Urinary lactate dehydrogenase isoenzyme analysis in adult population

This investigation was a systemic study on an adult population of urinary lactate dehydrogenase (LDH) isoenzyme analysis for the distinction between upper and lower urinary tract infections. The study included 160 urine samples from patients and healthy individuals. On the basis of clinical symptoms, urinary bacterial colony counts, renal function tests and radiologic findings, the adults were divided into pyelonephritis group, cystitis group, pelvic lesion group, and control group. This technique correctly identified 23 of 26 patients with pyelonephritis by the presence of elevated LDH-V (over 10 percent) and all of 12 patients with cystitis by the presence of elevated LDH-I (over 60 relative units) but low LDH-V (below 10 percent or lower than LDH-I). In the pelvic group, the results of eight patients were consistent with cystitis and four with pyelonephritis. Our study confirms the sensitivity and specificity of the LDH isoenzyme technique for the differential diagnosis of urinary tract infection on adult patients and is consistent with previous studies on pediatric patients. However, one should be cautious to interpret the results of LDH isoenzymogram before extra-urinary tract lesions are excluded.