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

J Clin Virol. 2013 Sep;58(1):240-4. doi: 10.1016/j.jcv.2013.06.019. Epub 2013 Jul 6.

Abstract

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.

Keywords: Algorithm; Diagnosis; HIV; IA; NAT; Rapid test; WB; Western blot; immunoassay; nucleic acid test.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Algorithms
  • Clinical Laboratory Techniques / methods*
  • False Positive Reactions
  • HIV Infections / diagnosis*
  • HIV-1 / genetics
  • HIV-1 / immunology
  • HIV-1 / isolation & purification*
  • HIV-2 / genetics
  • HIV-2 / immunology
  • HIV-2 / isolation & purification*
  • Humans
  • Immunoassay / methods
  • Nucleic Acid Amplification Techniques / methods
  • Point-of-Care Systems*