# Presentation: 029513

## Update on Rapid HIV Testing

- Bernard M. Branson, M.D.
*Chief, Lab Determinants and Diagnostics Section*
*Centers for Disease Control and Prevention*

## Outline

- New FDA-approved rapid HIV tests
- Characteristics
- Requirements for use
- Point-of-care vs laboratory testing
- Challenges for interpreting HIV antibody test results

## OraQuick HIV-1 Rapid Antibody Test: designed for oral fluid, serum, whole blood

**OraQuick HIV-1 Rapid Antibody Test: designed for oral fluid, serum, whole blood**

## FDA-approved November 7, 2002 for use with finger stick whole blood specimens;  granted CLIA waiver January 31, 2003

**FDA-approved November 7, 2002 for use with finger stick whole blood specimens;  granted CLIA waiver January 31, 2003**

## Obtain finger stick blood specimen

**Obtain finger stick blood specimen**

## Loop collects 5 microliters of whole blood

**Loop collects 5 microliters of whole blood**

## Insert loop into vial and stir

**Insert loop into vial and stir**

## Insert device; test develops in 20 minutes

**Insert device; test develops in 20 minutes**

## Positive

**Positive**

**Negative**

**Reactive Control**

**Positive**

**Read results**

## OraQuick Characteristics

- Sensitivity 98.6%        Specificity 100%
- CLIA waived
- Internal control
- Run external controls periodically
- Room temperature storage
- Suitable for point-of-care

## Bethany Hospital

- Rapid test performed on Labor and Delivery unit.
- Eligible patients are determined here in the Labor and Delivery Triage area.

## The rapid test is done on this counter, extra supplies are stored below. 

OB physicians and Midwives share MIRIAD testing at Provident.

- OB physicians and Midwives share MIRIAD testing at Provident.

**Provident Hospital**

## Cook County Hospital

- Clerks on each shift access HIV results from the computer system.
- Eligible patients are offered rapid testing and consented in the Triage area.

## Slide 14

## Reveal HIV-1 Rapid Antibody Test for serum, plasma

**FDA approved April 16, 2003- Moderate Complexity**

## Centrifuge to obtain serum or plasma

**Centrifuge to obtain serum or plasma**

## Add buffer to reconstitute conjugate and controls. (Store refrigerated up to 7 days)

**Add buffer to reconstitute conjugate and controls. (Store refrigerated up to 7 days)**

## Add 3 drops buffer to moisten membrane

**Add 3 drops buffer to moisten membrane**

## Run positive and negative control with each test or batch of tests

**Run positive and negative control with each test or batch of tests**

## Add one drop of serum or plasma, followed by 3 drops of buffer.

**Add one drop of serum or plasma, followed by 3 drops of buffer.**

## Add 4 drops of conjugate solution

**Add 4 drops of conjugate solution**

## Add 3 drops of buffer to wash

**Add 3 drops of buffer to wash**

## Read results immediately

**Read results immediately**

**Positive**

**Negative**

## Reveal: Characteristics

- Sensitivity 98.8%
- Specificity:  serum 99.1%   plasma 98.6%
- CLIA: moderate complexity
- Run controls with each test
- Each vial of conjugate, controls sufficient for 5 tests
- Room temperature storage until reconstituted
- More dependent on laboratory facility

## Rapid Test Performance:  Serum

***206 HIV+, 194 HIV- stored sera***

## Confirmatory Testing Required

- For Western blot:
- Venipuncture for whole blood
- Oral fluid specimen
- Immunofluorescence assay

## New Opportunities

**For**
**Confusion**

## Standard EIA

**A color reaction occurs if HIV antibody is present**

## Standard tests:  EIA

**An automated reader gives an accurate measure of optical density (presence of color) for each well**

## Perinatal Screening:  MIRIAD Study

- As of May:
-  3178 women screened
-  27 new HIV infections identified
- 1 false-positive OraQuick; No false-negatives
- 7 false-positive EIAs
- 3 WB negative, 4 WB indeterminate
- 3 false-positive SUDS
*(Theoretical:  27 false-positive Reveal)*

## Challenge: Interpreting HIV Antibody Tests

- 5 FDA-approved EIAs:
- Abbott HIVAB HIV-1/HIV-2 (rDNA)
- Genetic Systems HIV-1/HIV-2 Peptide
- Genetic Systems rLAV HIV-1
- Vironostika HIV-1 Microelisa
- Vironostika HIV-1 plus O Microelisa*

**Approved June 6, 2003*

## HIV Antigens in EIAs

| Abbott HIVAB HIV-1/2 | Gp41, Gp120, Gp36 |
| --- | --- |
| Genetic Systems rLAV | Viral lysate, rGp41 |
| Gen Sys HIV-1/HIV-2  | Gp41, sP32, Gp36 |
| Vironostika HIV-1 Microelisa | Viral lysate |

## Standard Confirmation:  Western blot

**Bands on the Western blot indicate which specific antibodies are present and can vary in intensity.**

## Western Blot Interpretation

- Negative:  *No bands*
- Positive:
*Any two of:  p24, gp41, gp120/gp160*
- Indeterminate:
*Presence of any bands not meeting criteria (frequently, only p24 or p55)*

## What to do?

- Become familiar with the tests that are used
- Choose tests carefully
- Ask for help!

## Additional Resources

- Background information (updated frequently):
**   ****www.cdc.gov/hiv/testing.htm**

## Slide 37