Dip-Stick Testing for Urinary Tract Infections
Urinary tract infections (UTIs) are a common problem for persons with spinal cord injury. Signs and symptoms of UTI may include cloudy urine, increased Spasticity, fever, chills, and urinary frequency and Incontinence.
Sometimes the signs and symptoms are subtle, and your doctor may order a urinalysis, which usually includes dip-stick testing, a method to detect the presence of nitrites and/or leukocyte esterase. Nitrate is normally present in the urine and is changed into nitrite in the presence of certain bacteria, usually those belonging to the Enterobacteriaceae family. Leukocycte esterase is an enzyme that indicates the presence of white blood cells in the urine.
The presence of nitrites or leukocyte esterase indicates that a UTI is present, and a urine culture will be ordered to determine the type and quantity of bacteria in the urine.
We have just completed a study of UTIs in 55 persons with SCI. As part of our study, we compared the results of dip-stick testing to the results of urine cultures to determine whether dip-stick testing is a reliable indicator of UTI. We found that neither the presence of nitrite or leukocyte esterase predicted the presence of significant bacteriuria (> 100,000 cfu) and had low sensitivities. These results suggest that dip-stick testing for nitrites or leukocyte esterase is not a reliable indicator of UTI in persons with SCI and should not be used by clinicians to decide whether or not to obtain a urine culture because it might delay necessary treatment.
Published in the Winter 2001 issue of Spinal Cord Injury Update
Diana D. Cardenas, MD