Comparison of the Murex Hybrid Capture CMV DNA (v2.0) assay and the pp65 CMV antigenemia test for the detection and quantitation of CMV in blood samples from immunocompromised patients.
BACKGROUND
Presently the semiquantitative pp65 cytomegalovirus (CMV) antigenemia test on white blood cells is often used for monitoring transplant patients for the appearance of active CMV infections. However, the need for immediate processing of the specimens and the lack of interlaboratory standardization of the test may sometimes be a disadvantage.


OBJECTIVE
The aim of this study was to investigate the value of the recently developed second version of the Murex Hybrid Capture (MHC) CMV-DNA assay (v 2.0) in comparison with the CMV-pp65 test. The MHC CMV-DNA assay is a quantitative solution hybridization antibody capture assay, using alkaline phosphatase conjugated antibodies and a chemiluminescent substrate.


METHODS
248 EDTA blood samples from 33 renal transplant patients and 32 samples from 22 other immunocompromised patients were tested by both the MHC CMV-DNA assay and the CMV-pp65 test.


RESULTS
The qualitative ( + or -) results of both tests showed an overall concordance of 81.4%. Calculations on the basis of discordancy analyses showed that the sensitivity, the specificity, and the positive and negative predictive values were 87.7, 98.3, 98.6, 85.2% for the MHC CMV-DNA assay and 76.6, 100, 100, 75.5% for the CMV-pp65 test. Comparison of the quantitative results of both tests systems showed a correlation coefficient of 0.837. In addition, retesting of 50 samples with the MHC-CMV-DNA assay showed an excellent reproducibility with a correlation coefficient of 0.992. All patients which were tested regularly (at least five samples) became either positive with both tests or with none of them. Neither test system detected CMV significantly earlier than the other one. Both tests became strongly positive in all transplant patients with symptomatic CMV infections, and both tests showed a rapid decline of CMV during subsequent antiviral treatment.


CONCLUSIONS
The quantitative Murex Hybrid Capture CMV-DNA assay (v 2.0) may become a valuable additional tool in CMV diagnosis. Further studies will be needed to support this preliminary judgement.
Schirm
J
J
Regional Public Health Laboratory, Groningen, The Netherlands. schirmjslg@compuserve.com
Kooistra
A
A
van Son
W J
WJ
van der Bij
W
W
Verschuuren
E
E
Sprenger
H G
HG
Limburg
P C
PC
The
T H
TH
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis / Q000188:drug therapy / Q000821:virology; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000097:blood; D000998:Antiviral Agents / Q000627:therapeutic use; D003587:Cytomegalovirus / Q000276:immunology / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000821:virology; D004279:DNA, Viral / Q000097:blood*; D015774:Ganciclovir / Q000627:therapeutic use; D006801:Humans; D016867:Immunocompromised Host; D016030:Kidney Transplantation / Q000009:adverse effects; D008875:Middle Aged; D010750:Phosphoproteins / Q000097:blood*; D016133:Polymerase Chain Reaction / Q000379:methods; D011933:Reagent Kits, Diagnostic; D014763:Viral Matrix Proteins / Q000097:blood*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D000998:Antiviral Agents; D004279:DNA, Viral; D010750:Phosphoproteins; D011933:Reagent Kits, Diagnostic; D014763:Viral Matrix Proteins; C065418:cytomegalovirus matrix protein 65kDa; D015774:Ganciclovir