OPTIMIZATION OF DETECTION OF CYTOMEGALOVIRUS VIREMIA IN TRANSPLANTATION RECIPIENTS BY SHELL VIAL ASSAY

Cytomegalovirus (CMV) viremia is a widely used laboratory marker of CM V disease following transplantation and is additionally used to trigge r preemptive antiviral therapy, Despite this, the optimal method for d iagnosing CMV viremia in transplantation recipients remains unknown. T o determine the sampling frequency and blood volume required for the o ptimal diagnosis of viremia by shell vial assay, a prospective study o f 46 viremic transplantation recipients was conducted, Blood specimens (2.5 and 5 ml) were collected twice, 3 h apart, at a median of 1.4 da ys (range, 1 to 3 days) after the triggering shell vial positive blood had been collected. Considering a single 2.5-ml specimen, an average of only 40% of previously viremic patients had documented CMV in their blood; this increased to 50% when a second 2.5-ml sample of blood was collected 3 h later, The yields of two 2.5-ml versus two 5-ml samples were 50 versus 61%, respectively, Viremia as detected by shell vial a ssay is intermittent, and increasing the frequency and volume of blood sampling increases its diagnosis. These results have implications in diagnosis of CMV infection and its preemptive therapy.