Screening for asymptomatic bacteriuria in pregnancy: urinalysis vs urine culture.
BACKGROUND
Asymptomatic bacteriuria is common during pregnancy. Its average prevalence is 6%. It is an important risk factor for acute pyelonephritis, hypertension, preeclampsia, fetal wastage, low birthweight, and prematurity. This study was performed to determine the usefulness of urine microscopy as a substitute for doing a screening urine culture.


METHODS
The medical records of all first trimester obstetric visits from 1984 to 1990 were reviewed at a major university. The results of 888 screening urinalyses were recorded and compared with those of subsequent urine cultures.


RESULTS
Fifty-four cultures had growth of a single organism with a bacteria level of at least 1000 organisms per milliliter. In the prediction of a positive culture, the microscopic findings of five or more leukocytes per high-power field (HPF) showed a sensitivity of 94.4% and a specificity of 95.0%.


CONCLUSIONS
Physicians should test the urine of all prenatal patients at their first visit and send to the laboratory only those specimens with 5 or more leukocytes per HPF. Using this method, unnecessary screening urine cultures will be substantially reduced.
Department of Family Medicine, American University of Beirut.
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Abyad
D000293:Adolescent; D000328:Adult; D001437:Bacteriuria / Q000175:diagnosis*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis*; D011261:Pregnancy Trimester, First; D012680:Sensitivity and Specificity; D016482:Urinalysis / Q000592:standards; D014556:Urine / Q000382:microbiology