[Monitoring techniques in cytomegalovirus infection in solid organ transplant recipients].

The availability of antiviral drugs for cytomegalovirus (CMV) in clinical practice, along with advances in methods of laboratory diagnosis, has substantially alleviated the negative effects of CMV infection in solid organ transplant recipients. Nevertheless, CMV continues to be a significant cause of morbidity and mortality in these patients. Virological monitoring plays a crucial role in controlling these negative consequences. Several diagnostic techniques are now available but not all are applicable in the transplant setting, nor are they all suitable for different clinical situations. Selection of a particular method depends on the clinical objective, the technical profile of the test and the possibilities of the laboratory. Serological tests are useful during pretransplant evaluation of both donor and candidates, the most suitable for this purpose being those that detect IgG antibodies. After transplantation, methods for determining CMV viral load are the cornerstone of diagnosis, prognosis (e.g., as a guide for preemptive therapy), and antiviral treatment monitoring, as well as a first alert on the emergence of drug resistant mutants. The pp65 antigenemia test remains useful as a measure of CMV viral load, but molecular assays are progressively replacing antigenemia in most laboratories because of technical issues. Despite advances in methodological standardization, no reference breakpoint values for viral load interpretation are available, and each center should obtain these values based on their own experience.