Routine urinalysis after blunt abdominal trauma won’t help find urogenital injury, Dutch researchers say.

“With the advancements made in CT scanning, there is now much greater accuracy in the detection (or ruling out) of injury to the urogenital system,” Dr. J. Carel Goslings from Academic Medical Center in Amsterdam told Reuters Health.

“In this study,” Dr. Goslings added, “we found the value of the routine performance of urinalysis in patients with a blunt trauma mechanism to be limited.”

The retrospective study involved 1815 patients. Most patients — 1031, or 57% — also had imaging studies, according to a paper online September 16th in Emergency Medicine Journal.

Among the patients who had imaging studies done, 795 (77%) had no hematuria, 220 (21%) had microscopic hematuria, and 16 (2%) had macroscopic hematuria.

Of the 220 patients with microscopic hematuria, eight had abnormal urogenital imaging studies, but only three of the eight had clinical consequences. Another eight patients with microscopic hematuria did have clinical consequences despite normal-looking imaging.

There were 332 patients who had urine collected but no imaging studies. In this group, 278 patients (84%) had no hematuria. In the 54 patients (16%) who did have microscopic hematuria, there were no clinical consequences, according to the authors.

Two hundred sixty-eight patients (15%) had urogenital imaging but no urinalysis. Only 10 had abnormal findings; four of the 10 had clinical consequences.

Ten percent of patients had neither urine collection nor imaging.

“The potential danger of performing urinalysis without imaging is to miss clinically relevant injuries (e.g., bleeding sites in the kidney parenchyma), which can only be shown by imaging,” the authors wrote. “Bypassing urinalysis and going straight for imaging…results in clinical consequences in 1.5% of the patients (4 out of 268). This is comparable to the percentage of clinical consequences in the patients who receive both urinalysis and imaging (2%; 22 out of 1031).”

They added, “The remaining 0.5% difference in clinical consequences consists of relatively minor consequences such as additional imaging and re-evaluation at the outpatient department, and this indicates little added value of the performance of urinalysis.”

Dr. Goslings told Reuters Health that the researchers “advise omitting this investigation as a routine part of the assessment of trauma patients, given that (good) imaging facilities are available in the hospital.”

But in specific circumstances, urinalysis might still be appropriate. Repeating by email some points from the paper, Dr. Goslings wrote, “In particular, patients with specific trauma mechanisms (e.g., fall from height, fall from horse or direct blow to the flank) or patients with a suspicion of pelvic (ring) injuries or thoracolumbar spinal cord injuries might benefit from urinalysis.”

“Future studies should focus on identifying the subgroups of patients in whom urinalysis is helpful,” Dr. Goslings added.