Consideration of the Improvement of the Confirmatory Assay for the Anti-HTLV Positive Blood Donation

Youn, Kyoung Won; Kang, Jae Won; Kwon, So Yong; Oh, Deok Ja

Abstract

BACKGROUND
In the Korean Red Cross, anti-HTLV (Human T-cell lymphotropic virus)-1/2 screening assay has been performed in all donated blood except plasmapheresis since April 2009. For anti-HTLV-1/2 positive donors, both Western blot (WB) and nucleic acid amplification test (NAT) are performed as confirmatory assays. In this study, we evalutated the efficiency of the current confirmatory assay scheme to improve the confirmatory assay scheme for anti-HTLV1/2.
METHODS
The results of the HTLV confirmatory assay from April 15th 2009 to April 14th 2015 were analyzed using the Blood Information Management System of the Korean Red Cross. We also investigated the current situation in other countries.
RESULTS
Of 12,923,854 donations, 3,483 (0.027%) showed positive results in anti-HTLV-1/2. Of the 3,483 donations, 499 (14.3%) showed positive results in WB or NAT or both. The number of positive cases in both was 461. Therefore, the concordance rate was 92.4%. In the cases of positive results only in NAT, the WB results were all indeterminate (ID). Most countries are using immunoblot assay as a confirmatory assay for anti-HTLV positive blood donors. In the results, there were no cases of positive result in only NAT with a negative result in immunoblot assay.
CONCLUSION
It was considered that the accomplishment of only WB as a confirmatory assay for anti-HTLV-1/2 positive donors may be sufficient in the aspect of safety and economics. However, in the case of WB ID result, it may be better to perform NAT as a supplemental test.