Comparison Between Qualitative Polymerase Chain Reaction and pp65 Antigenemia for the Diagnosis of Cytomegalovirus Infection in Immunosuppressed Patients

Abstract

Introduction: Cytomegalovirus (CMV) infection is frequent and has significant morbidity and mortality in immunosuppressed individuals, especially in transplanted and HIV-positive patients with advanced disease. Objective: This study compared the performance of qualitative polymerase chain reaction (PCR) and pp65 antigenemia methods for the diagnosis of CMV infection in immunosuppressed patients. Methods: A total of 216 of peripheral blood samples were collected from 85 inpatients or outpatients, from August 2006 through January 2007 from Hospital de Clínicas de Porto Alegre (HCPA). Results: Of the 216 samples, 35 had positive results and 181 were negative with regard to one and/or another technique. Of the 35 positive samples, 16 were positive in both techniques; 12 were positive for PCR and negative for antigenemia, and seven samples were positive for antigenemia but negative for PCR. Considering antigenemia as the gold standard, the PCR technique showed sensitivity of 69.6%, specificity of 93.8%, positive predictive value of 57.1%, and negative predictive value of 96.3%. The kappa correlation coefficient was 0.578. Discussion: These results demonstrate that the qualitative PCR has moderate sensitivity and high specificity for the diagnosis of CMV infection. Despite its limitations, it can be used for diagnosis exclusion in patients under CMV infection suspicion because of its simplicity, low cost and of easy execution.