Urinary Dipsticks: Efficacy as Predictor of Urinary Tract Infections

Abstract

Urinalysis and culture are the two most common investigations performed in a microbiology laboratory. Commercial Dipsticks which detect proteins and various enzymes may offer a rapid and inexpensive alternative to urinalysis and culture. An evaluation of the utility of urinary dipsticks (Multistix 10 SG) in predicting urinary tract infections (UTI) was undertaken. A total of 667 urine samples were evaluated from May to August 2012. Sensitivity, specificity, negative and positive predictive values were evaluated. The sensitivity for predicting UTI was low: 62% for leukocyte esterase and nitrite; 67% for leukocyte esterase and proteinuria while it was 74% for leukocyte esterase, nitrite and proteinuria, all three together. However, the negative predictive value (NPV) for UTI was better. NPV for UTI with leukocyte esterase and nitrite was 90.3%; for leukocyte esterase and proteinuria was 90.6% while it was 91.5 % for leukocyte esterase, nitrite and proteinuria together. The positive predictive value was very low. Urinary dipsticks therefore appear to be better tools for excluding UTIs and not for diagnosing UTI.

Evaluation of Urine Dipstick For Leukocyte Esterase Test For Diagnosis of Urinary Tract Infection

“…Urinary biochemical parameters can be evaluated using the urine dipstick screening test. Although the value of urine dipstick has been questioned, it is an inexpensive and rapid diagnostic alternative, [10,11,12,13]. The dipstick test detects urinary parameters such as glucose, protein, nitrite and leukocyte esterase (LE).…”