Clinical Evaluation of the Bio-Rad Geenius HIV 1/2 Supplemental Assay. Paul D. Swenson, Ph.D. Laboratory Director Public Health Seattle & King County

Transcription

1 Clinical Evaluation of the Bio-Rad Geenius HIV 1/2 Supplemental Assay Paul D. Swenson, Ph.D. Laboratory Director Public Health Seattle & King County

2 HIV in the United States 1.1 million persons living with HIV infection (2010) 181,000 persons unaware of their infection (2010) 50,000 new infections annually ( ) 83 million adults reported that they had ever been tested (2009)

3 1 st Generation HIV Immunoassay HIV-1 viral lysate antigens are used to bind HIV antibodies Labeled antihuman IgG is used to detect IgG antibodies (indirect format) Significant specimen dilution is required to overcome cross-reactivity with cellular proteins

4 2 nd Generation HIV Immunoassay HIV-1 with or without HIV-2 synthetic peptide or recombinant protein antigens are used to bind HIV antibodies Labeled antihuman IgG is used to detect IgG antibodies (indirect format) Use of synthetic peptide and recombinant protein antigens improves sensitivity for HIV-1 group O and HIV-2 and improves specificity

5 3 rd Generation HIV Immunoassay HIV-1 and HIV-2 synthetic peptide or recombinant protein antigens are used to bind HIV antibodies Labeled synthetic peptide or recombinant protein antigens are used to detect IgM and IgG antibodies (antigen sandwich format) Lower specimen dilution and ability to detect IgM antibodies increase sensitivity during early seroconversion

6 4th Generation HIV Immunoassay HIV-1 and HIV-2 synthetic peptide or recombinant protein antigens are used to bind HIV antibodies Labeled synthetic peptide or recombinant protein antigens are used to detect IgM and IgG antibodies (antigen sandwich format) Monoclonal antibodies are also included to detect HIV-1 p24 antigen to detect HIV-1 infection before seroconversion

7 Laboratory Markers of HIV-1 Infection

8 HIV Testing Algorithm Initiate screening with a HIV-1 antibody EIA Reactive specimens should be tested with a more specific HIV-1 antibody test such as Western blot or IFA

9 HIV Testing Algorithm Initiate screening with a HIV-1/HIV-2 antibody EIA if testing for HIV-2 is indicated Reactive specimens should be tested with a HIV-1 antibody Western blot or IFA Negative or indeterminate specimens should be tested with a HIV-2 antibody EIA Reactive specimens should be tested with a HIV-2 Western blot

10 HIV Testing Algorithm Initiate screening with a rapid HIV-1 antibody test Reactive specimens should be tested with a HIV-1 antibody Western blot or IFA even if an EIA screening test is negative

11 HIV Testing Algorithm Initiate screening with a HIV-1/HIV-2 antigen/antibody combination immunoassay Reactive specimens should be tested with a HIV-1/HIV-2 antibody differentiation immunoassay Negative or indeterminate specimens should be tested with a HIV-1 NAT to detect acute HIV-1 infection Use same algorithm after a reactive rapid test

12 New HIV Testing Algorithm

13 Pooled HIV-1 NAT at PHSKC Pooled NAT has been performed on HIV antibody negative MSM since 2003 to detect acute HIV-1 infection From , 328 of 14,005 MSM specimens were HIV antibody positive and 36 HIV antibody negative specimens were positive by pooled HIV-1 NAT Pooled HIV-1 NAT increased detection of HIV-1 infection by 11% Stekler et al Clin Infect Dis 2009

14 Pooled HIV-1 NAT Today? 4 th generation HIV-1/HIV-2 antigen antibody combination immunoassays detect acute HIV- 1 infections if HIV-1 RNA level is >30,000 copies/ml Pooled HIV-1 NAT detects HIV-1 RNA down to 1,000 copies/ml Pooled HIV-1 NAT detects some acute HIV-1 infections missed by 4 th generation immunoassays

15 HIV-1/HIV-2 Antibody Differentiation Immunoassay Detects HIV-1 earlier than Western blot or IFA Identifies HIV-2 infections; HIV-2 infections are often misclassified as HIV-1 by Western blot Shorter turnaround time than Western blot Lower cost than Western blot

16 Multispot HIV-1/HIV-2 Rapid Test Rapid single use EIA for detection and differentiation of HIV-1 and HIV-2 antibodies in serum or plasma Procedure has 10 steps Completed in 15 minutes Results are read and interpreted visually FDA approved in 2004 and 2013

17 Geenius TM HIV 1/2 Supplemental Assay Rapid single use immunochromatographic test for confirmation and differentiation of HIV-1 and HIV-2 antibodies in fingerstick whole blood, venous whole blood, serum, or plasma Procedure has 3 steps Completed in 30 minutes Results are read and interpreted with the Geenius Reader and dedicated software Under FDA review

18 Geenius System 18

19 Intended Use of Geenius Assay Additional, more specific test to confirm the presence of antibodies to HIV-1 and HIV-2 for specimens found to be repeatedly reactive by screening procedures. An alternative to Multispot for use as part of an HIV-1/HIV-2 diagnostic testing algorithm that includes differentiation of HIV-1 and HIV- 2 antibodies

20 Geenius Protocol 20

21 Geenius Cassette: Technology Dual Path Platform Technology (DPP ) : 21

22 Geenius Technology Dual Path Platform (DPP ) Example : gp160 22

23 Geenius Technology Dual Path Platform (DPP ) Example : gp160 23

24 Geenius Technology Dual Path Platform (DPP ) Example : gp160 24

25 Geenius Technology Dual Path Platform (DPP ) Example : gp160 25

26 Geenius Geenius HIV 1/2 Supplemental cassette utilizes the following HIV peptides and recombinant antigens. HIV-2 HIV-1 Ctl Band GP36 peptide GP140 peptides P31 peptide GP160 recombinant P24 recombinant GP41 peptides ENV ENV POL ENV GAG ENV Protein A 26

27 Geenius Results are determined by the Geenius reader and computer using the following criteria: Criteria Test validation HIV negative sample HIV-1 Positive HIV-2 positive Control band must be present Absence of HIV-1 and HIV-2 bands Presence of at least 2 HIV-1 bands including at least one ENV (GP160 or gp41) Presence of both GP140 and GP36 HIV-2 bands Indeterminate sample Presence of HIV-1 or HIV-2 band(s) which not meet HIV-1 or HIV-2 positivity criteria

28 Geenius Reactivity in HIV-1 Seroconversion Panels Seroconversion sensitivity with 26 seroconversion panels with 157 RNA positive panel members Geenius is 27% (71 vs. 56) more sensitive than Western blot Geenius is 9% (71 vs. 65) more sensitive than Multispot

29 Geenius

30 Clinical Evaluation of Geenius Assay Prospective samples collected from 136 known HIV-1 positive/aids patients at UW ACTU Samples included 136 serum, 136 whole blood (74 EDTA, 62 heparin), and 74 fingerstick Geenius testing on fingerstick samples performed at UW ACTU Geenius testing on serum, whole blood, and plasma performed at PHSKC Laboratory Reference testing on serum at PHSKC Laboratory

31 Geenius Known HIV-1/AIDS Positive Population