT on the minipool (21 CFR 610.40(b)). 
 
NOTE:  In some cases the manufacturers instructions provide for a different sample 
preparation procedure.  However, the primers and probes would be the same as those 
used in the original NAT on the minipool. 
 
a.  If all subpools are non-reactive, we recommend that you release from 
quarantine all individual donations that comprise the non-reactive subpools, 
provided that serologic tests on those donor samples are negative and the 
donations are otherwise suitable for release.   
 
NOTE:  Laboratory control procedures must make adequate provisions for 
monitoring the reliability, accuracy, precision, and performance of laboratory 
test procedures and instruments (21 CFR 606.140(b)).  This includes 
monitoring the frequency of reactive minipools that, upon deconstruction, 
remain unresolved.  Laboratory control procedures must also include adequate 
identification and handling of all test samples (21 CFR 606.140(c)).  Use of 
supplies and reagents must be in a manner consistent with the instructions 
provided by the manufacturer (21 CFR 606.65(e), 21 CFR 610.40(b)).  You 
must conduct and record a thorough investigation including the conclusions 
and followup, of any unexplained discrepancy (21 CFR 606.100(c)), such as 
when the frequency of unresolved reactive minipools exceeds the threshold 
defined in your laboratory control procedures, or when there are indications of 
possible laboratory contamination of negative donor samples with positive 
samples.  This investigation must include a determination of the cause of the 
initial reactivity of the unresolved minipool.   
 
b.  If one or more of the subpools are reactive, we recommend that you 
release from quarantine the individual donations that comprise the non-
reactive subpools, provided that serologic tests on those donor samples are 
negative and the donations are otherwise suitable for release.  Consistent with 
11  Contains Nonbinding Recommendations 
 
the manufacturers instructions, you must test the individual donor samples 
that comprise the reactive subpool(s) using the same Multiplex NAT method 
that was used in the original NAT on the minipool (21 CFR 610.40(b)). 
 
(1) If all individual donor samples are non-reactive, we recommend 
that you release from quarantine all individual donations (if serologic 
tests on those donor samples are negative and the donations are 
otherwise suitable for release).  See the NOTE in section IV.A.1.a. of 
this document on laboratory control procedures and the possible need 
to conduct additional analyses to determine the cause of the initial 
reactivity of the unresolved minipool.  
 
(2) If one or more individual donor sample(s) are reactive, perform the 
steps in section IV.C.1. of this document (including testing using 
Discriminatory NAT when necessary, product disposition, donor 
management, and lookback). 
 
We recommend that you release from quarantine all non-reactive individual 
donations provided that serologic tests on those donor samples are negative 
and the donations are otherwise suitable for release. 
 
METHOD 2:  For comparatively small minipools, for example, minipools that consist of 
up to 24 individual samples, deconstruction of the NAT-reactive minipool may be 
performed by directly testing the individual donor samples that formed the minipool (see 
Figure 1 and Table 1 below).   
 
2.  If you directly test the samples from individual donors that constituted the 
Multiplex NAT-reactive minipool, in accordance with the manufacturers instructions 
you must test the individual donor samples using the same Multiplex NAT method 
that was used in the original NAT on the minipool (21 CFR 610.40(b)). 
 
NOTE:  In some cases the manufacturers instructions provide for a different sample 
preparation procedure.  However, the primers and probes would be the same as those 
used in the original NAT on the minipool. 
 
a.  If all individual donor samples are non-reactive, we recommend that you 
perform the steps in section IV.A.1.b.(1) of this document. 
 
b.  If one or more individual donor sample(s) are reactive, perform the steps in 
section IV.C.1. of this document (including testing using Discriminatory NAT 
when necessary, product disposition, donor management, and lookback). 
 
We recommend that you release from quarantine all non-reactive individual donations 
provided that serologic tests on those donor samples are negative and the donations 
are otherwise suitable for release. 
12  Contains Nonbinding Recommendations 
 
FIGURE 1.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Multiplex NAT (MP-NAT):  Resolution by Testing Subpools 
or by Testing Individual Donor Samples 
 
Minipool Reactive on a Multiplex HIV-1/HCV MP-NAT 
 
                                                     METHOD 1                 METHOD 2 
 
         TEST SUBPOOLS1`  
USING SAME MULTIPLEX  
           NAT METHOD2 
 
                                                           
                                          Non-Reactive    
                                             Subpools                                             
 
 
                                                                          
       Reactive                      RELEASE3         
     Subpool(s)                   ALL UNITS 
                               
 
                                                        TEST INDIVIDUAL DONOR SAMPLES                      
                                                    USING SAME MULTIPLEX NAT METHOD2                                         
 
                                                       
                                                                            
                                                                  
                                                                             Reactive              Non-Reactive 
                                                                    Donor Sample(s)        Donor Samples 
                                                                                                                                                
                                                         
  
                                                                                                                                       R   ELEASE3 
     
ALL UNITS 
  
 
PERFORM THE STEPS IN FIGURE 3 FOR TESTING USING DISCRIMINATORY NAT, 
PRODUCT DISPOSITION, DONOR MANAGEMENT, AND LOOKBACK 
 
 
 
1 Several layers of deconstruction using original or freshly pooled subpools, may be needed. 
2 In some cases a different sample preparation procedure may be used per manufacturers instructions.  
However, primers and probes should be same as those used in the NAT on the minipool. 
3 Units may be released only if serologic tests for HIV-1 and HCV are negative and the units are otherwise 
suitable for release. 
13  Contains Nonbinding Recommendations 
 
TABLE 1.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Multiplex NAT (MP-NAT):  Resolution by Testing Subpools 
or by Testing Individual Donor Samples 
 
 
If:  Then:  After that if:   Then:  After that if:   Then: 
           
Minipool  METHOD 1:  Reactive  Test the   Reactive donor  Perform the 
Reactive on  Test  subpool(s)  individual   sample(s)  steps in Table 3 
a  subpools1    donor samples    for testing 
Multiplex   using same    using same    (discriminatory 
HIV-1/HCV   Multiplex    Multiplex NAT    NAT), product 
MP-NAT  NAT method2    method2    disposition, 
        donor manage- 
        ment, lookback  
         
       Non-reactive  Release3  
       donor samples  all units 
         
  Non-reactive   Release3 all   
 
   subpool(s)  units 
 
   
OR 
   
 
Reactive donor  Perform the 
 
 sample(s)  steps in Table 3 
 
  for testing 
METHOD 2: 
  (discriminatory 
Test the  
  NAT), product 
individual 
  disposition, 
donor 
  donor 
samples using 
  management, 
same 
  lookback 
Multiplex 
   
NAT method2  
  Non-reactive  Release3  
   donor samples  all units 
   
1 Several layers of deconstruction using original or freshly pooled subpools may be needed. 
2 In some cases a different sample preparation procedure may be used per manufacturers instructions.  However, 
primers and probes should be same as those used in the NAT on the minipool. 
3 Units may be released only if serologic tests for HIV-1 and HCV are negative and the units are otherwise suitable for 
release. 
14  Contains Nonbinding Recommendations 
 
B.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Single Virus NAT (MP-NAT):  Resolution by 
Testing Subpools or by Testing Individual Donor Samples 
 
If you obtain a reactive result for a NAT for HIV-1 RNA and/or HCV RNA performed 
separately on a minipool, the test instructions for use instruct you to perform subsequent 
testing to identify the donor sample(s) that are NAT-reactive as the basis for the NAT-
reactive result on the pool.  In general, the manufacturers instructions for a licensed 
NAT describe two methods for resolving a minipool that is reactive on a Single Virus 
NAT, and you must follow the instructions in the package insert that provide specific 
testing algorithms (21 CFR 610.40(b)). 
 
METHOD 1:  Deconstruction of the NAT-reactive minipool may be performed by testing 
the subpools (original or freshly made) that formed the minipool.  This deconstruction of 
the minipool to identify the donor sample(s) that are NAT-reactive as the basis for the 
NAT-reactive result on the pool, may involve several layers of testing using original or 
freshly pooled subpools, followed by testing of individual donor samples in the reactive 
subpool(s) (see Figure 2 and Table 2). 
 
1.  If you test subpools that were used to construct a NAT-reactive minipool, in 
accordance with the manufacturers instructions you must test the original 
subpools or freshly pooled subpools using the same Single Virus NAT method 
that was used in the original NAT on the minipool (21 CFR 610.40(b)). 
 
NOTE:  In some cases the manufacturer's instructions provide for a different 
sample preparation procedure.  However, the primers and probes would be the 
same as those used in the original NAT on the minipool. 
 
a.  If all subpools are non-reactive, we recommend that you release from 
quarantine all individual donations that comprise the non-reactive 
subpools provided that serologic tests on those donor samples are negative 
and the donations are otherwise suitable for release.  See the NOTE in 
section IV.A.1.a. on laboratory control procedures and the possible need to 
conduct additional analyses to determine the cause of the initial reactivity 
of the unresolved minipool. 
 
b.  If one or more of the subpools are reactive, we recommend that you 
release from quarantine the individual donations that comprise the non-
reactive subpools provided that serologic tests on those donor samples are 
negative and the donations are otherwise suitable for release.  Consistent 
with the manufacturers instructions, you must test the individual 
donations that comprise the reactive subpool(s) using the same Single 
Virus NAT method that was used in the original NAT on the minipool  
(21 CFR 610.40(b)). 
 
15  Contains Nonbinding Recommendations 
 
(1) If all individual donor samples are non-reactive, we recommend that 
you release from quarantine all individual donations provided that 
serologic tests on those donor samples are negative and the donations 
are otherwise suitable for release.  See the NOTE in section IV.A.1.a. 
of this document on laboratory control procedures and the possible 
need to conduct additional analyses to determine the cause of the 
initial reactivity of the unresolved minipool. 
 
(2) If one or more individual donor sample(s) are reactive, perform steps 1 
through 4 in section IV.D. of this document (including product 
disposition, donor management, and lookback). 
 
We recommend that you release from quarantine all non-reactive individual donations 
provided that serologic tests on those donor samples are negative and the donations 
are otherwise suitable for release. 
 
METHOD 2:  For comparatively small minipools, for example, minipools that consist of 
up to 24 individual samples, deconstruction of the NAT-reactive minipool may be 
performed by directly testing the individual donor samples that formed the minipool (see 
Figure 2 and Table 2 below). 
 
2.  If you directly test the samples from individual donors that constituted the NAT-
reactive minipool, in accordance with the manufacturers instructions you must 
test the individual donor samples using the same Single Virus NAT method that 
was used in the original NAT on the minipool (21 CFR 610.40(b)). 
 
NOTE:  In some cases the manufacturer's instructions provide for a different sample 
preparation procedure.  However, the primers and probes would be the same as those 
used in the original NAT on the minipool. 
 
a.  If all individual donor samples are non-reactive, we recommend that you 
perform the steps in section IV.B.1.b.(1) of this document. 
 
b.  If one or more individual donor sample(s) are reactive, perform steps 1 
through 4 in section IV.D. of this document (including product 
disposition, donor management, and lookback). 
 
We recommend that you release from quarantine all non-reactive individual donations 
provided that serologic tests on those donor samples are negative and the donations 
are otherwise suitable for release. 
16  Contains Nonbinding Recommendations 
 
FIGURE 2.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Single Virus NAT (MP-NAT):  Resolution by Testing 
Subpools or by Testing Individual Donor Samples 
 
Minipool Reactive on HIV-1 NAT and/or HCV MP-NAT 
 
                                                METHOD 1                       METHOD 2 
 
    TEST SUBPOOLS1`  
    USING SAME SINGLE VIRUS  
    NAT METHOD2 
 
                                                           
                                         Non-Reactive    
                                             Subpools                                             
 
 
                                                                          
       Reactive                      RELEASE3         
     Subpool(s)                   ALL UNITS 
                               
 
                                                        TEST INDIVIDUAL DONOR SAMPLES USING                   
SAME SINGLE VIRUS NAT METHOD2                                         
                                                       
                                                                            
                                                                  
                                                                             Reactive                Non-Reactive 
                                                                     Donor Sample(s)       Donor Samples 
                                                                                                                                                
                                                         
  
                                                                                                                                R   E   LEASE3 
   ALL UNITS 
   
PERFORM THE STEPS IN FIGURE 4 FOR PRODUCT DISPOSITION, 
DONOR MANAGEMENT, AND LOOKBACK  
 
 
1 Several layers of deconstruction using original or freshly pooled subpools, may be needed. 
2 In some cases a different sample preparation procedure may be used per manufacturers instructions.  
However, primers and probes should be same as those used in the NAT on the minipool. 
3 Units may be released only if serologic tests for HIV-1 and HCV are negative and the units are otherwise 
suitable for release. 
17  Contains Nonbinding Recommendations 
 
TABLE 2.  Testing, Product Disposition, Donor Management, and Lookback for a 
Minipool that is Reactive on a Single Virus NAT (MP-NAT):  Resolution by Testing 
Subpools or by Testing Individual Donor Samples 
 
 
If:  Then:  After that if:   Then:  After that if:   Then: 
           
Minipool  METHOD 1:  Reactive  Test the   Reactive donor  Perform the 
Reactive on   Test  subpool(s)  individual   sample(s)  steps in Table 4 
HIV-1 MP- subpools1    donor    for product 
NAT   using same    samples    disposition, 
and/or  Single Virus    using same    donor 
HCV MP-NAT  NAT    Single Virus    management, 
method2    NAT    and lookback 
    method2     
         
       Non-reactive  Release3  
       donor samples  all units  
         
  Non-reactive    Release3    
 
   subpool(s)  all units  
 
   
 
   
 
Reactive donor  Perform the 
 
 sample(s)  steps in 
OR 
  Table 4 for 
 
  product 
 
  disposition, 
 
  donor 
METHOD 2: 
  management, 
Test the  
  and 
individual 
  lookback 
donor 
   
samples 
Non-reactive   
using 
 donor samples   
same Single 
Release3  
Virus NAT 
all units 
method2  
 
 
 
1 Several layers of deconstruction using original or freshly pooled subpools may be needed. 
2 In some cases a different sample preparation procedure may be used per manufacturers instructions.  
However, primers and probes should be same as those used in the NAT on the minipool. 
3 Units may be released only if serologic tests for HIV-1 and HCV are negative and the units are otherwise 
suitable for release.  
18  Contains Nonbinding Recommendations 
 
As discussed in Sections C and D below, currently approved tests on individual donor samples 
for HIV-1 RNA and HCV RNA may be either Multiplex NAT for the simultaneous detection of 
HIV-1 RNA and HCV RNA, or Single Virus NATs conducted separately for the RNA of the two 
viruses. 
 
C.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Multiplex NAT (ID-NAT) 
after Negative Antibody Screening Tests 
 
If you obtain a reactive Multiplex HIV-1 RNA/HCV RNA NAT result on an individual 
donor sample (ID-NAT), you must do the following (see Figure 3 and Table 3): 
 
1.  Follow the manufacturer's instructions, which instruct you to test the reactive 
donation using Discriminatory NATs, when necessary (21 CFR 610.40(b)). 
 
a.  If the sample is reactive for HIV-1 RNA and/or HCV RNA, you must 
quarantine the unit (21 CFR 610.40(h)).  You must not ship or use the unit 
unless one of the exceptions described in 21 CFR 610.40(h)(2) applies. 
 
If you choose not to destroy the unit, you may release it for research or further 
manufacture with written approval from FDA (21 CFR 610.40(h)(2)(ii)(A).  If 
released for one of these uses, you must appropriately label such blood or 
blood components as required under 21 CFR 606.121 and with the 
BIOHAZARD legend (21 CFR 610.40(h)(2)(ii)(B)).  Under  
21 CFR 610.40(h)(2)(ii)(C), except for autologous donations, you must label 
such human blood and blood components as reactive for the appropriate 
screening test for evidence of infection due to the identified communicable 
disease agent(s).  We recommend that you use one of the following 
statements, as applicable: 
 
  Reactive for HIV-1 RNA or 
  Reactive for HCV RNA or 
  Reactive for HIV-1 RNA and HCV RNA. 
 
Under 21 CFR 610.40(h)(2)(ii)(E), you must also include the following 
statement, as applicable: 
 
  Caution:  For Further Manufacturing Into In Vitro Diagnostic 
Reagents For Which There Are No Alternative Sources or 
  Caution:  For Laboratory Research Use Only. 
 
You must defer the donor (21 CFR 610.41).  The donor may be eligible for 
reentry (see sections V.A. and V.B.).  You must notify the donor of his/her 
deferral, providing information about the test results that were the basis for the 
deferral (21 CFR 630.40). 
 
19  Contains Nonbinding Recommendations 
 
Under 21 CFR 610.46 and 21 CFR 610.47 you must perform lookback 
(product quarantine/retrieval and notification of recipients of prior collections) 
for HIV-1 and/or HCV, respectively, as follows: 
 
  If you are an establishment that collects Whole Blood or blood 
components, including Source Plasma and Source Leukocytes, within 
3 calendar days after a donor tests reactive for evidence of HIV-1 
and/or HCV infection using the Discriminatory NATs, you must 
review records dating back 12 months prior to the donors reactive 
NAT to identify blood and blood components previously donated by 
the donor.  You must quarantine identified in-date blood and blood 
components if intended for transfusion or if intended for further 
manufacture into injectable products (except if pooled), notify 
consignees so that they may quarantine previously collected in-date 
blood and blood components, and notify transfusion recipients. 
 
  If you are a consignee of Whole Blood or blood components, including 
Source Plasma and Source Leukocytes, when notified by the collecting 
establishment you must quarantine identified previously collected in-
date blood and blood components if intended for transfusion or if 
intended for further manufacture into injectable products (except if 
pooled).  You must notify transfusion recipients who were transfused 
with blood and blood components collected during the 12 months 
before the date of the Discriminatory NAT-reactive donation, or notify 
the recipients physician of record, of the need for recipient HIV-1 or 
HCV testing and counseling.  You must make reasonable attempts to 
perform the notification within 12 weeks after receiving the donors 
Discriminatory NAT-reactive result for HIV-1 or HCV.  If both 
Discriminatory NATs were reactive, notification of transfusion 
recipients should specify that the patient should be tested for both 
HIV-1 and HCV. 
 
b.  If the Discriminatory NATs are non-reactive for both HIV-1 RNA and 
HCV RNA, the sample is Non-Discriminated Reactive (NDR)  
 
You must quarantine the unit and destroy or re-label the unit as described in 
section IV.C.1.a. 
 
You must defer the donor (21 CFR 610.41).  We recommend that you defer 
the donor for 6 months.  The donor is eligible for reentry after the 6-month 
waiting period.  If you chose to reenter the donor, you may do so at that time 
without testing a follow-up sample.  You must notify the donor of his/her 
deferral, providing information about the test results that were the basis for the 
deferral (21 CFR 630.40).  We recommend that you counsel the donor that the  
   
20  Contains Nonbinding Recommendations 
 
initial test result was very likely a false positive result and that the donor is not 
infected, but that because of the initial reactive test result he or she will be 
deferred for 6 months. 
 
You must perform lookback for HIV-1 and HCV under 21 CFR 610.46 and 
610.47, respectively, as described in section IV.C.1.a. above. 
 
 
FIGURE 3.  Testing, Product Disposition, Donor Management, and Lookback for 
an Individual Donor Sample that is Reactive on a Multiplex NAT (ID-NAT) after 
Negative Antibody Screening Tests 
 
Individual Donor Sample Reactive on a Multiplex HIV-1/HCV ID-NAT 
 
 
                                                         
TEST TO DISCRIMINATE HIV-1 AND HCV, AS NECESSARY  
  
 
         _________________________________________________________________________________     
Reactive for HIV-1 and/or HCV         Non-Reactive for both HIV-1 and HCV 
                                                                                                        (Non-Discriminated Reactive) 
      
                                                                                                                           
                                                                                        
                                                                                                                                     
        QUARANTINE AND DESTROY                   QUARANTINE AND DESTROY 
                OR RE-LABEL UNIT.                                      OR RE-LABEL UNIT. 
         DEFER1 AND NOTIFY DONOR.         DEFER3 AND NOTIFY DONOR.4 
         PERFORM LOOKBACK2  FOR                      PERFORM LOOKBACK2        
                  HIV-1 AND/OR HCV,                                  FOR HIV-1 AND HCV.     
                AS APPROPRIATE. 
             
 
                            
                                                         
                                                                     
                                                  
1The donor may be eligible for reentry (see Figures 5 and 6). 
2 If both Discriminatory NATs were reactive or if both Discriminatory NATs were non-reactive, notification 
of transfusion recipients should specify that the patient should be tested for both HIV-1 and HCV.  
 3 We recommend that you defer the donor for 6 months and, if you choose to reenter the donor, you may do 
so at that time without testing a follow-up sample. 
4 We recommend that you counsel the donor that the test result was very likely a false positive result and that 
the donor is not infected, but that because of the initial reactive test result he or she will be deferred for 6 
months.   
   
21  Contains Nonbinding Recommendations 
 
TABLE 3.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Multiplex NAT (ID-NAT) after Negative 
Antibody Screening Tests 
 
If:  Then:  After that if:  Then: 
       
Individual  Test to  Reactive for  Quarantine and 
Donor  discriminate  HIV-1 and/or  destroy or re-label 
Sample  HIV-1 and  HCV  unit;  
Reactive on  HCV, as    Defer1 and notify 
a Multiplex  necessary     donor; perform 
HIV-1 /HCV      lookback2 for HIV-1 
ID-NAT      and/or HCV, as 
    appropriate 
   
 
 
 
 
   
  Quarantine and 
  destroy or re-label 
  unit;  
Non-Reactive  Defer3 and notify 
for both HIV-1   donor4; perform 
and HCV  lookback2 for HIV-1 
and HCV 
1The donor may be eligible for reentry (see Tables 5 and 6). 
2 If both Discriminatory NATs were reactive or if both Discriminatory NATs were non-reactive, notification 
of transfusion recipients should specify that the patient should be tested for both HIV-1 and HCV.  
3 We recommend that you defer the donor for 6 months and, if you choose to reenter the donor, you may do 
so at that time without testing a follow-up sample.  
4 We recommend that you counsel the donor that the test result was very likely a false positive result and that 
the donor is not infected, but that because of the initial reactive test result he or she will be deferred for 6 
months. 
 
   
22  Contains Nonbinding Recommendations 
 
D.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Single Virus NAT (ID-NAT) 
after Negative Antibody Screening Tests 
   
If you obtain a reactive HIV-1 RNA NAT and/or reactive HCV RNA NAT result for an 
individual donor sample from a test other than a Multiplex NAT, you must do the 
following (see Figure 4 and Table 4): 
 
1.  Quarantine the unit (21 CFR 610.40(h)).  You must not ship or use the unit unless 
one of the exceptions described in 21 CFR 610.40(h)(2) applies.  If you choose 
not to destroy the unit, you may release it for research or further manufacture with 
written approval from FDA.  If released for one of these uses, you must 
appropriately label the unit as described in section IV.C.1.a. (21 CFR 606.121). 
 
2.  Defer the donor (21 CFR 610.41).  The donor may be eligible for reentry (see 
sections V.A. and V.B.). 
 
3.  Notify the donor of his/her deferral, providing information about the test results 
that were the basis for the deferral (21 CFR 630.40). 
 
4.  Perform lookback (product quarantine/retrieval and notification of recipients of 
prior collections) for HIV-1 and/or HCV under 21 CFR 610.46 and  
21 CFR 610.47 respectively, as appropriate. 
 
  If you are an establishment that collects Whole Blood or blood 
components, including Source Plasma and Source Leukocytes, within 
3 calendar days after a donor tests reactive for evidence of HIV-1 
and/or HCV infection you must review records dating back 12 months 
prior to the donors reactive NAT to identify blood and blood 
components previously donated by the donor.  You must quarantine 
identified in-date blood and blood components if intended for 
transfusion or if intended for further manufacture into injectable 
products (except if pooled), notify consignees so that they may 
quarantine previously collected in-date blood and blood components, 
and notify transfusion recipients. 
  
   If you are a consignee of Whole Blood or blood components, 
including Source Plasma and Source Leukocytes, when notified by the 
collecting establishment you must quarantine identified previously 
collected in-date blood and blood components if intended for 
transfusion or if intended for further manufacture into injectable 
products (except if pooled).  You must notify transfusion recipients 
who were transfused with blood and blood components collected 
during the 12 months before the date of the NAT-reactive donation, or 
notify the recipients physician of record, of the need for recipient 
HIV-1 or HCV testing and counseling.  You must make reasonable 
23  Contains Nonbinding Recommendations 
 
attempts to perform the notification within 12 weeks after receiving 
the donors reactive NAT screening test result for HIV-1 or HCV.  If 
both Single Virus NATs were reactive, notification of transfusion 
recipients should specify that the patient should be tested for both 
HIV-1 and HCV. 
 
   
24  Contains Nonbinding Recommendations 
 
FIGURE 4.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Single Virus NAT (ID-NAT) after Negative 
Antibody Screening Tests 
 
 
Individual Donor Sample Reactive on HIV-1 ID-NAT and/or HCV ID-NAT 
 
 
 
 
QUARANTINE AND DESTROY OR RE-LABEL UNIT. 
DEFER DONOR.1 
NOTIFY DONOR. 
 
PERFORM LOOKBACK FOR HIV-1 AND/OR HCV, AS APPROPRIATE.  
 
 
1The donor may be eligible for reentry (see Figures 5 and 6). 
 
 
 
 
TABLE 4.  Testing, Product Disposition, Donor Management, and Lookback for an 
Individual Donor Sample that is Reactive on a Single Virus NAT (ID-NAT) after Negative 
Antibody Screening Tests 
 
 
If:  Then: 
   
Individual Donor Sample  Quarantine the unit 
Reactive on HIV-1 ID-NAT   
and/or HCV ID-NAT   
Destroy or re-label the unit 
 
Defer the donor1 
 
 
Notify the donor 
 
 
Perform lookback for HIV-1 and/or HCV, as appropriate 
 
1 The donor may be eligible for reentry (see Tables 5 and 6). 
   
25  Contains Nonbinding Recommendations 
 
V.  RECOMMENDATIONS FOR DONOR REENTRY 
 
Note that the reentry of a donor permits prospective donations from a reentered donor who meets 
donor eligibility criteria.  It does not affect the status of previous collections from that donor, 
including donations subject to lookback. 
 
A.  Reentry for Donors Deferred Because of Reactive HIV-1/2 Test Results 
 
Currently, FDA has not found acceptable a process for reentry of deferred donors with 
the following HIV-1 test results: 
 
  NAT-reactive for HIV-1 (e.g., a Discriminatory NAT after a reactive 
Multiplex NAT or by a Single Virus NAT for HIV-1 RNA) and anti-HIV-1 or 
-2 or anti-HIV-1/2 test RR (regardless of HIV-1 WB or IFA or HIV-1 p24 
EIA test result); 
 
OR 
 
  NAT-reactive for HIV-1 (e.g., a Discriminatory NAT after a reactive 
Multiplex NAT or by a Single Virus NAT for HIV-1 RNA) and HIV-1 p24 
EIA RR (regardless of anti-HIV-1 or -2 or anti-HIV-1/2 test result); 
 
OR 
 
  NAT-non-reactive for HIV-1 (or HIV-1 NAT not performed) and anti-HIV-1 
or -2 or anti-HIV-1/2 test RR, HIV-1 WB positive (regardless of HIV-1 p24 
EIA test result). 
 
OR 
 
  NAT-non-reactive for HIV-1 (or HIV-1 NAT not performed) and anti-HIV-1 
or -2 or anti-HIV-1/2 test RR (regardless of WB or IFA result) and HIV-1 p24 
EIA RR (regardless of Neutralization test result). 
 
1.  FDA has accepted a method or process for reentry of deferred donors in the 
following three groups (see Figure 5 and Table 5): 
 
  Group I:  Donors who were HIV-1 NAT-reactive (i.e., reactive on a 
Discriminatory NAT for HIV-1 or on a Single Virus NAT for HIV-1 or a 
Multiplex NAT that detects and discriminates HIV) and seronegative.  
This includes donors previously deferred because of reactive test results 
on an investigational HIV-1 NAT.  The HIV-1 p24 antigen EIA may not 
have been performed if it was replaced by an approved NAT that was 
validated to replace the HIV-1 p24 antigen test. 
 
26  Contains Nonbinding Recommendations 
 
NOTE:  If the original donor sample that was NAT-reactive was negative on 
the Discriminatory NAT for HIV-1 or on the Single Virus NAT for HIV-1 but 
was reactive on the Discriminatory NAT for HCV or on the Single Virus NAT 
for HCV, you may attempt to reenter the donor according to the 
recommendations in section V.B. (see Figure 6 and Table 6).  If the original 
donor sample that was NAT-reactive was reactive on both of the 
Discriminatory NATs for HIV-1 and HCV or on both of the Single Virus 
NATs for HIV-1 and HCV, or reactive for both HIV-1 and HCV on the 
Multiplex test that detects and discriminates HIV and HCV, you may attempt 
to reenter the donor according to the recommendations in both sections V.A 
and V.B (see Figures 5 and 6, and Tables 5 and 6). 
 
  Group II:  Donors who were NAT-non-reactive (or NAT was not performed) 
and who were RR on a screening test for HIV-1 or -2 or HIV-1 and -2 or HIV-
1/2 antibody, with an HIV-1 WB or IFA that was indeterminate (viral bands 
may be present), unreadable, negative, or was not performed.  If an HIV-1 
IFA was performed to resolve an indeterminate or unreadable HIV-1 WB, the 
IFA result must not have been positive.  This group includes donors 
previously deferred because of RR HIV-1 or HIV-2 (or combination HIV-1/2) 
serologic test results prior to the initiation of testing by NAT. 
 
These donors may be eligible for reentry only if:  
  the HIV-1 p24 antigen EIA (if performed) was negative, and  
o
  if a second, different, licensed HIV-2 test performed on the index 
o
donation was negative, or, if the second HIV-2 test was RR, an 
investigational HIV-2 supplemental test (if performed) was not 
positive.  Performance of an investigational HIV-2 supplemental test 
(if available) is optional at the present time.  Currently, we have not 
approved a supplemental test for HIV-2.  If a supplemental test for 
HIV-2 is licensed in the future, that test must be performed in 
accordance with 21 CFR 610.40(e), and the result of the supplemental 
test for HIV-2 must not be positive for the donor to be eligible for 
reentry. 
 
  Group III:  Donors who were NAT-non-reactive (or NAT was not 
performed) and who were negative on a screening test for HIV-1 and -2 or 
HIV-1/2 antibody, but who were RR on an HIV-1 p24 antigen EIA with an 
indeterminate (that is, a non-neutralized or an invalid) or a positive result on 
the Neutralization test, even on more than one occasion. 
 
   
27  Contains Nonbinding Recommendations 
 
2.  To reenter a donor who meets FDA eligibility criteria (i.e., the donor is otherwise 
eligible to donate again), we recommend that you do the following (see Figure 5 
and Table 5): 
 
a.  At least 8 weeks after the original donation obtain a new sample from 
the donor (no donation is made at this time) and perform follow-up testing 
using: 
 
(1) A licensed ID-NAT for HIV-1 (e.g., a Discriminatory NAT for 
HIV-1 or a Single Virus NAT for HIV-1).   
 
If the original donor sample was reactive on the NAT for HIV-1 
(Group I donors), we recommend that you use the same ID-NAT 
(i.e., the Discriminatory NAT for HIV-1 or the Single Virus NAT 
for HIV-1 or Multiplex NAT that detects and discriminates HIV) 
that was run on the original donor sample.  If the original NAT is 
no longer available (e.g., an investigational NAT), we recommend 
that you use a NAT that has the same sensitivity claims as the 
original NAT, or greater sensitivity claims (e.g., a NAT labeled in 
the Intended Use as sensitive for HIV-1 including Group O, if 
available).  
 
AND 
 
(2) A licensed anti-HIV-1/2 test.  
 
If the original donor sample was RR on the anti-HIV-1 or anti-
HIV-1/2 test (Group II donors), we recommend that you use that 
same test to test this follow-up sample.  If the original donor 
sample was negative on the anti-HIV-1 or anti-HIV-1/2 test 
(Group I donors or Group III donors), or if the original test is no 
longer available, we recommend that you use an anti-HIV-1/2 test 
that is labeled in the Intended Use as sensitive for HIV-1 Group O.  
 
NOTE:  For purposes of donor counseling, you may choose to test 
the deferred donor with an HIV-1 ID-NAT and an anti-HIV-1/2 
test at any time prior to the end of this 8-week waiting period after 
the original donation.  However, if an HIV-1 ID-NAT is reactive 
prior to the end of this 8-week waiting period, the donor would not 
be eligible for reentry and we recommend that you defer the donor 
permanently.  If an anti-HIV-1/2 test is RR prior to the end of this 
8-week waiting period, and a licensed supplemental test for 
antibodies to HIV-1 (e.g., WB or IFA), if performed, is not 
positive, you may take another follow-up sample from the donor 
for testing by both HIV-1 ID-NAT and an anti-HIV-1/2 test after 
another 8-week waiting period has passed.   
28  Contains Nonbinding Recommendations 
 
 
b.  Evaluate the results of the follow-up testing on the donors new 
sample as follows: 
 
(1) If the ID-NAT is reactive and the anti-HIV-1/2 test is RR, we 
recommend that you defer the donor permanently.   
 
(2) If the ID-NAT is reactive and the anti-HIV-1/2 test is negative, 
we recommend that you defer the donor permanently.   
 
(3) If the ID-NAT is non-reactive and the anti-HIV-1/2 test is RR, 
you may reconsider the donor for reentry by conducting additional 
follow-up testing after a second waiting period of 8 weeks. 
 
(4) When there is a persistent anti-HIV-1/2 RR result, you may 
wish to further test the donors new sample using a licensed 
supplemental test for antibodies to HIV-1 such as a WB or IFA.  If 
the WB or IFA test result is indeterminate, unreadable, or negative, 
you may reconsider the donor for reentry by conducting follow-up 
testing after one or more additional waiting period of 8 weeks.  If 
the WB or IFA test result is positive, we recommend that you defer 
the donor permanently. 
 
(5) If the ID-NAT is non-reactive and the anti-HIV-1/2 test is 
negative, you may reenter the donor (i.e., the donor is eligible to 
donate in the future, provided the donor meets all donor eligibility 
criteria). 
29  Contains Nonbinding Recommendations 
 
FIGURE 5.  Reentry for Donors Deferred Because of Reactive HIV-1/2 Test Results 
 
           Group I                                  Group II                                     Group III 
 
NAT Reactive1                        NAT Non-Reactive or Not Done        NAT Non-Reactive or Not Done  
Anti-HIV-1/2 Test Negative            Anti-HIV-1/2 Test RR                     Anti-HIV-1/2 Test Negative 
HIV-1 p24 EIA2 Negative                   HIV-1 WB or IFA                        HIV-1 p24 EIA RR, 
       Indeterminate, Unreadable,               Neutralization Test(s)  
                             Negative, or Not Done                         Positive or Indeterminate 
                                                              HIV-1 p24 EIA2 Negative                     (Non-Neutralized or Invalid)                       
                                                              Second, different HIV-2 Test                      
                                                     Negative or, if RR,     
                                                     Investigational3 HIV-2   
                                                                Supplemental test (if   
                                                                performed) was not Positive                                      
 
 
 
 
 
       AFTER 8 WEEKS4, 
   TEST FOLLOW-UP SAMPLE USING 
 HIV-1 ID-NAT5,6 AND ANTI-HIV-1/2 TEST7 
 
                                                                    
 
                                            
________________________________________________________________________ 
ID-NAT Reactive /     ID-NAT Reactive /   ID-NAT Non-Reactive /   ID-NAT Non-Reactive / 
      Anti-HIV-1/2      Anti-HIV-1/2      Anti-HIV-1/2                   Anti-HIV-1/2 
         Test RR                    Test Negative                   Test RR                       Test Negative         
 
 
 
 
                                                                                                
DEFER DONOR        DEFER DONOR       DEFER DONOR     REENTER DONOR 
PERMANENTLY      PERMANENTLY     AND CONTINUE      (Donor Eligible for 
                                                                           FOLLOW-UP8            Future Donation, 
                                                                                                             Provided Donor Meets 
                                                                                                                 Eligibility Criteria) 
 
______________________________________________________________________________ 
   
30  Contains Nonbinding Recommendations 
 
Footnotes for FIGURE 5. 
 
1 Reactive for HIV-1 (i.e., a Discriminatory NAT for HIV-1 or on a Single Virus NAT for HIV-1 or a 
Multiplex NAT that detects and discriminates HIV)   
2 May not have been performed, depending upon the conditions of the specific NAT approval. 
3 Performance of an investigational HIV-2 supplemental test (if available) is optional.  If a supplemental test 
is licensed in the future it must be performed in accordance with 21 CFR 610.40(e) and it must not have been 
positive for the donor to be eligible for reentry.  
4 HIV-1 ID-NAT and/or an anti-HIV-1/2 test, if performed during the 8 week waiting period, must be 
negative for the donor to be eligible for reentry.  
5 If the original donor sample was reactive on both of the Discriminatory NAT tests for HIV-1 and HCV, we 
recommend that you test a follow-up sample using HCV ID-NAT and an anti-HCV test also, as in the HCV 
Reentry Algorithm (see Figure 6). 
6 If the original donor sample was reactive on the NAT for HIV-1 (Group I donors), we recommend that you 
use the same ID-NAT (i.e., the Discriminatory NAT for HIV-1 or the Single Virus NAT for HIV-1 or the 
Multiplex NAT that detects and discriminates HIV) that was run on the original donor sample.  If the 
original NAT is no longer available (e.g., an investigational NAT), we recommend that you use a NAT that 
has the same sensitivity claims as the original NAT or greater sensitivity claims (e.g., a NAT labeled in the 
Intended Use as sensitive for HIV-1 including Group O, if available).  
7 If the original donor sample was RR on the anti-HIV-1/2 test (Group II donors) we recommend that you use 
that same test to test this follow-up sample.  If the original donor sample was negative on the anti-HIV-1/2 
test (Group I donors or Group III donors) or if the original test is no longer available, we recommend that 
you use an anti-HIV-1/2 test that is labeled in the Intended Use as sensitive for HIV-1 including Group O. 
8 At your option you may further test the donors sample using HIV-1 WB or IFA.  If WB or IFA is negative, 
unreadable, or indeterminate, you may reconsider the donor for reentry by conducting follow-up testing after 
one or more additional waiting period of 8 weeks.  If WB or IFA is positive, we recommend that you defer the 
donor permanently. 
 
31  Contains Nonbinding Recommendations 
 
TABLE 5.  Reentry for Donors Deferred Because of Reactive HIV-1/2 Test Results 
 
If:  Then:  After that if:  Then: 
       
Group I:       ID-NAT Reactive/  Defer donor 
       Anti-HIV-1/2 Test RR  permanently 
NAT Reactive1         
Anti-HIV-1/2 Test Negative       
HIV-1 p24 EIA2 Negative       
       ID-NAT  Reactive/  Defer donor 
OR  After 8 weeks4,     Anti-HIV-1/2 Test Negative  permanently 
  test follow-up     
Group II:  sample using     
   
  HIV-1 ID-
NAT Non-Reactive or Not  NAT5,6 and     ID-NAT Non-Reactive/  Defer donor and 
   Anti-HIV-1/2 Test RR  continue follow-
    Done  Anti-HIV-1/2 
Anti-HIV-1/2 Test RR   Test7    up8 
HIV-1 WB or IFA     
 
    Indeterminate, Unreadable,   
 
    Negative, or Not Done     ID-NAT Non-Reactive/ 
REENTER 
HIV-1 p24 EIA2 Negative     Anti-HIV-1/2 Test Negative 
DONOR 
Second, different HIV-2 Test 
(Donor eligible 
     Negative, or if RR, 
for future 
     Investigational3 HIV-2   
donation, 
     Supplemental test (if   
provided donor 
     performed) was not 
meets eligibility 
     Positive 
criteria) 
 
 
OR 
 
Group III: 
 
NAT Non-Reactive or  
     Not Done 
Anti-HIV-1/2 Test Negative 
HIV-1 p24 EIA RR,  
     Neut. Test(s) Positive or  
     Indeterminate (Non- 
     Neutralized or Invalid) 
 
   
32  Contains Nonbinding Recommendations 
 
Footnotes for TABLE 5. 
 
1 Reactive for HIV-1 (i.e., on a Discriminatory NAT for HIV-1 or on a Single Virus NAT for HIV-1 or the 
Multiplex NAT that detects and discriminates HIV).  
2 May not have been performed, depending upon the conditions of the specific NAT approval. 
3 Performance of an investigational HIV-2 supplemental test (if available) is optional.  If a supplemental test 
is licensed in the future it must be performed in accordance with 21 CFR 610.40(e) and it must not have been 
positive for the donor to be eligible for reentry.  
4 HIV-1 ID-NAT and/or an anti-HIV-1/2 test, if performed during the 8 week waiting period, must be 
negative for the donor to be eligible for reentry. 
5 If the original donor sample was reactive on both of the Discriminatory NAT tests for HIV-1 and HCV, we 
recommend that you test a follow-up sample using HCV ID-NAT and an anti-HCV test also, as in the HCV 
Reentry Algorithm (see Figure 6). 
6 If the original donor sample was reactive on the NAT for HIV-1 (Group I donors), we recommend that you 
use the same ID-NAT (i.e., the Discriminatory NAT for HIV-1 or the Single Virus NAT for HIV-1 or the 
Multiplex NAT that detects and discriminates HIV) that was run on the original donor sample.  If the 
original NAT is no longer available (e.g., an investigational NAT), we recommend that you use a NAT that 
has the same sensitivity claims as the original NAT or greater sensitivity claims (e.g., a NAT labeled in the 
Intended Use as sensitive for HIV-1 including Group O, if available).  
7 If the original donor sample was RR on the anti-HIV-1/2 test (Group II donors) we recommend that you use 
that same test to test this follow-up sample.  If the original donor sample was negative on the anti-HIV-1/2 
test (Group I donors or Group III donors) or if the original test is no longer available, we recommend that 
you use an anti-HIV-1/2 test that is labeled in the Intended Use as sensitive for HIV-1 including Group O. 
8 At your option you may further test the donors sample using HIV-1 WB or IFA.  If WB or IFA is negative, 
unreadable, or indeterminate, you may reconsider the donor for reentry by conducting follow-up testing after 
one or more additional waiting period of 8 weeks.  If WB or IFA is positive, we recommend that you defer the 
donor permanently. 
 
B.  Reentry for Donors Deferred Because of Reactive HCV Test Results 
 
Currently, FDA has not found acceptable a process for reentry of deferred donors with 
the following HCV test results:   
 
  NAT-reactive for HCV (e.g., a Discriminatory NAT after a reactive Multiplex 
NAT or by a separate NAT for HCV RNA) and anti-HCV test RR (regardless 
of historical HCV RIBA result)   
 
OR 
 
  NAT-non-reactive for HCV (or HCV NAT not performed) and anti-HCV test 
RR and historical HCV RIBA positive  
 
1.  FDA has accepted a method or process for reentry of deferred donors in the 
following two groups (see Figure 6 and Table 6):   
 
  Group A:  Donors who were HCV NAT-reactive (e.g., reactive on a 
Discriminatory NAT for HCV or on a Single Virus NAT for HCV) and 
seronegative.  This includes donors previously deferred because of 
reactive test results on an investigational HCV NAT.   
 
33  Contains Nonbinding Recommendations 
 
NOTE:  If the original donor sample that was NAT-reactive was negative 
on the Discriminatory NAT for HCV or on the Single Virus NAT for 
HCV but was reactive on the Discriminatory NAT for HIV-1 or on the 
Single Virus NAT for HIV-1, you may attempt to reenter the donor 
according to the recommendations in section V.A. (see Figure 5 and Table 
5).  If the original donor sample that was NAT-reactive was reactive on 
both of the Discriminatory NATs for HIV-1 and HCV or on both of the 
Single Virus NATs for HIV-1 and HCV or for both HIV-1 and HCV on 
the Multiplex test that detects and discriminates HIV and HCV, you may 
attempt to reenter the donor according to the recommendations in both 
sections V.A and V.B (see Figures 5 and 6 and Tables 5 and 6). 
 
  Group B:  Donors who were NAT-non-reactive (or NAT was not 
performed) and who were RR on a screening test for HCV antibody.5 This 
group includes donors who were RR on a second, different licensed 
screening test for HCV antibody if it was used in further testing of the 
index donation in accordance with 21 CFR 610.40(e).  
 
2.  To reenter a donor who meets FDA eligibility criteria (i.e., the donor is otherwise 
eligible to donate again), we recommend that you do the following (see Figure 6 
and Table 6): 
 
a.  At least 6 months after the original donation obtain a new sample from the 
donor (no donation is made at this time) and perform follow-up testing using: 
 
(1) A licensed ID-NAT for HCV (e.g., a Discriminatory NAT for 
HCV or a Single Virus NAT for HCV) 
 
If the original donor sample was reactive on the NAT for HCV 
(Group A donors), we recommend that you use the same ID-NAT 
(i.e., the Discriminatory NAT for HCV or the Single Virus NAT 
for HCV or the Multiplex NAT that detects and discriminates 
HCV) that was run on the original donor sample.  If the original 
NAT is no longer available (e.g., an investigational NAT) we 
recommend you use a NAT that has the same sensitivity claims as 
the original NAT or greater sensitivity claims. 
 
AND 
 
(2) Two different, licensed anti-HCV screening tests.   
 
If the original donor sample was RR on the anti-HCV test (Group B 
donors), we recommend that you use the same anti-HCV test that was 
performed on the original donor sample or a more sensitive version (i.e., 
                                                 
5 This group includes deferred donors with an historical HCV RIBA that was indeterminate, negative or was not 
performed. 
34  Contains Nonbinding Recommendations 
 
HCV EIA version 3.0 or later) as one of the two licensed-anti HCV 
screening tests to test this follow-up sample.  
 
NOTE:  For purposes of donor counseling and to detect possible HCV 
viremia, you may also choose to test the deferred donor with an HCV ID-
NAT and two different, licensed anti-HCV screening tests at any time 
prior to the completion of the 6-month period after the original donation.  
However, if an HCV ID-NAT is reactive prior to the end of this 6-month 
period, the donor would not be eligible for reentry and we recommend that 
you defer the donor permanently.  If an anti-HCV test is RR prior to the 
end of this 6-month waiting period,  you may take one more follow-up 
sample from the donor after a waiting period of at least 6 months for 
testing by HCV ID-NAT and two different, licensed anti-HCV screening 
tests.  If an anti-HCV test is still RR on a second follow-up sample at any 
time after the original donation, we recommend that you defer the donor 
permanently. 
 
b.  Evaluate the results of the follow-up testing on the donors new sample as 
follows: 
 
(1) If the ID-NAT is reactive regardless of anti-HCV test results, we 
recommend that you defer the donor permanently. 
 
(2) If the ID-NAT is non-reactive and both of the anti-HCV tests 
are RR, we recommend that you defer the donor permanently. 
 
(3) If the ID-NAT is non-reactive and only one anti-HCV test is RR, 
you may reconsider the donor for reentry by testing a follow-up 
sample after one more waiting period of at least 6 months.  If an 
anti-HCV test is still RR on a second follow-up sample at any time 
after the original donation, we recommend that you defer the donor 
permanently. 
 
(4) If the ID-NAT is non-reactive and both anti-HCV tests are 
negative, you may reenter the donor (i.e., the donor is eligible to 
donate in the future, provided the donor meets all donor eligibility 
criteria). 
35  Contains Nonbinding Recommendations 
 
FIGURE 6.  Reentry for Donors Deferred Because of Reactive HCV Test Results 
 
                           Group A                                                       Group B 
 
                    NAT Reactive1                                      NAT Non-Reactive or Not Done 
                    Anti-HCV Test Negative                      Anti-HCV Test(s) RR2 
                                                                                    
                                                                                        
                                                                                                                                      
                            
                                                         
AFTER 6 MONTHS3, 
TEST FOLLOW-UP SAMPLE USING 
HCV ID-NAT4,5  AND TWO DIFFERENT, LICENSED ANTI-HCV SCREENING TESTS6 
 
                                                                 
________________________________________________________________________ 
 
ID-NAT Reactive/    ID-NAT Non-Reactive/   ID-NAT Non-Reactive/  ID-NAT Non-Reactive/  
  Regardless of          Both Anti-HCV             One Anti-HCV             Both Anti-HCV   
  Anti-HCV Test     Tests RR                   Test RR and            Tests Negative 
  Results                                  One Anti-HCV                                     
             Test Negative  
 
 
 
 
 DEFER DONOR         DEFER DONOR     DEFER DONOR      REENTER DONOR 
PERMANENTLY       PERMANENTLY    AND CONTINUE        (Donor Eligible for 
                                                                           FOLLOW-UP7             Future Donation, 
                                                                                                               Provided Donor Meets 
                                                                                                                  Eligibility Criteria) 
________________________________________________________________________ 
   
36  Contains Nonbinding Recommendations 
 
Footnotes for FIGURE 6. 
 
1 Reactive on a Discriminatory NAT for HCV or on a Single Virus NAT for HCV or on a Multiplex NAT that 
detects and discriminates HCV. 
2 Group B includes deferred donors with an historical HCV RIBA that was indeterminate, negative or was 
not performed.  Donors can be RR in a second, different licensed screening test for HCV antibody if it was 
used for further testing of the index donation.  
3 HCV ID-NAT, if performed prior to 6 months, must be negative for the donor to be eligible for reentry.  
4 If the original donor sample was reactive on both of the Discriminatory NAT tests for HIV-1 and HCV, test 
a follow-up sample using HIV-1 ID-NAT and an anti-HIV-1/2 test also, as in the HIV-1 Reentry Algorithm 
(see Figure 5). 
5 If the original donor sample was reactive on the NAT for HCV (Group A donors), we recommend that you 
use the same ID-NAT (i.e., the Discriminatory NAT for HCV or the Single Virus NAT for HCV or the 
Multiplex NAT that detects and discriminates HCV) that was run on the original donor sample.  If the 
original NAT is no longer available (e.g., an investigational NAT) we recommend you use a NAT that has the 
same sensitivity claims as the original NAT or greater sensitivity claims.  
6 If the original donor sample was RR on the anti-HCV test (Group B donors) we recommend that you use the same anti-
HCV test that was run on the original donor sample or a more sensitive version (i.e., HCV EIA version 3.0 or later) as one 
of the two licensed-anti HCV screening tests to test this follow-up sample.  
7 You may reconsider the donor for reentry by testing a follow-up sample after one more waiting period of at least 6 
months using an HCV ID NAT and two different, licensed anti-HCV screening tests.  If an anti-HCV test is still RR on a 
second follow-up sample at any time after the original donation, we recommend that you defer the donor permanently. 
37  Contains Nonbinding Recommendations 
 
TABLE 6.  Reentry for Donors Deferred Because of Reactive HCV Test Results 
 
 
If:  Then:  After that if:  Then: 
 
       
Group A:    ID-NAT Reactive/   Defer donor   
    Regardless of Anti-HCV  permanently   
NAT Reactive1    Test Results      
Anti-HCV Test Negative  After 6 months3,       
  test follow-up     
 
OR  sample using HCV      
  ID-NAT4,5 and two  ID NAT Non-Reactive/  Defer donor   
Group B:  different licensed  Both Anti-HCV Tests  permanently   
  Anti-HCV  RR     
Screening Tests6     
NAT Non-Reactive    
     or Not Done       
Anti-HCV Test(s) RR2   ID-NAT Non-Reactive/  Defer donor 
  One Anti-HCV Test RR  and   
and One Anti-HCV Test  continue   
Negative  follow-up7   
     
 
   
REENTER 
ID-NAT Non-Reactive/  
DONOR   
Both Anti-HCV Test 
(Donor   
Negative   
  eligible for   
future 
   
donation, 
 
provided 
donor meets   
eligibility   
criteria)   
1 Reactive on a Discriminatory NAT for HCV or on a Single Virus NAT for HCV or on a Multiplex NAT that 
detects and discriminates HCV. 
2 Group B includes deferred donors with an historical HCV RIBA that was indeterminate, negative or was 
not performed.  Donors can be RR in a second, different licensed screening test for HCV antibody if it was 
used for further testing of the index donation.  
3.HCV ID-NAT, if performed prior to 6 months, must be negative for the donor to be eligible for reentry. 
4 If the original donor sample was reactive on both of the Discriminatory NAT tests for HIV-1 and HCV, test 
a follow-up sample using HIV-1 ID-NAT and an anti-HIV-1/2 test also, as in the HIV-1 Reentry Algorithm 
(see Figure 5). 
5. If the original donor sample was reactive on the NAT for HCV (Group A donors), we recommend that you 
use the same ID-NAT (i.e., the Discriminatory NAT for HCV or the Single Virus NAT for HCV or the 
Multiplex NAT that detects and discriminates HCV) that was run on the original donor sample.  If the 
original NAT is no longer available (e.g., an investigational NAT) we recommend you use a NAT that has the 
same sensitivity claims as the original NAT or greater sensitivity claims.  
6 If the original donor sample was RR on the anti-HCV test (Group B donors), we recommend that you use 
the same anti-HCV test that was run on the original donor sample or a more sensitive version (i.e., HCV EIA 
version 3.0 or later) as one of the two licensed-anti HCV screening tests to test this follow-up sample. 
7 You may reconsider the donor for reentry by testing a follow-up sample after one more waiting period of at least 6 
months using an HCV ID NAT and two different, licensed anti-HCV screening tests.  If an anti-HCV test is still RR on a 
second follow-up sample at any time after the original donation, we recommend that you defer the donor permanently. 
   
38  Contains Nonbinding Recommendations 
 
VI.  REFERENCES 
 
1.  FDA Memorandum to All Registered Blood Establishments:  Revised Recommendations 
for the Prevention of Human Immunodeficiency Virus (HIV-1) Transmission by Blood and 
Blood Products, April 23, 1992. 
2.  FDA Memorandum to All Registered Blood and Plasma Establishments:  Recommendations 
for Donor Screening with a Licensed Test for HIV-1 Antigen, August 8, 1995. 
3.  FDA Memorandum to All Registered Blood Establishments:  Revised Recommendations 
for Testing Whole Blood, Blood Components, Source Plasma and Source Leukocytes for 
Antibody to Hepatitis C Virus Encoded Antigen (Anti-HCV), August 5, 1993. 
4.  Busch MP.  Closing the windows on viral transmission by blood transfusion. In Stramer SL 
ed. Blood Safety in the New Millenium. Bethesda, MD:  American Association of Blood 
Banks, 2001:  Chapter 2, p.36. 
5.  Glynn SA, Kleinman SH, Wright DJ, Busch MP.  International application of the incidence 
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