Qualitative and semiquantitative polymerase chain reaction testing for cytomegalovirus DNA in serum allows prediction of CMV related disease in livertransplant recipients

Aim-To identify cytomegalovirus (CMV) infection in liver transplant recipie nts by polymerase chain;reaction (PCR) techniques and to separate the cases in which CMV related disease will occur, for whom treatment is indicated, from those in whom infection will remain innocuous. Methods-The combination of qualitative and semiquantitative PCR of serum an d urine was assessed to determine whether these assays can identify those a t risk of CMV related disease and compared their performance with conventio nal approaches to diagnosis. Results-Qualitative PCR of serum had superior specificity, sensitivity, and positive and negative predictive values compared with urine DEAFF (detecti on of early antigen fluorescent foci) and PCR of urine. All episodes of CMV related disease were associated with the presence of CMV DNA by PCR in ser um or urine; CMV was detected before clinical onset in 70% and 60% of cases , respectively. The period over which CMV DNA could be detected was not cor related with CMV related disease. Both peak viral load and cumulative viral load estimated using a semiquantitative PCR method on serum samples positi ve by the qualitative method could be used to distinguish asymptomatic infe ction from CMV related disease with 100% specificity and sensitivity. In co ntrast semiquantitative PCR of urine was of little value. Conclusions-An approach based on PCR testing with a combination of qualitat ive and subsequently semiquantitative serum samples would improve the diagn osis of CMV infection and aid identification of those patients at risk of C MV related disease, allowing treatment to be targeted specifically.