1 / 18

Comparison of the HIV LIA vs WB on HIV-Negative Samples

Comparison of the HIV LIA vs WB on HIV-Negative Samples. CDC-HIV Diagnostics Meeting “New Diagnostic Technologies” Dec 5-7, 2007 Dr. John Kim National Laboratory for HIV Reference Services Public Health Agency of Canada Ottawa, Ontario. sample. EIA. non-reactive. REPORT. screening.

lawrence-oneill
Download Presentation

Comparison of the HIV LIA vs WB on HIV-Negative Samples

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Comparison of the HIV LIA vs WB on HIV-Negative Samples CDC-HIV Diagnostics Meeting “New Diagnostic Technologies” Dec 5-7, 2007 Dr. John Kim National Laboratory for HIV Reference Services Public Health Agency of Canada Ottawa, Ontario

  2. sample EIA non-reactive REPORT screening Repeat reactive confirmatory (a) Western blot (HIV-1) (b) RIPA (HIV-1, HIV-2) (C) LIA (HIV-1/HIV-2) Final Diagnosis (d) PCR –Roche, Hpol, gp41, HIV-2 RNA – bDNA, Roche, Abbott, HIV-2 Q Figure 1. HIV Testing (general)

  3. Positive Predictive Values (Importance of Supplementary Tests) Prevalence EIAEIA + WB 0.02 % 9% 89.3 %* 0.04 % 16.7 % 95.2 % 0.40 % 66.7 % 99.5 % 1.0 % 83.5 % 99.8 %

  4. INNO-LIA HIV (new technology ?) • New anti-human immunodeficiency virus immunoblot assays resolve non-specific Western blot results. (Zaaijer et al, Transfusion, 37:193, 1997). • Validation of a new immunoblot assay for confirmation of human immunodeficiency virus infection (Zaaijer et al, Transfusion, 38:776, 1998). • Ability of the Innogenetics Inno-Lia to distinguish HIV-1, HIV-2 and dually reactive sera. (Granade et al, Abstr. Gen Meet Am Soc Microbiol, 92:416 [T-47[, 1992. • Confirmation of HIV infection with the line immune assay (INNO-LIA) using whole blood impregnated filter paper discs. (Kestens et al, Abstr. Int Conf Aids 5:309 [TBP 135], 1989.

  5. p31 p17 Detection of non-Subtype B HIV reference samples on Subtype B HIV-1 (WB & LIA) antigen kits “O” ? A D C E F F + “O” ? A D C E F F 2 2 gp160 gp120 gp41 HIV-1 HIV-2 p24

  6. gp41 p31 p24 p17 HIV-2 Reference Samples and atypical HIV-1 WB Patterns 1 2 3 4 5 6 7 gp160 1 2 3 4 5 6 7 gp120 HIV-1 HIV-2

  7. HIV WB Quality ISSUES-Canada

  8. Methods • BIO-RAD Wb vs INNOGenetics HIV 1/2 Score • > 1000 samples, (2002-2007) • n=823 (77-pos; 746-neg), final status known/WB-LIA results • Neg samples (746) • n=472, LIA-neg/Wb-neg • n=232*, LIA-neg/Wb-ind • n=42, LIA-ind/Wb-ind [23],LIA-ind/Wb-neg [15], • LIA-pos/Wb-pos/neg/ind [4]

  9. NLHRS n=823 positive negative 73 258 positive TP FP Wb 4 488 negative FN TN HIV Wb vs NLHRS sens – 73/(73 +4)= 95% spec – 488/(488+258)= 65% PPV – 73/(73 +258)= 22% NPV – 488/(488+4)= 99%

  10. NLHRS n=823 positive negative 77 42 positive TP FP LIA 0 704 negative FN TN HIV LIA vs NLHRS sens – 77/(77 +0)= 100% spec – 704/(704+42)= 94% PPV – 77/(77 +42)= 65% NPV – 704/(704+0)= 100%

  11. Comparison of WB vs LIA Patterns on HIV-Negative Samples (NLHRS)

  12. HIV-1 WB (BIO-RAD) gp 160 gp 120 p66 p55 p51 gp 41 p31 p24 p17 HIV-1 gp 120 gp 41 p31 p24 p17 gp 105 gp 36 INNO-LIA – HIV 1&2 HIV-1 HIV-2

  13. HIV-1 WB (BIO-RAD) gp 160 gp 120 p66 p55 p51 gp 41 p31 p24 p17 HIV-1 gp 120 gp 41 p31 p24 p17 gp 105 gp 36 INNO-LIA – HIV 1&2 HIV-1 HIV-2

  14. HIV-1 WB (BIO-RAD) gp 160 gp 120 p66 p55 p51 gp 41 p31 p24 p17 HIV-1 gp 120 gp 41 p31 p24 p17 gp 105 gp 36 INNO-LIA – HIV 1&2 HIV-1 HIV-2

  15. Living with the Wb-Improvements • Wb still most widely used (licensed) confirm tool • Known for years (89.3% [266/298]; BIORad; p20) • Review/Change interpretative criteria…Harmonize international criterias • Combine wb interpretative criteria • eg: CDC/ASTPHLD + WHO [Tebourski et al, 2004] • License new tests (eg. LIA) – patent issues ? • LIA – test of choice in NLHRS • sens (100% vs 95%), spec (94% vs 65%) • PPV (65% vs 22%), NPV (100% vs 99%)

  16. % False Positives OMIT SLIDE ? % Prevalence

  17. Predictive Values OMIT SLIDE ??? Positive predictive value (PPV) PPV = TP/TP +FP (x 100) Negative predictive value (NPV) NPV = TN/TN+FN (x100) How accurately a test predicts the presence or absence of analyte (disease) ! (i) sensitivity - incidence of true positives in those with disease (ii) specificity - incidence of true of negatives in those without disease (iii) prevalence - number of actual cases (of disease) in the population. Galen RS and Gambino SR. Beyond Normality: The Predictive Value and Efficiency of Medical Diagnosis. New York: Wiley, 1975.

More Related