THE LABORATORY DIAGNOSIS OF CYTOMEGALOVIRUS INFECTIONS

Rapid and accurate diagnosis of cytomegalovirus (CMV) infection is imp erative with the advent of effective antiviral therapy (gangiclovir, f oscarnet, CMV hyperimmune globin). Applications of conventional call c ulture (CC), shell vial assay (SV), serological testing, antigenemia a ssay (AG) as well as molecular methods [polymerase chain reaction (PCR ), branch DNA (b-DNA) and hybrid capture (HC)] to various patient popu lations and specimen types are discussed. A three year study of 670 sp ecimens [354 urines, 205 peripheral blood leukocytes (PBLs), 56 upper respiratory and 55 tissues] compared CMV CC and SV isolation rates. Of the total, 124 (18.5%) were positive by either or both techniques. Fo r each specimen type the number of positives detected by SV was greate r than CC (urine 28 vs 15, PBLs, 12 vs 2). However, of 124 positives, 21 were solely CC positive. A comparison of SV to AG in 230 PBLs yield ed a sensitivity of 100% and specificity of 68.3%. The low specificity when compared to SV may be due to the increased sensitivity of AG. Fi fty-nine PBLs were examined for differing immunostaining techniques [I mmunoperoxidase (IF) vs Immunofluorescence (IF)]. IF stained PBLs show ed an increased number of positive cells per preparation and greater s tain intensity for ease of interpretation.