Diagnosis of HIV-1 infection: Performance of Xpert Qual and Geenius supplemental assays in fourth generation ELISA-reactive samples

Aviya Rakovsky, Yael Gozlan, Ravit Bassal, Marina Wax, Rachel Shirazi, Mary Bakhanashvili, Zipi Kra-Oz, Sara Radian-Sade, Haim Ben-Zvi, Licita Schreiber, Dana G. Wolf, Yonat Shemer-Avni, Daniel Chemtob, Ella Mendelson, Orna Mor

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Background: Architect (AR) and Vidas (VD) fourth generation HIV screening immunoassays, which identify early stages of HIV infections, could have false positive results especially at low signal/cutoff (S/C) AR values. Geenius HIV1/2 (GS) is a specific confirmation line immunoassay that is not highly sensitive to early HIV infections. An HIV-1 RNA assay may better detect such infections. Objectives: To evaluate all AR-VD reactive samples with GS results, and to assess Xpert Qual HIV-1 RNA assay (XQ) as an alternative to GS, in the first low S/C AR-VD-reactive samples from a tested individual. Study design: First AR-VD-reactive-GS-tested results from all individuals with resolved HIV status, collected between March 2015 and March 2017 (n = 749), were retrospectively assessed. Samples with AR-VD-reactive-GS-discordant results and those with low S/C AR-VD-reactive results, were tested by XQ. Receiver operating characteristic (ROC) analysis of GS and XQ sensitivity/specificity was performed. Results: Overall, 94.1% (705/749) of AR-VD-reactive results were true HIV-1 positive. All samples with <3 S/C AR values were false positive. XQ resolved all first samples with AR-VD-reactive-GS-discordant results. The diagnostic accuracy of XQ in low (≤33 S/C) AR-VD-reactive samples was better than that of GS (97.6%, 81/83 versus 73.5%, 61/83, p < 0.01). ROC analysis for low S/C AR samples was optimal for pooled XQ and GS results. Conclusions: Incorporating XQ in the current screening algorithm for the first AR-VD-reactive-GS-discordant samples may significantly reduce overall turn-around time of HIV-1 diagnosis.

Original languageEnglish
Pages (from-to)7-10
Number of pages4
JournalJournal of Clinical Virology
StatePublished - Apr 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 Elsevier B.V.


  • Architect
  • Geenius
  • HIV-1 infection
  • Vidas
  • Xpert HIV-1 Qual


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