The following tables summarize the aggregate results from the prospective, cross-sectional, voluntary testing population of unknown HIV status as well as those with known HIV-1 infection tested in POC and laboratory settings through June 30, 2004:

Table 1: POC INSTI™ results compared to PHL-based Abbott AxSym, n=3507

Abbott Axsym
	Positive	Negative	Indeterminate
POC INSTI™ Positive	817	181	12
POC INSTI™ Negative	133	2478	14
POC INSTI™ Invalid	38	141	0

1. All 18 are considered INSTI POC false positive.
2. Sample B1B0031. Possible early seroconversion.
3. 10/13 considered Axsym false positive.
4. Sample initially positive on Axsym, but negative 2X on repeat. WB shows weak bands at p24 and p65 only.

Sensitivity of POC INSTI™: 99.6% (817/820, 95% CI: 98.9 - 99.9%); PPV: 97.8%
Specificity of POC INSTI™: 99.3% (2488/2506, 95% CI: 98.9 - 99.5%); NPV: 99.5%

Table 2: PHL INSTI™ on whole blood (EDTA) compared to PHL-based Abbott AxSym, n=3481

Abbott Axsym
	Positive	Negative	Indeterminate
POC INSTI™ Positive	831	91	12
POC INSTI™ Negative	153	2611	14
POC INSTI™ Invalid	10	3	0

1. All 9 are considered INSTI false positive
2. Sample B1B0031, possible early seroconversion.
3. 10/15 considered Axsym false positive
4. Sample initially positive on Axsym, but negative 2X on repeat. WB shows weak bands at p24 and p65 only.

Sensitivity of POC INSTI™: 99.4% (831/836, 95% CI: 98.6 – 99.7%); PPV: 98.9%
Specificity of POC INSTI™: 99.7% (2621/2630, 95% CI: 99.4 – 99.8%); NPV: 99.9%

Table 3: PHL INSTI™ on plasma compared to PHL-based Abbott Axsym, n=3479

Abbott Axsym
	Positive	Negative	Indeterminate
POC INSTI™ Positive	834	11	0
POC INSTI™ Negative	143	2627	23
POC INSTI™ Invalid	1	0	0

1. Sample B3B 0240, considered INSTI blood and plasma false positive. See Table of Discordant Results.
2. 10/14 considered Axsym false positive
3. Sample B1B0031, possible early seroconversion. Sample B1B0568: Axsym initially positive, but neg 2X on repeat. WB shows weak bands at p24 and p65 only.

Sensitivity of POC INSTI™: 99.5% (834/836, 95% CI: 98.8 – 99.8%); PPV: 99.9%
Specificity of POC INSTI™: 100% (2627/2628, 95% CI: 99.8 – 100%); NPV: 99.9%

Table 4: PHL INSTI™ on serum compared to PHL-based Abbott Axsym, n=1346

Abbott Axsym
	Positive	Negative	Indeterminate
POC INSTI™ Positive	392	0	0
POC INSTI™ Negative	41	949	0
POC INSTI™ Invalid	1	0	0

1.  Samples considered early seroconversion; INSTI positive on whole blood

Sensitivity of POC INSTI™: 99.5% (392/396, 95% CI: 97.4 – 99.6%); PPV: 100%
Specificity of POC INSTI™: 100% (949/949, 95% CI: 99.6 – 100%); NPV: 99.6%

Seroconversion Panels
Relative sensitivity of INSTI™ compared to approved EIA methods for detection of antibodies in Commercial (BBI) Seroconversion Panels (n=25)

INSTI™	Number of Panels
Detected earliest bleed of panel	14
Within 1 bleed of earliest EIA positive	81
Within 2 bleed of earliest EIA positive	12
Unknown	23

1. INSTI positive on panel samples collected 3-8 days following the earliest positive EIA
2. INSTI positive on panel sample collected 7 days after the earliest positive EIA
3. The last bleed in the panel was positive by at least 1 EIA, negative by INSTI. Anti-HIV-1 Seroconversion Panels PrB937 and PRB938

HIV-2 Detection, n=49
All 49 frozen (-20C) serum samples were confirmed positive for HIV-2 antibodies by Western Blot (New Lav Blot HIV-2 (Biorad).
49/49 were positive with the INSTI™ HIV-1/HIV-2* rapid antibody test (100% sensitivity).
All INSTI™ and HIV-2 testing was conducted at the Laboratoire de Virologie, C.E.R.V.I., G.H. Pitie- Salpetriere, Paris, France.

Discussion and Conclusions

The INSTI™ HIV-1/HIV-2* rapid antibody test in POC settings as well as laboratory testing sites was equivalent to the Health Canada approved laboratory test of record (Abbott AxSym GO) in overall sensitivity, specificity, and early antibody detection. Performance characteristics of INSTI™ were highly concordant across matching finger-stick blood, venous whole blood (EDTA), plasma and serum. There was no INSTI™ lot-to-lot variation in performance observed. Work is continuing for HIV- 2 performance characteristics. Invalid results were more frequent at POC sites, and tended to be the result of sub-optimal amounts of blood collected with the disposable transfer pipette included in the kit. This is evidence that the INSTI™ test device will only work with the addition of adequate amounts of human IgG, providing a high degree of patients safety in validity of results.

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