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Discordant human T‐lymphotropic virus screening with Western blot confirmation: evaluation of the dual‐test algorithm for US blood donations
Author(s) -
Stramer Susan L.,
Townsend Rebecca L.,
Foster Gregory A.,
Johnson Ramona,
Weixlmann Barbara,
Dodd Roger Y.
Publication year - 2018
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.14471
Subject(s) - immunoassay , human t lymphotropic virus , medicine , virology , blood donor , chemiluminescent immunoassay , chemiluminescence , screening test , blood donations , virus , antibody , immunology , chemistry , chromatography , family medicine , myelopathy , psychiatry , spinal cord
BACKGROUND Human T‐lymphotropic virus (HTLV) blood donation screening has used a dual‐testing algorithm beginning with either a chemiluminescent immunoassay or enzyme‐linked immunosorbent screening assay (ELISA). Before the availability of a licensed HTLV supplemental assay, repeat‐reactive (RR) samples on a first assay (Assay 1) were retested with a second screening assay (Assay 2). Donors with RR results by Assay 2 were deferred from blood donation and further tested using an unlicensed supplemental test to confirm reactivity while nonreactive (NR) donors remained eligible for donation until RR on a subsequent donation. This “dual‐test” algorithm was replaced in May 2016 with the requirement that all RRs by Assay 1 be further tested by a licensed HTLV supplemental test (Western blot [WB]). In this study, we have requalified the dual‐test algorithm using the available licensed HTLV WB. STUDY DESIGN AND METHODS We tested 100 randomly selected HTLV RRs on screening Assay 1 (Abbott PRISM chemiluminescent immunoassay) but NR on screening Assay 2 (Avioq ELISA) by a Food and Drug Administration–licensed WB (MP Biomedicals) to ensure that no confirmed positives were among those that were RR by Assay 1 but NR by Assay 2. RESULTS Of the 100 samples evaluated, 79 of 100 were WB seronegative, 21 of 100 indeterminate, and 0 of 100 seropositive. Of the 79 of 100 seronegative specimens, 73 of 79 did not express any bands on WB. CONCLUSIONS We demonstrated that none of the 100 samples RR on Assay 1 but NR on Assay 2 were confirmed positive. This algorithm prevents such donors from requiring further testing and from being deferred.