Cost-effective screening by nursing staff for urinary tract infection in the spinal cord injured patient

Screening tests for urinary tract infections (UTI) are used in the clinical laboratory setting. This study evaluated the efficacy of screening by nursing staff on the inpatient unit, instead of the clinical laboratory, in the spinal cord-injured population. Fifty-three consecutive traumatically spinal cord-injured patients had weekly urine collection, except when infected or on antibiotics. Each urine sample was tested by a nitrite and leukocyte esterase (LE) dipstick (Chemstrip LN by Bio-Dynamics) and by routine clinical laboratory culture. A total of 169 tests were completed. The correlation coefficients of the LE and the nitrite tests with the culture were 0.604 (P less than 0.001) and 0.663 (P less than 0.001), respectively. The correlation of the combined tests was 0.837 (P less than 0.001). The sensitivity, specificity and positive and negative predictive values of nitrite-LE testing by nursing staff were calculated and compared favorably with published performances of clinical laboratory staff. When measured against the culture, the combined nitrite and LE test had a sensitivity of 79%, specificity of 99% and positive and negative predictive values of 96% and 95%, respectively. The use of a protocol where laboratory culture is performed only when the dipstick test is positive, would reduce the number of cultures by 83%. After extra costs of the additional screen are added, the use of dipstick screening methods by nursing staff can reduce the cost of weekly urine screening by 73%, with a false negative rate of only 4.4%. The expense and complexity of screening for UTI is reduced, response time is minimized and laboratory cultures will have a higher probability of useful clinical information.