Urine Dipstick Testing and Urinalysis
Urine Dipstick testing is an inexpensive way to quickly ascertain the urine components such as glucose, ketones, specific gravity, P.H., leukocytes, nitrites, protein, bilirubin, and blood. Siemens is a company that makes several different types of stripes based upon what is tested on the strip. For UTI testing, any strip that measures leukocytes and nitrites is sufficient. The other analytes are not necessary for the diagnosis of an uncomplicated UTI. This system’s major drawback is that it relies on color, and color interpretation varies amongst users. The error rate of samples using color visualization alone is 12.4% with Siemens 10 S.G. strips. One study showed that in 93% of cases, a negative strip for leukocyte and nitrite was confirmed negative by urine culture. Therefore, dipstick testing is a practical rule-out tool for suspected UTI testing. To test a patient’s urine, collect a sample of urine in a sterile container. Dip a reagent paper into the sample and hold it in place for a few seconds. Remove the strip and knock off any extra urine drops. The paper will turn different colors based upon the contents of the urine. Compare the patient’s sample to the reference sample.
Urinalysis (U.A.) is an inexpensive, effective way to diagnosis a UTI. A UA informs of leukocyte esterase, nitrites, P.H., protein, blood, glucose, ketones, urobilinogen, and glucose. Nitrates are not always converted to nitrites by urinary bacteria and have only a 54% specificity for UTI.
A microscopic exam verifies the presence of white blood cells (WBCs), red blood cells (RBCs), epithelial cells, bacteria, and yeast. The presence of WBCs and bacteria are highly specific signs of a UTI. A negative UA is a good predictor of a negative culture; however, a positive U.A. does not correlate well with positive cultures. Cultures are not recommended for acute uncomplicated urinary tract infections, and if a culture is required, refer the patient to a provider.14 Requirements for lab testing to exercise prescriptive authority varies by state, and we recommend checking with your state board of pharmacy.