Sensitivity of individual‐donation and minipool nucleic acid amplification test options in detecting window period and occult hepatitis B virus infections

Abstract

BACKGROUND Several comparison studies showed that the Ultrio assay (Novartis Diagnostics) used in individual-donation nucleic acid amplification testing (ID-NAT) format was as sensitive as the TaqScreen assay (Roche) on minipools of six donations (MP6), but the sensitivity of HBV DNA detection has been improved in the new Ultrio Plus version of the assay. A head-to-head comparison study was designed to compare the clinical sensitivity of the Ultrio and Ultrio Plus assay in ID, MP4, and MP8 formats using TaqScreen MP6 as a reference assay. STUDY DESIGN AND METHODS Plasma samples of 107 hepatitis B surface antigen (HBsAg)-negative, HBV ID-NAT (Ultrio) positive-yield samples and 29 HBV DNA–negative, HBsAg-positive samples were used for comparison of NAT options in replicate testing of dilutions. Viral loads and relative sensitivities were determined by probit analysis against the Eurohep standard. RESULTS Ultrio Plus detected a significantly (p < 0.00001) higher proportion of replicate assays on HBV NAT yields (77%) than Ultrio ID (62%) and TaqScreen MP6 (47%), whereas Ultrio Plus MP4 and MP8 detected 53 and 41%, respectively. On HBsAg-yield samples missed by Ultrio screening, the reactivity rate increased significantly (p < 0.0001) from 23% in Ultrio to 65% in Ultrio Plus and further to 72% (p = 0.10) in the TaqScreen assay. The overall improvement factor of the analytical sensitivity offered by the target enhancer reagent in the Ultrio Plus assay was 2.5 (2.0–3.1)-fold on the Ultrio yield samples, but 43 (11–350)-fold on the HBsAg yields. In ID-NAT format the analytical sensitivity of TaqScreen relative to Ultrio Plus was 2.0 (1.0–4.2), 0.9 (0.7–1.3), and 1.6 (0.9–3.0) on the Eurohep standard, HBV NAT–, and HBsAg-yield samples respectively. CONCLUSION The clinical sensitivity of the currently available commercial NAT methods is mainly driven by the pool size.

The yield of universal antibody to hepatitis B core antigen donor screening in theNetherlands, a hepatitis B virus low‐endemic country

“…The (estimated) prevalence of OBI in donor populations of low‐endemic countries strongly depends on the LOD of HBV NAT screening and varies between 0.1% and 3.7% . Recent studies from Switzerland and South Africa using ID‐NAT emphasize that the majority of donors with OBI (75 and 61%, respectively) have viral loads below 20 IU/mL and would slip through HBV NAT MP6 screening . Since virtually all donors with OBI have detectable anti‐HBc, the residual risk associated with OBI below the limit of HBV NAT detection will be eliminated by universal anti‐HBc screening .…”

“…Although universal anti‐HBc screening has increased the safety of the Dutch blood supply, its exact yield cannot be determined. First, ID‐NAT was not performed for anti‐HBc–reactive donors at first‐time anti‐HBc screening, preventing accurate diagnosis of OBI . Second, true resolved HBV infection and OBI cannot be distinguished due to the complexity of confirming anti‐HBc reactivity and OBI.…”

Occult Hepatitis Infection in Transfusion Medicine: Screening Policy and Assessment of Current Use of Anti-HBc Testing

“…Currently, the efficiency of each NAT system is closely related to the size of the pool [65]. Many countries have chosen to reduce the number of samples/pool by using mini pool (MP) testing, thus increasing the analytical sensitivity [66].…”

Evaluation of an individual‐donation nucleic acid amplification testing algorithm for detecting hepatitis B virus infection in Chinese blood donors

“…In this article we describe the HBV DNA screening data in 1,205,796 HBsAg and antibody to HCV and HIV ELISA‐negative donations that were tested individually by the Ultrio assay. The analytical performance characteristics and clinical evaluation data of this multiplex method have been described in several articles . In the ID‐NAT algorithm prescribed by the manufacturer initial Ultrio‐reactive donations are tested in the discriminatory (d)HBV, HCV, and HIV assays and those not detected by any of the discriminatory tests are supposed not to be used for transfusion.…”