Abstract: Objective: To study the reliability of flow cytometer UF-100 in detecting asymptomatic urinary tract infections(AUTI) in early pregnancy.Methods: Three-hundred and nine fresh midstream clean-catch urine sample were collected in accordance with standard guideline.10 μl of cleancatch midstream urine specimen was examined by cultures(colony counts of ≥ 10^4~5 CFU/ml) the other portion was tested with UF-100 for presence of bacteria count and white blood cell.Results: Twenty-one patient(6.8%) had cultures of 10,000 or more colony-forming units of a uropathogen per milliliter.The sensitivities of the UF-100 test in identifying patients with positive cultures was 71.4%,and the specificities was 94.1%.Six patients(28.6% 6/21) had negative UF-100 screening tests but positive urine cultures,and other seventeen patients had positive UF-100 screening tests but negative urine cultures,The positive predict value(PPV) of urine UF-100 evaluation was 46.9%.There was a significant difference in positive rate between the two methods(P<0.05),but there was a significant correlation in test results between the two methods(P<0.005).Conclusions: Flow cytometer UF-100 tests are not sufficiently sensitive to be of use in the screening for AUTI and therefore many patients would be missed.Bacteriuria culture must be done in diagnosing AUTI.