Open AccessComparison of a Duplex Quantitative Real-Time PCR Assay and the COBAS Amplicor CMV Monitor Test for Detection of Cytomegalovirus
Author(s) -
Björn Herrmann,
Viviana Cavaglia Larsson,
Carl-Johan Rubin,
Fredrik Sund,
BrittMarie Eriksson,
Johan Arvidson,
Zhibing Yun,
Kåre Bondeson,
Jonas Blomberg
Publication year - 2004
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.42.5.1909-1914.2004
Subject(s) - real time polymerase chain reaction , duplex (building) , virology , microbiology and biotechnology , detection limit , biology , primer (cosmetics) , polymerase chain reaction , gene , chemistry , dna , chromatography , genetics , organic chemistry
A duplex quantitative real-time PCR (qPCR) assay was designed to detect both the polymerase gene (pol) and the glycoprotein gene (gB) of cytomegalovirus (CMV). The detection limit of the qPCR was determined to be 1 to 3 copies/reaction and the linear measure interval was 10(3) to 10(8) copies/ml. The qPCR system was compared to the COBAS Amplicor CMV Monitor test (COBAS) by an analysis of 138 plasma samples. Both systems detected CMV in 71 cases and had negative results for 33 samples. In addition, 34 samples were positive by qPCR and negative by the COBAS assay, but in no case was the COBAS result positive and the qPCR result negative. Thus, qPCR detected 48% more positive cases than the COBAS method. For samples with > or = 10(5) copies/ml by qPCR, a saturation effect was seen in the COBAS assay and quantification required dilution. Copy numbers for pol and gB by qPCR generally agreed. However, the reproducibility of qPCR assays and the need for an international standard are discussed. Discrepant copy numbers for pol and gB by qPCR were found for samples from two patients, and sequence analysis revealed that the corresponding CMV strains were mismatched at four nucleotide positions compared with the gB fragment primer sequences. In conclusion, a duplex qPCR assay in a real-time format facilitates quantitative measurements and minimizes the risk of false-negative results.