Immunological detection of cytomegalovirus early antigen on monolayers inoculated with urine specimens by centrifugation and cultured for 6 days as alternative to conventional virus isolation.

Detection methods for human cytomegalovirus were evaluated with 431 urine samples from 30 bone marrow and 88 kidney transplant recipients. Low-speed centrifugal inoculation was followed by early antigen (EA) detection by means of indirect immunofluorescence with a monoclonal antibody after 1 (EA-1) and 6 (EA-6) days of cultivation. The results were compared with those of conventional virus isolation (CVI). Of 68 positive samples, 49 (72%) were detected with EA-1, 58 (85%) were detected with EA-6, and 43 (63%) were detected with CVI. The combination of EA-1 and EA-6 showed positive results with 66 samples (97%), which is significantly better than with CVI (P less than 0.001). With the exception of one patient, all CVI-negative but EA-positive samples had either significant rises in immunoglobulin G (IgG) or IgA antibody titer or IgM antibodies present in the sera. These data indicate that the method with EA detection can replace CVI, provided that each sample is inoculated in duplicate. Sample 1 is examined after 1 day, and if it is negative, sample 2 is incubated for a further 5 days, followed by detection of cytomegalovirus.