Evaluation of a new, fully automated immunoassay for detection of HTLV‐I and HTLV‐II antibodies

Screening blood donations for human T‐lymphotropic virus types I and II (HTLV‐I/II) continues to be important in protecting the safety of blood products and controlling the global spread of these retroviruses. We have developed a fully automated, third generation chemiluminescent immunoassay, ARCHITECT rHTLV‐I/II, for detection of antibodies to HTLV‐I/II. The assay utilizes recombinant proteins and synthetic peptides and is configured in a double antigen sandwich assay format. Specificity of the assay was 99.98% (9,254/9,256, 95% CI = 99.92–100%) with the negative specimens from the general population including blood donors, hospital patients and pregnant women from the US, Japan and Nicaragua. The assay demonstrated 100% sensitivity by detecting 498 specimens from individuals infected with HTLV‐I (n = 385) and HTLV‐II (n = 113). ARCHITECT rHTLV‐I/II results were in complete agreement with the Murex HTLV‐I/II reference assay and 99.7% agreement with the Genelabs HTLV Blot 2.4 confirmatory assay. Analytical sensitivity of the assay was equivalent to Murex HTLV‐I/II assay based on end point dilutions. Furthermore, using a panel of 397 specimens from Japan, the ARCHITECT rHTLV‐I/II assay exhibited distinct discrimination between the antibody negative (Delta Value = −7.6) and positive (Delta Value = 7.6) populations. Based on the excellent specificity and sensitivity, the new ARCHITECT rHTLV‐I/II assay should be an effective test for the diagnosis of HTLV‐I/II infection and also for blood donor screening. J. Med. Virol. 80:484–493, 2008. © 2008 Wiley‐Liss, Inc.