Validity of urine dipstick test to assess eradication of urinary tract infection in persons with spinal cord injury.

OBJECTIVES: To prospectively study the predictive value (PV) of urine nitrite (NIT) dipstick testing against urine cultures during antibiotic treatment for urinary tract infection (UTI), and other situations, in patients with spinal cord injury (SCI).

METHODS: Inpatients with SCI on intermittent catheterisation (IC) or a Foley indwelling catheter (FC) were included. Urine specimens were collected in patients without symptoms (routine), with symptoms of UTI (suspicion), and on day 4 of a 5-day antibiotic treatment (ATB+3).

RESULTS: A total of 157 urine samples were collected in 61 patients: 34 were on IC (95 samples) and 27 on FC (62 samples). The prevalence of asymptomatic bacteriuria in the urine cultures was 89% in routine (70 samples). At ATB+3, microbiological cure was found in 27/30 specimens (IC group) and 2/6 (FC group). In the routine condition, the specificity and positive PV of the NIT tests was 1.00 and sensitivity 0.63. The negative PV was low in both groups. In suspicion of UTI, the sensitivity was between 0.69 and 0.55, the positive PV was 1.00 and the negative PV 0.00 for both groups. At ATB+3, the negative PV and sensitivity was 1.00, specificity 0.85 and positive PV 0.43 in the IC group, and in the FC group, specificity was 1.00, negative PV 0.33 and sensitivity 0.00.

CONCLUSION: In the SCI population on intermittent or indwelling catheters with high prevalence of bacteriuria, dipstick testing helped assess the eradication of germs during antibiotic treatment, but showed no value in the decision making process for UTI.

LEVEL OF EVIDENCE: 3.