Rapid Testing Algorithm Performance in a Low-Prevalence Environment.

BACKGROUND: The performance of a statewide HIV rapid test algorithm (RTA) in a low-prevalence setting (0.71%) was examined for 3 years. METHODS: An initial rapid screening by HIV-1/2 Ag/Ab Combo test (RT#1) with Ab verification using a second, different rapid test (RT#2) was conducted. Clinic referral was immediate for antigen-only-positive screens. Antibody-positive screens were confirmed by RT#2. Specimens were collected following discordant RTA results (initially Ab-POS by RT#1, but negative on RT#2) and tested in accordance with the current Centers for Disease Control and Prevention/Association of Public Health Laboratories-based HIV diagnostic algorithm supplemented by a quantitative viral load whenever possible. RESULTS: Of 310,785 tests performed, 2400 preliminary positive screens were identified; 2191 (91.8%) confirmed by RT#2. Of 13 Determine Combo AG-POS results identified, only 1 confirmed positive. Of the remaining 196 discordant results, 182 (92.9%) were uninfected, including 13 with AG-POS/AB-POS results. Of 14 true positives (7.1%) identified after discordant RTA results, the average quantitative HIV-1 viral load was 277,385 copies/mL, but 5 (35.7%) of 14 had viral loads <1000 copies/mL. Among the 2191 "presumptive positive" by RTA, 3 false-positive (FP) RTAs were reported (both rapid tests having positive results, while the HIV-1/2 Ag/Ab assay and quantitative HIV-1 viral load showed negative results). CONCLUSIONS: The RTA was effective in predicting true-positive HIV test results and facilitating linkage to care. Discordant results were infrequent. Fingerstick DC Ag detection identified a single early infection. Many discordant cases that were subsequently positive were associated with viral loads <1000 copies/mL.

Finding those at risk: acute HIV infection in Newark, NJ.

BACKGROUND: A screening strategy combining rapid HIV-1/2 (HIV) antibody testing with pooled HIV-1 RNA testing increases identification of HIV infections, but may have other limitations that restrict its usefulness to all but the highest incidence populations. OBJECTIVE: By combining rapid antibody detection and pooled nucleic acid amplification testing (NAAT) testing, we sought to improve detection of early HIV-1 infections in an urban Newark, NJ hospital setting. STUDY DESIGN: Pooled NAAT HIV-1 RNA testing was offered to emergency department patients and outpatients being screened for HIV antibodies by fingerstick-rapid HIV testing. For those negative by rapid HIV and agreeing to NAAT testing, pooled plasma samples were prepared and sent to the University of Washington where real-time reverse transcription-polymerase chain reaction (RT-PCR) amplification was performed. RESULTS: Of 13,226 individuals screened, 6381 had rapid antibody testing alone, and 6845 agreed to add NAAT HIV screening. Rapid testing identified 115 antibody positive individuals. Pooled NAAT increased HIV-1 case detection by 7.0% identifying 8 additional cases. Overall, acute HIV infection yield was 0.12%. While males represent only 48.1% of those tested by NAAT, all samples that screened positive for HIV-1 RNA were obtained from men. CONCLUSION: HIV-1 RNA testing of pooled, HIV antibody-negative specimens permits identification of recent infections. In Newark, pooled NAAT increased HIV-1 case detection and provided an opportunity to focus on treatment and prevention messages for those most at risk of transmitting infection. Although constrained by client willingness to participate in testing associated with a need to return to receive further results, use of pooled NAAT improved early infection sensitivity.

Cost effectiveness analysis of the New Jersey rapid testing algorithm for HIV testing in publicly funded testing sites.

BACKGROUND: Before 2009, New Jersey (NJ) publicly funded counseling and testing sites (CTS) tested for HIV using a single rapid test followed, when positive, by a Western Blot (WB) for confirmation. With this strategy, 74.8% of confirmed positive clients returned to receive test results. To improve the client notification rate at these centers, the New Jersey (NJ) Division of HIV, STD and TB Services (DHSTS) implemented a rapid testing algorithm (RTA) which utilizes a second, different, rapid test to verify a preliminary positive. OBJECTIVE: To compare the cost-effectiveness of the two testing algorithms. STUDY DESIGN: This was a retrospective cost-effectiveness analysis. DATA SOURCES: New Jersey HIV Rapid Testing Support Program (NJHIV) records, DHSTS grant documents, counseling time estimates from an online survey of site supervisors. Costs included test kits and personnel costs from month of RTA implementation through 11/30 in 2008 and 2009. The incremental cost of the RTA was calculated per additional percent of positive clients who were notified and per day earlier notification. RESULTS: In 2008, 215 of 247 clients with a positive rapid HIV test were confirmed positive by WB. 90.9% of clients were notified a mean of 11.4 days after their initial test. 12 refused confirmatory WB. In 2009, 152 of 170 clients with one positive rapid test had a confirmatory second positive rapid test and were notified on the same day. The incremental cost of the RTA was $20.31 per additional positive person notified and $24.31 per day earlier notification or $3.23 per additional positive person and $3.87 per day earlier notification if the WB were eliminated. CONCLUSIONS: The RTA is a cost-effective strategy achieving 100% notification of newly HIV positive clients a mean of 11.4 days earlier compared to standard testing.

Use of a rapid HIV testing algorithm to improve linkage to care.

BACKGROUND: Awaiting definitive diagnosis before scheduling healthcare visits complicates HIV screening and referral. Clients screened by rapid tests as initially reactive often fail to return to receive definitive test results, are not linked to care and enter care late or not at all. OBJECTIVES: To evaluate statewide, (1) the accuracy of a single-visit, two test HIV rapid testing algorithm (RTA) and (2) its effect on referral to care for positive clients. STUDY DESIGN: A two-test RTA was implemented at 24 sites in New Jersey beginning in December 2008. All clients with a reactive rapid HIV test were offered a second rapid HIV test, and RTA results were compared with Western blot (WB). Referral to care occurred based upon two sequential positive rapid tests. RESULTS: The RTA program has screened 51,413 individuals obtaining 426 reactive rapid test results; 394 (92.5%) were reactive by a second rapid test, 32 (7.5%) had a negative second rapid test. Twenty-eight individuals refused WB testing. Of 369 RTA-positive individuals who have WB results, 368 (99.5%) were confirmed positive. Of RTA-positive clients, 290 (73.6%), including 25 (6.6%) who refused Western blot, were immediately referred for care including one individual with a false-positive RTA. CONCLUSIONS: The RTA reduced false positive results by 6.2% and agreed with WB results 99.5% of the time. Improved referral to care compared to traditional rapid HIV screening occurs when immediate referral is based on RTA verification of a preliminary positive rapid test. WB confirmation is not essential for effective screening and contributes to difficulties linking individuals to care.

Rapid human immunodeficiency virus test quality assurance practices and outcomes among testing sites affiliated with 17 public health departments.

Rapid human immunodeficiency virus testing is often conducted in nonclinical settings by staff with limited training, so quality assurance (QA) monitoring is critical to ensure accuracy of test results. Rapid tests (n = 86,749) were generally conducted according to manufacturers' instructions, but ongoing testing competency assessments and on-site QA monitoring were not uniformly conducted.

Investigation of false positive results with an oral fluid rapid HIV-1/2 antibody test.

BACKGROUND: In March 2004, the OraQuick rapid HIV antibody test became the first rapid HIV test approved by the US Food and Drug Administration for use on oral fluid specimens. Test results are available in 20 minutes, and the oral fluid test is non-invasive. From August 2004-June 2005, we investigated a sudden increase in false-positive results occurring in a performance study of OraQuick oral-fluid rapid HIV tests in Minnesota. METHODOLOGY/PRINCIPAL FINDINGS: In a field investigation, we reviewed performance study data on oral-fluid and whole-blood OraQuick rapid HIV test device lots and expiration dates and assessed test performance and interpretation with oral-fluid and whole-blood specimens by operators who reported false-positive results. We used multivariate logistic regression to evaluate client demographic and risk characteristics associated with false-positive results. Next, we conducted an incidence study of false-positive OraQuick rapid HIV tests in nine US cities and tested both oral-fluid and finger-stick whole-blood specimens from clients; reactive tests were confirmed with Western blot. Sixteen (4.1%) false-positive oral-fluid results occurred in the performance study from April 15, 2004 through August 31, 2004 with unexpired devices from six test lots among 388 HIV-uninfected clients (specificity, 95.9%; 95% CI: 93.4-97.6). Three test operators who had reported false-positive results performed and interpreted the test according to package-insert instructions. In multivariate analysis, only older age was significantly associated with false-positive results (adjusted odds ratio = 4.5, 95% CI: 1.2-25.7). In the incidence study, all valid oral-fluid and whole-blood results from 2,268 clients were concordant and no false-positive results occurred (100% specificity). CONCLUSIONS/SIGNIFICANCE: The field investigation did not identify a cause for the increase in false-positive oral-fluid results, and the incidence study detected no false-positive results. The findings suggest this was an isolated cluster; the test's overall performance was as specified by the manufacturer.