Objective: To determine if a clean catch technique can accurately diagnose bacteriuria among incontinent female nursing home residents.
Design: Cultures and dipstick screening test results from paired urine specimens, one collected by a clean catch technique and the other collected by sterile in-and-out catheterization, were compared.
Participants: A total of 101 incontinent female nursing home residents who were being assessed for participation in a larger clinical intervention trial for incontinence.
Measurements: Each urine was tested by a dipstick method for leukocyte esterase and nitrite and sent to a bioclinical laboratory for quantitative culture.
Results: Positive and negative culture results matched in 92 of the 101 paired specimens. Using the catheter specimen as a gold standard, the clean catch had a sensitivity of 90%, specificity of 92%, positive predictive value of 81%, and a negative predictive value of 95%. In a population with symptoms suggestive of infection, among whom the prevalence of bacteriuria would likely be higher than in the asymptomatic residents we studied (e.g., 60% vs 30%), the positive predictive value would increase to 95%, but the negative predictive value would decrease to 86%. The concordance of the results of the urine screening tests was not as good, except for the detection of a positive leukocyte esterase test and a negative nitrite test.
Conclusion: Incontinent female nursing home residents do not necessarily have to be catheterized in order to obtain an accurate quantitative urine culture. Our results using a careful clean catch technique are comparable to those previously reported using urine obtained from a urine-soiled diaper as well as those using a condom catheter technique in men.