Decrease of urine creatinine in vitro in spinal cord injury patients

Freshly voided urine from 3 spinal cord injury (SCI) patients showed a progressive decline in creatinine concentration over 2 weeks while maintained in the refrigerator. Urine creatinine concentration remained stable in normals, patients with kidney disease and 9 other SCI patients. Mixtures of affected and normal urine showed a progressive decline in creatinine. Boiling or filtering prevented the decline while light centrifugation enhanced the decrease in the sediment but minimized it in the supernatant. Streptococcus fecalis was cultured from all 3 patients' urine, and produced a dramatic fall in creatinine concentration on incubation in broth with creatinine, as well as when added to normal urine. In the refrigerator, however, S. fecalis added to broth with creatinine, as well as to urine did not produce significant fall in creatinine concentration. Thus in certain SCI patients creatinine concentration decreases even when freshly obtained urine is maintained in the refrigerator. The cause of the fall in creatinine may relate to the presence of S. fecalis.