ARCHITECT rHTLV-I/II immunoassay for blood screening and diagnosis

Background

Detection of HTLV infection continues to be important to control spread of human retroviruses and to protect safety of blood supply. The ARCHITECT rHTLV-I/II assay is a chemiluminescence-based immunoassay, which utilizes HTLV-I, and HTLV-II recombinant antigens and peptides in a double-antigen-sandwich assay format on the Abbott ARCHITECT automated platform. Precision, sensitivity and specificity of the ARCHITECT rHTLV-I/II assay is being presented.

Methods

Assay performance was evaluated on confirmed HTLV-I/II positive specimens and specimens from German Blood Donors and hospitalized patients. External performance evaluation was conducted at two different sites in Portugal. Murex HTLV-I/II EIA was used as comparator assay and INNO-LIA or MP diagnostics HTLV Blot were used for confirmation.

Results

The ARCHITECT rHTLV-I/II assay detected all HTLV-I and HTLV-II specimens (N=406) in accordance to the Murex assay. Analytical sensitivity was equivalent to Murex based on end-point-dilutions. Specificity on HTLV-I/II blood donors was 99.95% (N=5646; 95% CI 99.84-99.99%), SD to cut-off was 15.6. Specificity on a diagnostic population was 99.86% (N= 692; CI 95% 99.20-100%). Precision for samples (1-6 S/CO) was 3.98-4.31%. Presented data support selected cut-off multiplier-value of 0.25 for the ARCHITECT rHTLV-I/II assay. Results from the Receiver-Operating-Curve showed a 99.98% area under the curve which is indicative of high separation power between negative and positive populations.

Conclusions

This study demonstrated excellent sensitivity and specificity of the ARCHITECT rHTLV-I/II assay. The assay is suitable for both blood screening and diagnosis of HTLV infections and therefore reduces risk of transfusion transmitted HTLV and improves safety of blood supply.