BACKGROUND: Cytomegalovirus (CMV) remains a major cause of morbidity and mortality for liver transplant recipients. Although the CMV pp65 antigenemia (AG) assay has been widely used to monitor patients for CMV infection after liver transplantation, real-time PCR is becoming the standard procedure. The World Health Organization (WHO) International Reference Standard for CMV quantification has become available to standardize values diagnostic of CMV infection.

MATERIAL AND METHODS: Our in-house real-time PCR assay was standardized using the WHO standard reagents. Levels of CMV DNA in 1339 blood samples obtained from 190 liver transplant recipients were quantified and expressed in international units, and results were then compared with those of the CMV pp65 AG assay performed on the same blood samples. Correlation was assessed and receiver operating characteristic curves were analyzed to determine the optimal cut-off value for CMV DNA (IU/mL) PCR results.

RESULTS: Significant correlation was found between results of the 2 assay methods (p<0.001, r=0.715); a PCR result of ≥288 IU/mL predicted a positive result by the CMV AG assay (1 positive cells/150 000 leukocytes) with a sensitivity of 67.4% and specificity of 94.8%.

CONCLUSIONS: To the best of our knowledge, this is the first report to compare CMV AG and real-time PCR (calibrated to the WHO standard) results in a large number of recipients after liver transplantation. Use of this technique may provide useful information for the management of CMV infection.

Keywords: Liver Transplantation, Real-Time Polymerase Chain Reaction, Reference Standards