Viral load testing across 554 laboratories showed high interlaboratory variability (interquartile ranges up to 1.46 log10 copies/ml), with some improvement when WHO international units were adopted.
Observational (n=554)
Yes
Does calibration to WHO quantitative international standards improve interlaboratory agreement for viral load testing?
Introduction of WHO international quantitative standards for viral load testing may help reduce interlaboratory variability, though significant variability remains a challenge.
ABSTRACT It has been hoped that the recent availability of WHO quantitative standards would improve interlaboratory agreement for viral load testing; however, insufficient data are available to evaluate whether this has been the case. Results from 554 laboratories participating in proficiency testing surveys for quantitative PCR assays of cytomegalovirus (CMV), Epstein-Barr virus (EBV), BK virus (BKV), adenovirus (ADV), and human herpesvirus 6 (HHV6) were evaluated to determine overall result variability and then were stratified by assay manufacturer. The impact of calibration to international units/ml (CMV and EBV) on variability was also determined. Viral loads showed a high degree of interlaboratory variability for all tested viruses, with interquartile ranges as high as 1.46 log 10 copies/ml and the overall range for a given sample up to 5.66 log 10 copies/ml. Some improvement in result variability was seen when international units were adopted. This was particularly the case for EBV viral load results. Variability in viral load results remains a challenge across all viruses tested here; introduction of international quantitative standards may help reduce variability and does so more or less markedly for certain viruses.
Hayden et al. (Thu,) conducted a observational in Viral load testing (n=554). Calibration to WHO quantitative international standards was evaluated on Interlaboratory variability. Viral load testing across 554 laboratories showed high interlaboratory variability (interquartile ranges up to 1.46 log10 copies/ml), with some improvement when WHO international units were adopted.
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