The Frequency of Leukocytes and Nitrites in the Urine of Healthy Adults

The urinalysis (UA) is one of the most commonly utilized tests in the emergency department (ED). In some busy EDs, a UA is routinely ordered by protocol on patients with abdominal pain, and in elderly patients, a UA is often ordered for a variety of chief complaints including dizziness and altered mental status. When these patients, who often do not specifically have symptoms of a urinary tract infection, have a urinalysis demonstrating pyuria or bacteria, it may be interpreted as an atypical presentation of a UTI. However, it is possible that these patients do not have urinary tract infections, but have baseline pyuria or bacteriuria. One prior study found that 5% of sexually active healthy women 18-40 have asymptomatic bacteriuria [1], and the rate of asymptomatic bacteriuria increases with age, such that it is present in 8-10% of women from 70-80 years of age [2]. Moreover, one prior article stated that 30-50% of residents of long term nursing facilities have positive urine cultures at any given time [3].

The above statistics come from the results of urine cultures. In the ED, the decision to treat or not treat a patient for a UTI is not made based upon culture results, but upon a urinalysis (microscopic or dipstick). Only one prior study has looked at the frequency of abnormal urinalyses in healthy individuals, and it found that over a third of asymptomatic women had at least 1+ leukocytes in their urine [4]. This is evidence that a substantial number of people who do not have symptomatic UTIs have UAs that could be interpreted as UTIs. If these results could be replicated and expanded to include a wider group of individuals (males, elderly patients, various races, etc.), it would provide valuable information about how we can better interpret and utilize the results of a UA.

Thus, the investigators propose a prospective study to assess the frequency of abnormal UAs in a wide variety of individuals without acute symptoms.

Urine samples will be obtained from adults with no acute symptoms, and performed urine dipsticks to assess the frequency of leukocytes or nitrites in the urine. Patients will be divided into groups to determine if there are certain factors (gender, age, or medical history) that increase the chance of having leukocytes or nitrites in the urine.