The purpose of this study is to assess the validity and reproducibility of the MP Diagnostics HTLV Blot 2.4 in blood specimens testing repeat reactive (RR) on the first FDA licensed screening assay (Abbott Prism) and non-reactive (NR) on the second FDA licensed screening assay (Avioq ELISA).

This is a prospective study designed to assess the safety and effectiveness of a dual algorithm testing for HTLV I/II in blood donors. The study hypothesis is that blood donors testing repeat reactive (RR) on the first FDA licensed HTLV screening assay and non-reactive (NR) on a second FDA licensed screening assay will be confirmed as indeterminate or negative on the MP Diagnostics HTLV Blot 2.4.

Inclusion Criteria:

1. Male or female
2. Completion of a health history evaluation for routine donor screening
3. Provided a routine blood donation
4. Tests repeat reactive by the Abbott PRISM HTLV assay and non-reactive on the AVIOQ Elisa HTLV assay

Exclusion Criteria:

1. Unwilling or unable to provide informed consent to blood donation
2. Inadequate sample volume for testing
3. Unable to provide samples that meet the suitability requirements for testing

All populations are from whole blood donors.

Individual patient data (IPD) was deidentified prior to sharing.