DETECTION OF CYTOMEGALOVIRUS IN BLOOD-DONORS BY PCR USING THE DIGENE SHARP SIGNAL SYSTEM ASSAY - EFFECTS OF SAMPLE PREPARATION AND DETECTION METHODOLOGY

Cytomegalovirus (CMV) is an important cause of transfusion-associated morbidity and mortality; however, only 0.4 to 12% of the blood product s obtained from seropositive blood donors transmit infection. The effe cts of three commercially available whole blood sample preparation kit s on the detection of CMV PCR products by a semiquantitative adaptatio n of the Digene SHARP Signal System Assay (DSSSA) in samples from volu nteer blood donors was assessed. Of 101 samples from seropositive bloo d donors, CMV was detected in 0 (0%) of the samples extracted with a Q IAamp blood kit (QIAGEN), 1 (1%) of the samples extracted with an Ampl icor whole-blood specimen preparation kit (Roche), and 8 (8%) of the s amples extracted,vith an Isoquick nucleic acid extraction kit (modifie d by the addition of carrier tRNA) (Microprobe), CMV DNA was not detec ted in samples from seronegative blood donors (n = 13), Nested PCR of selected samples confirmed the detection of CMV in the sane eight samp les extracted with the modified Isoquick nucleic acid extraction kit a nd detected an additional nine CMV-positive samples (n = 50), Samples from volunteer blood donors contain low copy numbers of CMV DNA, PCR a mplification of such specimens can result in analytical Sampling error s, giving results similar to the variations in titers recognized durin g determinations of the 50% tissue culture infective dose. The detecti on of CMV in blood samples from volunteer blood donors by PCR is a fun ction of sample preparation, amplification conditions, and detection m ethodology. Accurate assessments of the clinical utility of CMV DNA de tection by nucleic acid amplification for blood product screening and patients will require highly standardized and quantitative methodology .