EVALUATION OF THE AMPLICOR CYTOMEGALOVIRUS TEST WITH SPECIMENS FROM HUMAN IMMUNODEFICIENCY VIRUS-INFECTED SUBJECTS

The AMPLICOR cytomegalovirus (CMV) test, a new qualitative assay for t he detection of CMV DNA in plasma, was compared to conventional method s and quantitative PCR (Q-PCR) assays by using leukocytes and plasma f rom 179 blood samples from subjects with AIDS. For the diagnosis of CM V disease, cell-based assays such as a Q-PCR with polymorphonuclear le ukocytes (Q-PCR-PMNL) and a pp65 antigenemia assay had the highest sen sitivities but suffered from a lack of specificity. The best agreement between the results of the Q-PCR-PMNL assay and those of the AMPLICOR test was found when a threshold diagnostic value of 690 copies per 10 (5) cells was selected for the Q-PCR-PMNL assay. In that context, the AMPLICOR CMV test had a sensitivity of 96.4% and a specificity of 95.3 % when results were compared to results of the cell-based PCR assay. T his threshold was close to the one described as associated with the be st sensitivity and specificity for the diagnosis of CMV disease in a r ecently published study (4), Blood samples that tested positive by the Q-PCR PMNL assay but negative by the AMPLICOR CMV test were associate d with viral loads (mean, 785 copies, median, 96 copies per 10(5) leuk ocytes) lower than the viral loads of blood samples that tested positi ve by both assays (mean, 21,452 copies; median, 9,784 copies per 10(5) leukocytes) (P = 0.003), The AMPLICOR CMV test gave positive results at least 48 days before the development of symptomatic CMV disease in a longitudinal analysis of a limited subset of patients (n = 6) from w hom sequential specimens were available for testing. In conclusion, th e AMPLICOR CMV test is a very convenient assay combining rapidity, sim plicity, and the possibility of batch testing. ii positive result by t his test seems particularly important since this implies, in most inst ances, the presence or the imminence of CMV disease, although a negati ve test result does not rule out disease.