Interpretation of low reactivity in the Abbott Architect rHTLV I/II assay

J. H.C. Tosswill, G. P. Taylor*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Objective: The objective of this study is to reduce donor tissue wastage. Aim: The aim of this study is to determine, in the case of the Abbott Architect rHTLV I/II assay, whether a signal/cut-off (S/CO) ratio higher than the manufacturer's recommendation of 1·0 could be applied to diagnose significant HTLV-1 seroreactivity. Background: The detection of human T cell leukaemia virus type 1 (HTLV-1) infection is primarily based on serology often utilising random access platforms. Although current assays have high sensitivity and specificity, in low-prevalence regions, significant numbers of false-positive reactions occur. A comprehensive follow-up is difficult within the time frame of organ donation. This can lead to donor tissue wastage. Methods: A retrospective analysis of 12 250 samples previously tested on the Abbott Architect rHTLV I/II platform and further tested by confirmatory serology/molecular detection to determine the sensitivity and positive predictive value in the S/CO ratio range was conducted. Results: Where the sample S/CO ratio was >20 (n = 498), HTLV infection was confirmed in all but eight subjects. All of these eight had indeterminate confirmatory results, and none were found to be uninfected. Conversely, in the samples within the S/CO ratio range 1–4 (n = 271), no subject was subsequently found to be HTLV-infected although HTLV infection could not be excluded in all cases, primarily due to lack of follow-up samples (n = 60/271). Conclusions: Samples with an S/CO ratio of <4·0 on the Abbott Architect rHTLV I/II platform represent a low risk of HTLV infection in the UK, and organs from such donors might reasonably be considered for transplantation, within the context of appropriate risk–benefit assessment.

Original languageEnglish
Pages (from-to)326-330
Number of pages5
JournalTransfusion Medicine
Issue number4
Publication statusPublished - Aug 2018

Bibliographical note

Funding Information:
We are grateful to the staff in the Virus Reference Department, Public Health England, for laboratory testing and support and to Professor Richard Tedder for critical review and helpful comments on this manuscript. G. P. T. and J. H. C. T. conceived and designed thestudy. J. H.C. T. collatedthe data. J. H.C. T. and G. P. T. analysed the data and coauthored this paper. G. P. T.’s research is supported by NIHR Imperial Biomedical Research Centre.

Publisher Copyright:
© 2017 The Authors. Transfusion Medicine published by John Wiley & Sons Ltd on behalf of British Blood Transfusion Society


  • HTLV-1
  • confirmation
  • screening
  • serology
  • transplantation


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