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Interlaboratory Comparison of Epstein‐Barr Virus Viral Load Assays
Author(s) -
Preiksaitis J. K.,
Pang X. L.,
Fox J. D.,
Fenton J. M.,
Caliendo A. M.,
Miller G. G.
Publication year - 2009
Publication title -
american journal of transplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 188
eISSN - 1600-6143
pISSN - 1600-6135
DOI - 10.1111/j.1600-6143.2008.02514.x
Subject(s) - coefficient of variation , replicate , viral load , medicine , virus , virology , chromatography , statistics , chemistry , mathematics
To assess interlaboratory variability in qualitative and quantitative Epstein‐Barr virus (EBV) viral load (VL) testing, we distributed a panel of samples to 28 laboratories in the USA, Canada and Europe who performed testing using commercially available reagents (n = 12) or laboratory‐developed assays (n = 18). The panel included two negatives, seven constructed samples using Namalwa and Molt‐3 cell lines diluted in plasma (1.30–5.30 log 10 copies/mL) and three clinical plasma samples. Significant interlaboratory variation was observed for both actual (range 1.30–4.30 log 10 copies/mL) and self‐reported (range, 1.70–3.30 log 10 copies/mL) lower limits of detection. The variation observed in reported results on individual samples ranged from 2.28 log 10 (minimum) to 4.14 log 10 (maximum). Variation was independent of dynamic range and use of commercial versus laboratory‐developed assays. Overall, only 47.0% of all results fell within acceptable standards of variation: defined as the expected result ± 0.50 log 10 . Interlaboratory variability on replicate samples was significantly greater than intralaboratory variability (p < 0.0001). Kinetics of change in VL appears more relevant than absolute values and clinicians should understand the uncertainty associated with absolute VL values at their institutions. The creation of an international reference standard for EBV VL assay calibration would be an initial important step in quality improvement of this laboratory tool.