# Presentation: 728165

## ARC Experience with Indeterminate Blood Donors

- E001372A

***ARC Experience with Indeterminate Blood Donors***

- Susan L. Stramer, Ph.D.National Confirmatory Testing LaboratoryAmerican Red Cross

## Outline

- Definition of HIV-1 Western Blot Indeterminate and “Non-Viral” Bands
- Regulatory Consequences of Ignoring “Non-Viral” Bands
- Current Frequency of Indeterminates and “Non-Viral” Bands (1998-1999 ARC Data)
- Integration of NAT Results with Indeterminate Interpretations

## Cambridge BiotechHuman Immunodeficiency Virus Type 1 (HIV -1)Western Blot Kit

- Any bands present but pattern does not meet criteria for POSITIVE = INDETERMINATE
- Non-viral bands have been observed with certain specimens. These bands are not usually accompanied by any of the major viral bands of diagnostic significance (p24, gp41/120/160). The non-viral bands appear to be cell related with the most common in the molecular weight range of 70K, 51-55K (possible HLA-DR) and 43K (possible HLA-ABC).

## APHL 14th Annual Conference on Human Retrovirus Testing – Conference Report, 1999

- The interpretation of indeterminate should **not** include reporting non-viral bands (e.g., p70). The rationale for this is that since 1991 no individual exhibiting non-viral banding has been associated with either seroconversion, detection of different HIV-1 subtypes or other disease agents. **Only viral bands that are specified in the package insert ranging from molecular weights ****p17 to gp160 should be reported.**

## Regulatory Consequences of Ignoring “Non-Viral” Bands

- Between March 1989 and September 1993, a total of 621 samples were reported as negative by ARC when there was evidence of a band p70
- 460 repeat reactive index donations (HIV-1 EIA)
- 161 reentered donors
- Resulted in multimillion dollar recall of “safe” products
- None of reentered donors (with hundreds of subsequent donations over the four year period) demonstrated any evidence of HIV seroconversion

## HIV-1 Blood Donor Screening/SupplementalTest Results (ARC)

- 12.4 Million Donations Screened

- Positive
- 791 (7.1%)

- Negative
- 5,128 (46.3%)

- Indeterminate
- 5,161 (46.6%)

**1998-1999**

- 11,080 Repeat Reactive (0.09%)HIV-1 WB (Cambridge Biotech)

## HIV-1/2 Testing by Month – 1999

**Interp****	**** N****	****%****	****Avg/Month**

**	****Neg****	**2,600	48.1	216.7
**	****Ind****	**2,401	44.5	200.1
**	****Pos****	**400	7.4	33.3
**	****Total****	**5,401		450.1

- Month (1999)

- Number

***HIV-1/2 Testing by Month – 1999***

## HIV-1 Blood Donor Screening/SupplementalTest Results (ARC) (Cont.)

- 5,161 Indeterminate (46.6%)

- One
- Viral
- Band

- 2,752 (53.3%)

- Multiple
- Viral
- Bands

- 589 (11.4%)

- BackgroundOnly
- (obscures
- reading)

- 1,050 (20.3%)

- Non-
- ViralBands

- 724 (14%)

- 16 (35%)“ENV” only

- 1,925 (70%)p24 “GAG” only

- 464 (79%) “GAG” reactivity with or without other banding

- 569 (79%)“p70”

- 65.7% Viral Banding

**1998-1999**

## HIV-1 Blood Donor Screening/Supplemental/NATTest Results (ARC)

- Positive

- Negative

- Indeterminate

**9/8/99 – 12/31/99**

- 1,836 Repeat Reactive (0.09%)HIV-1 WB (Cambridge Biotech)

- 2.0 Million Donations Screened

- 71 (3.9%)

- 824 (44.9%)

- 941 (51.2%)

**67 (94.4%)**

**1 (0.1%)**

**0**

**No. HIV**
**NAT Rx:**

- 4 HIV NAT Neg (“ENV” Only WB)

- p24 Only WB S/CO EIA = 11.62S/CO NAT = 18.23

## HIV-1 Blood Donor Screening/Supplemental/NATTest Results (ARC) (Cont.)

- 824 Indeterminate (44.9%)

- One
- Viral
- Band

- 460 (55.8%)

- Multiple
- Viral
- Bands

- 91 (11.0%)

- BackgroundOnly
- (obscures
- reading)

- 154 (18.7%)

- Non-
- ViralBands

- 108 (13.1%)

- 341 (74.1%)p24 “GAG” only

- 72 (79%) “GAG” reactivity with or without other banding

- 78 (72%)“p70”

**0**

**No. HIV**
**NAT Rx:**

**1**

**0**

**0**

**0**

**9/8/99 – 12/31/99**

## HIV-1 RNA Concentrations During SC Based on NGI’s PCR of 28 Plasma Donor Panels (N=221) 

***HIV-1 RNA Concentrations During SC Based on ******NGI’s PCR of 28 Plasma Donor Panels (N=221) ***

- PCR–/Ag–/Ab–(n=19)

- PCR+/Ag–/Ab–(n=22)

- PCR+/Ag+/Ab–(n=22)

- PCR+/Ag+/–/IgM+/IgG–WB–/IND(n=19)

- PCR+/Ag+/–/IgM+/IgG–WB POS(n=12)

- Categories

- 6

- Median Days

- 6

- PCR+/Ag+/–/Ab+(n=20)

- 0

- 7

- 3

- 4

- HIV-1 RNA Copies/mL

- E001372A

## HIV-1 Viral Load in Indeterminate SamplesFrom Seroconverting Donors

- 41 samples, all NAT reactive,no non-viral bands reported

- p24 Ag Reactivity

- 29 (+)

- 19 (–)
- 4,7503,500-75,000(4 samples = 200-400 copies/mL)

- 90% (37/41) detected with pool testing at a cutoff of 1,600-2,400 copies/mL

- Median copies/mL:	800,000Range:	5,500-1,000,000

- 4,7503,500-75,000(4 samples = 200-400 copies/mL)

## Comparison of HIV-1 p24 Ag PositiveWindow-Case U.S. Blood Donors

***Comparison of HIV-1 p24 Ag Positive******Window-Case U.S. Blood Donors***

- 1	Index	**6 x 10****5*******	**14.0***	95	0.1		12	**3 x 10****4**	**1.2**	95	**2.3**	POS – minus p31	22	**1 x 10****5**	0.3	 	**5.6**	POS – all bands
- 2	Index	**2 x 10****6*******	**28.5***	94	0.8		20	**1 x 10****5**	0.7	 	**1.6**	POS – minus p31	43	**1 x 10****4**	0.1	 	**5.3**	POS – all bands
- 3	Index	**1 x 10****5**	**8.1**	95	0.1		13	**5 x 10****5*******	**26.5***	90	**8.8**	POS – minus p31
- 4	Index	**1 x 10****5**	**2.4**	95	0.0		13	**1 x 10****6*******	**17.5***	89	**2.7**	IND – p66	75	**5 x 10****4**	0.1	 	**17.4**	POS – all bands
- 5	Index	**3 x 10****5**	**18.6***	99	0.3		10	**4 x 10****5*******	0.2		**4.3**	POS – minus p31	17	**1 x 10****5**	0.9	 	**12.5**	POS – minus p31	24	**3 x 10****4**	0.7	 	**8.5**	POS – minus p31	31	**2 x 10****4**	0.1	 	**13.1**	POS – minus p31

**SC**

**Sample ****Collection****(days)**

**WB**

**RNA ****Copies/mL**

**p24 Ag ****S/CO**

**Percent****Neut.**

**HIV-1/****HIV-2 Ab ****S/CO**

## E001372A <number>

- E001372A

## E001372A <number>

- E001372A

## Cambridge Biotech HIV-1 Western Blot

***Cambridge Biotech HIV-1 Western Blot***

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Cambridge Biotech HIV-1 Western Blot

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Cambridge Biotech HIV-1 Western Blot

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Cambridge Biotech HIV-1 Western Blot

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Cambridge Biotech HIV-1 Western Blot

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Cambridge Biotech HIV-1 Western Blot

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Cambridge Biotech HIV-1 Western Blot

- gp160

- gp120

- p66

- p55/51

- gp41

- p31

- p24

- p17

## Summary and Conclusions

- Due to manufacturer’s requirements, samples with non-viral bands must be reported as “indeterminate”
- Non-viral bands are:
- “Just that”
- Do not indicate presence of any virus, past, present or future
- Donors with non-viral bands represent 14% of total indeterminates and are otherwise “safe” donors (RNA negative)
- HIV-1 viral loads in seroconverting individuals with viral indeterminate patterns exceed the cutoff of pooled NAT testing (90% of cases); none with non-viral patterns
- Patterns of non-viral bands do **not** resemble any pattern seen in early HIV-1 seroconversion