Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2016

In this evaluation we compare an existing commercial assay (Roche EBV: MagNAPure LC/LightCycler 1.0) with Abbott RealTime EBV assay (EBV-RT) for the quantitation of EBV in plasma samples. Serial dilutions of an Acrometrix EBV DNA standard (1.00x10⁴ IU/mL) demonstrated a consistent lower limit of detection of <40 IU/mL for EBV-RT. Comparisons over four consecutive EBV-RT runs using the same control demonstrated an inter-assay precision of ±0.09 log₁₀ (CV= 21%). Serial dilutions of human plasma samples of known viral load demonstrated a consistent lower limit of detection of <1.00x10³ copies/mL in the Roche EBV Assay (R-EBV). The R-EBV demonstrated an inter-assay precision over four consecutive runs of ±0.26 log₁₀ (CV=69%) using an in-house EBV plasmid positive control (5.00x10⁵ copies/mL). An assessment of reproducibility was performed using five replicates of a single patient sample (R-EBV 6.00x10³ copies/mL) on both assays. The EBV-RT demonstrated an intra-assay precision of ±0.07 log₁₀ (CV=16%) and the R-EBV demonstrated an intra-assay precision of ±0.16 log₁₀ (CV=36%). Thirty-seven plasma samples were prospectively tested in a blinded fashion with both assays. The R-EBV reports copies/ml with no IU/mL conversion reported in the literature. The EBV-RT assay reports results to the IU/mL standard. For this reason we determined an approximate copies/mL (Roche) conversion to IU/mL using a number of patient samples across a range of viral loads. Of the 27 samples reported as <1.00x10³ copies/mL (R-EBV), 23 were reported as EBV not detected (EBV-RT), with two samples reporting an absolute viral load of 1.50x10¹ IU/mL and 3.10 x10¹ IU/mL respectively and one sample reported Detected <40 IU/mL. An evaluation of workflow was performed with EBV-RT showing a shorter turn-around-time of 7.75 hours compared to 13.4 hours per 96 tests. In addition, higher throughput was achieved with 93 samples per run verses 24 samples per run. Other advantages included primary barcode reading, full process controls, LIS interfacing and traceability of on board consumables. Overall EBV-RT out-performed the R-EBV assay.