When a dipstick test suggests there's blood in the urine, the next step should be to examine a sample of the urine under a microscope to make sure the dipstick result is accurate, according to medical guidelines - but often the patient is sent directly to see a specialist, or for further testing.

Dipstick tests, in which a narrow strip of plastic is dipped into a urine sample, are very common. Parts of the strip are covered with small squares that turn various colors based on features of the urine, including levels of acidity, proteins, sugar (glucose), and the presence of blood, to name just a few.

The American Urological Association advises that when a dipstick test finds blood in the urine, but the patient is feeling well and has no other symptoms, the result needs to confirmed microscopically before the patient undergoes any further exams, because the dipstick test is not a hundred percent reliable.

But in a study that will appear in the Journal of Urology, Dr. J. Stephen Jones, from the Cleveland Clinic Foundation, and colleagues found that this guideline is often not followed, and as a result, many patients without blood in their urine end up having costly, unnecessary evaluations and testing.

The researchers studied 91 patients who were sent to see urologists because their dipstick test results suggested blood in their urine. In 69 cases, patients' urine samples were not examined under a microscope before their urology referral. At the urologist's office, blood in the urine (a condition known as hematuria) was confirmed in only 17 (25%) of these 69 patients.

Not only that, but 15 patients who didn't really have blood in their urine had imaging studies done before they saw the urologist.

This establishes how frequent it is that patients are at risk of undergoing evaluation for findings that are actually not abnormal, Jones told Reuters Health.

Unfortunately, we were not surprised by the findings, he added. This is common and so we wanted to emphasize the importance of not making decisions based on the urine dipstick alone.

The researchers estimated that the Medicare reimbursement value for the urologic evaluation of the 69 patients who didn't have microscopic confirmation before referral was $44,901. Just one patient (who really did have blood in the urine) had a malignancy.

The take-home message, Jones said, is that invasive tests and x-rays or other imaging studies should not be done until the dipstick test results have been confirmed under a microscope.

SOURCE: Journal of Urology, February 2010.