Effect of leukocyte concentration and inoculum volume on the laboratory identification of cytomegalovirus in peripheral blood by the centrifugation culture-antigen detection methodology.
OBJECTIVE
To investigate the rate of Cytomegalovirus (CMV) detection in peripheral blood by shell vial assay-indirect immunofluorescent assay technology using two leukocyte inocula concentrations and different inoculum volumes containing equivalent cell concentrations.


METHODS
Leukocyte inocula concentrations of 2 x 10(5) and 4 x 10(5) cells per 0.2 mL were assayed for the presence of CMV by shell vial assay-indirect immunofluorescent assay. The effect of different inoculum volumes (0.2 and 0.4 mL) containing an equivalent cell concentration of 4 x 10(5) was evaluated as well. The data were compared to conventional MRC-5 tube cultures, including blind passage.


METHODS
Ninety-five patients (101 specimens) were tested sequentially. The test population consisted primarily of patients suffering from the acquired immunodeficiency syndrome.


METHODS
The diagnostic virology laboratory, acquired immunodeficiency syndrome clinics, and hospital wards.


RESULTS
Among the 101 specimens tested by shell vial assay-indirect immunofluorescent assay, the rate of CMV sensitivity increased by 36% using the higher leukocyte inoculum concentration of 4 x 10(5) cells per 0.2 mL (P = .002; Cochran's Q test). No significant difference in CMV yield was identified using equivalent cell concentrations with inocula volumes of 0.2 or 0.4 mL. The CMV sensitivity rate using the higher leukocyte inoculum surpassed that obtained by conventional tube culture-blind passage.


CONCLUSIONS
These data denote the importance of leukocyte concentration on the rate of CMV detection in peripheral blood by the shell vial assay-indirect immunofluorescent assay. The data also point out the need to establish a standardized blood preparation protocol to achieve optimal clinical relevance of this widely used laboratory test.
Lipson
S M
SM
Jane and Dayton Brown and Dayton T. Brown, Jr., Virology Laboratory, Department of Medicine, North Shore University Hospital-Cornell University Medical College, Manhasset, NY 11030, USA.
Falk
L H
LH
Lee
S H
SH
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis*; D000956:Antigens, Viral / Q000032:analysis*; D002478:Cells, Cultured; D002498:Centrifugation; D003587:Cytomegalovirus / Q000276:immunology / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000175:diagnosis*; D005188:False Negative Reactions; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007958:Leukocyte Count; D009504:Neutrophils / Q000821:virology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014766:Viremia / Q000175:diagnosis*
D000956:Antigens, Viral