Berry Bennett

Detecting Acute Human Immunodeficiency Virus Infection Using 3 Different Screening Immunoassays and Nucleic Acid Amplification Testing for Human Immunodeficiency Virus RNA, 2006-2008

BACKGROUND The yield of nucleic acid amplification testing (NAAT) after routine screening for human immunodeficiency virus (HIV) antibody to detect acute HIV infection (AHI) may vary with different HIV-antibody assays. METHODS From April 24, 2006, through March 28, 2008, patients underwent routine HIV-antibody screening using a first-generation assay at 14 county sexually transmitted disease (STD) clinics and 1 community clinic serving homosexual patients in Los Angeles; using a second-generation rapid test at 3 municipal STD clinics in New York; and using a third-generation assay at 80 public health clinics in Florida. To identify AHI, seronegative specimens were pooled for NAAT, followed by individual NAAT of specimens with positive findings. All AHI samples screened by first- and second-generation assays also underwent third-generation testing. RESULTS We screened 37 012 persons using NAAT after first-generation testing; 35 AHIs were identified, increasing HIV case detection by 8.2%. After a second-generation rapid test, 6547 persons underwent NAAT; 7 AHIs were identified, increasing HIV case detection by 24.1%. After third-generation testing, 54 948 persons underwent NAAT; 12 AHI cases were identified, increasing HIV case detection by 1.4%. Overall, pooled NAAT after negative third-generation test results detected 26 AHI cases, increasing HIV case detection by 2.2%. Most of the AHI cases from Los Angeles (26 of 35 [74%]) were identified at the community clinic where NAAT after third-generation testing increased HIV case detection by 11.9%. CONCLUSIONS Pooled NAAT after third-generation testing increases HIV case detection, especially in venues of high HIV seropositivity. Therefore, targeted AHI screening using pooled NAAT after third-generation testing may be most effective, warranting a cost-benefit analysis.

Cost-Effectiveness of Pooled Nucleic Acid Amplification Testing for Acute HIV Infection after Third-Generation HIV Antibody Screening and Rapid Testing in the United States: A Comparison of Three Public Health Settings

Angela Hutchinson and colleagues conducted a cost-effectiveness analysis of pooled nucleic acid amplification testing following HIV testing and show that it is not cost-effective at recommended antibody testing intervals for high-risk persons except in very high-incidence settings.

Rapid HIV screening: Missed opportunities for HIV diagnosis and prevention

BACKGROUND Although rapid HIV tests increase the number of persons who are aware of their HIV status, they may fail to detect early HIV infection. OBJECTIVES To evaluate the sensitivity for early HIV infection of several rapid tests and third- and fourth-generation assays compared with nucleic acid amplification testing (NAAT). STUDY DESIGN Sensitivity for early HIV infection was evaluated using 62 NAAT-positive/WB-negative or indeterminate specimens from the CDC Acute HIV Infection study. Specimens underwent third-generation testing with Genetic Systems 1/2+O(®) and rapid testing with Multispot HIV-1/HIV-2. A subset was also tested with four FDA-approved rapid tests and Determine HIV-1 Antigen/Antibody Rapid Test(®) and Architect HIV Antigen/Antibody Combo(®), both fourth-generation tests. RESULTS Of 99,111 specimens screened from April 2006 to March 2008, 62 met the definition for early HIV infection (60 NAAT-positive/seronegative and 2 NAAT-positive/Western blot indeterminate). Third-generation testing correctly detected antibody in 34 specimens (55%; 95% confidence interval (CI): 42-67); Multispot detected antibody in 16 (26%; 95% CI: 16-38). Of the 62 specimens, 33 (53%) had sufficient quantity for further testing. Rapid test sensitivities for early HIV infection ranged from 22-33% compared with 55-57% for the third-generation assay and 76-88% for the fourth-generation tests. CONCLUSIONS Many rapid HIV tests failed to detect half of the early HIV infection cases in whom antibody was present. Programs that screen high-incidence populations with rapid tests should consider supplemental testing with NAAT or other antigen-based tests. These data support the need for more sensitive antigen-based point-of-care screening tests for early HIV infection.

Costs and outcomes of laboratory diagnostic algorithms for the detection of HIV

BACKGROUND An alternative HIV testing algorithm, designed to improve the detection of acute and early infections and differentiate between HIV-1 and HIV-2 antibodies, has been developed by the Centers for Disease Control and Prevention and the Association of Public Health Laboratories. While it promises greater sensitivity, it also raises concerns about costs. OBJECTIVE We sought to compare the most commonly used algorithm which was developed in 1989, a third-generation (3G) immunoassay (IA) and Western blot confirmatory test, to a newer algorithm. The new algorithm includes either a 3G or a fourth-generation (4G) initial IA, followed by confirmatory testing with a HIV-1/HIV-2 differentiation IA and, if needed, a nucleic acid amplification test (NAT). STUDY DESIGN We conducted an analysis of HIV testing costs from the perspective of the laboratory, and classified costs according to IA testing volume. We developed a decision analytic model, populated with cost data from 17 laboratories and published assay performance data, to compare the cost-effectiveness of the testing algorithms for a cohort of 30,000 specimens with a 1% HIV prevalence and 0.1% acute HIV infection prevalence. RESULTS Costs were lower in high-volume laboratories regardless of testing algorithm. For specimens confirmed positive for HIV antibody, the alternative algorithm (IA, Multispot) was less costly than the current algorithm (IA, WB); however, there was wide variation in reported testing costs. For our cohort, the alternative algorithm initiated with a 3G IA and 4G IA identified 15 and 25 more HIV infections, respectively, than the 1989 algorithm. In medium-volume laboratories, the 1989 algorithm was more costly and less effective than the alternative algorithm with a 3G IA; in high-volume laboratories, the alternative algorithm with 3G IA costs

Performance of the Aptima HIV-1 RNA Qualitative Assay with 16- and 32-Member Specimen Pools

162 more per infection detected. The alternative algorithm with 4G instead of 3G incurred an additional cost of

Use of rapid HIV assays as supplemental tests in specimens with repeatedly reactive screening immunoassay results not confirmed by HIV-1 Western blot

14,400 and

Laboratory testing for the diagnosis of HIV infection : updated recommendations

4865 in medium- and high-volume labs, respectively. DISCUSSION HIV testing costs varied with IA testing volumes. The additional cost of 4G over 3G IA might be justified by the additional cases of HIV detected and transmissions averted due to earlier detection. CONCLUSION The alternative HIV testing algorithm compares favorably to the 1989 algorithm in terms of cost and effectiveness.

Performance of the new HIV-1/2 Diagnostic Algorithm in Florida's public health testing population: A review of the first five months of utilization

ABSTRACT The Aptima HIV-1 RNA qualitative assay tested with a WHO-approved HIV type 1 RNA standard in 16- and 32-member pools detected 100% of the pools (1,070 and 2,130 HIV-1 RNA copies/ml/pool, respectively), thus exceeding the FDA-required lower limit of detection. The Aptima test can be used to screen for acute-phase HIV infection.

HIV single staging algorithm: Integration and maximization of resources by reducing time between HIV diagnosis and treatment

BACKGROUND An alternate HIV testing algorithm has been proposed which includes a fourth-generation immunoassay followed by an HIV-1/HIV-2 antibody differentiation supplemental test for reactive specimens and a nucleic acid test (NAT) for specimens with discordant results. OBJECTIVE To evaluate the performance of five rapid tests (Alere Clearview, Bio-Rad Multispot, OraSure OraQuick, MedMira Reveal, and Trinity Biotech Unigold) as the supplemental antibody assay in the algorithm. STUDY DESIGN A total of 3273 serum and plasma specimens that were third-generation immunoassay repeatedly reactive and Western blot (WB) negative or indeterminate were tested with rapid tests and NAT. Specimens were classified by NAT: (1) HIV-1 infected (NAT-reactive; n=184, 5.6%), (2) HIV-status unknown (NAT nonreactive; n=3078, 94.2%) or by Multispot, (3) HIV-2 positive (n=5), and (4) HIV-1 and HIV-2 positive (n=6). Excluding HIV-2 positive specimens, we calculated the proportion of reactive rapid tests among specimens with reactive and nonreactive NAT. RESULTS The proportion of infected specimens with reactive rapid test results and negative or indeterminate WB ranged from 30.4% (56) to 47.8% (88) depending on the rapid test. From 1% to 2% of NAT-negative specimens had reactive rapid test results. CONCLUSIONS In these diagnostically challenging specimens, all rapid tests identified infections that were missed by the Western blot, but only Multispot could differentiate HIV-1 from HIV-2. Regardless of which rapid test is used as a supplemental test in the alternative algorithm, false-positive algorithm results (i.e., reactive screening and rapid test in uninfected person) may occur, which will need to be resolved during the baseline medical evaluation.