The CMV antigenemia assay has been used in recent years as a means of guiding the preemptive therapy of CMV disease in SOT. More recently, concerns have been raised regarding the utility of the test to accurately and precisely detect the virus early enough to reduce morbidity and mortality caused by CMV in transplant recipients.
The primary objective of our study was to determine the performance characteristics of our current method of antigenemia testing in our SOT population.
A large Canadian teaching hospital.
We retrospectively reviewed the charts of all SOT recipients between January 1, 1999 and June 31, 2000 for the 6 months following transplantation. Physical exam, laboratory and treatment information was collected throughout the follow-up period.
Main Outcome Measures
Sensitivity, specificity and predictive values for CMV antigenemia tests.
Of 155 transplant recipients, 21 met our pre-specified exclusion criteria, leaving us with a sample size of 134 patients receiving kidney, liver, lung and kidney-pancreas transplants. The overall performance of our antigenemia assay were as follow; sensitivity 64%, specificity 81%, positive predictive value 76%, negative predictive value 71%. Performance characteristics were also assessed, taking into account baseline recipient and donor serology and test breakpoints used to determine a positive test result. A mean of 18 days passed between onset of signs and symptoms of CMV disease/syndrome and the first recorded positive test result and only 26% of patients had a positive test result before the onset of symptoms. It was found that an antigenemia test result of ³ 1 cell resulted in the most sensitive and specific results, with an increased odds ratio of developing CMV disease.
Our current method of antigenemia testing to guide preemptive ganciclovir therapy in SOT patients is not optimal in terms of performance characteristics or for detecting disease early. More study is needed on new molecular testing to determine if our ability to predict CMV disease can be improved.