APPRAISAL OF THE STABILITY OF LEUKOCYTES IN REFRIGERATED URINE

There is limited evidence that urinary leukocytes are rapidly destroye d in alkaline hypotonic urine. We assessed the stability of leukocytes in urine specimens provided by 90 children with neurogenic bladder wh o attended a meningomyelocele clinic. No significant correlation was f ound between urine specific gravity and leukocyte survival after an in terval of 4 h in a sample of 30 specimens from these patients. The sur vival of leukocytes was determined at 2 h and at 4 h in aliquots of th ese 30 specimens directly, and after adjustment to pH values of 5.0, 7 .0, 8.0, 8.5, and 9.0. Statistically significant leukocyte destruction only occurred at pH 9.0 at 2 h (16%), at pH 8.5 at 4 h (19%), and at pH 9.0 at 4 h (57%). Only one of a further sample of 180 routine speci mens had both a pH of greater than or equal to 8.5 and an interval to laboratory examination of > 2 h. No specimen had a specific gravity of <1.002, and 93.9% had values of greater than or equal to 1.005. Urine pH and tonicity were not therefore important determinants of leukocyt e stability in refrigerated samples examined within 4 h from this clin ic population.