Role of Urine Dipstick Test in Diagnosis of UTI in Urolithiasis Patients Attending BPKIHS

Abstract

Background: Urolithiasis and its association with urinary tract infection (UTI) is one of the most common diseases scenario encountered in clinical practice and account for significant morbidity and high medical costs. Though urine culture is gold standard, it is expensive and  time consuming. Therefore, this study was carried out to compare dipstick urinalysis with urine microscopy and urine culture results and identify the common uropathogens and their antimicrobial susceptibility pattern.

Materials and Methods: This was a hospital based study carried out in Microbiology laboratory, BPKIHS,  Dharan, Nepal. Clean catch midstream urine specimen were collected from patients with urolithiasis. Dip stick test (leukocyte esterase and nitrite) and microscopic examination were carried out. The culture isolates were identified and antimicrobial susceptibility test was performed following Clinical and Laboratory Standards Institute (CLSI) guidelines.

Result: Among 88 urine samples recruited, leukocyte esterase (LE) was detected in 35 (39.8%) and nitrite test was positive in 26 (29.5%); pyuria in 56 (63.3%) and 44 (50%) yielded growth in urine. Escherichia coli (46.7%) was the most common bacteria isolated from urine culture. Almost all the uropathogens isolated showed susceptibility to commonly used antibiotics. Considering urine culture as gold standard, sensitivity, specificity, PPV and NPV of LE was 86.6%, 91.75%, 70.5% and 90.9% respectively and  nitrite test was 56.8% sensitive and 97.7% specific with PPV 96.15% and NPV 69.35% respectively.

Conclusion: The study demonstrates that the urine dipstick test seems to be useful to rule out the infection but positive test results have to be confirmed by culture.