Abstract:
Background. The balance between the choices of UTI diagnostic tools in most primary care settings has been settled for by the
more rapid, less labour-intensive dipstick. This study aimed to evaluate the effectiveness of dipstick for diagnosing UTI. Method. A
total of 429 urine samples were collected from patients suspected of UTI; cultured on cysteine-lactose-electrolyte-deficient
(CLED) agar, blood agar, and MacConkey agar; and incubated at 37°C overnight. Urine cultures with bacteria count ≥105 cfu/ml
were classified as “positive” for UTI. A dipstick was used to screen for the production of nitrite (NIT) and leucocyte esterase (LE),
following the manufacturer’s instructions. Biochemical reactions of nitrite and leucocyte esterase > “trace” were classified as
“positive.” A quantitative urine culture was used as the gold standard. Results. The highest sensitivity value and negative predictive
value were recorded for the combined “NIT+ or LE+” dipstick results. The highest specificity value, positive predictive value,
positive likelihood ratio, and negative likelihood ratio were recorded for “nitrite-positive and leucocyte esterase-positive” results.
Combined “nitrite-positive or leucocyte-positive” result was relatively the best indicator for accurate dipstick diagnosis, with
AUC = 0.7242. Cohen’s kappa values between dipstick diagnosis and quantitative culture were <0.6. Conclusion. Combined
performance of nitrite and leucocyte esterase results appeared better than the solo performance of nitrite and leucocyte esterase.
However, little confidence should be placed on dipstick diagnosis; hence, request for quantity culture should be encouraged in the
primary healthcare settings.
