[Determination of creatinine in drained liquid. Urinary leak or lymphocele?].

Background: Liquid collections around the renal graft that are displayed in 51% of cases implicate a diagnostic challenge and a risk for graft function. We undertook this study to determine the usefulness of creatinine concentration measurement in drainage in patients with renal transplantation.

Methods: We selected patients with surgically corrected urinary leak and patients with lymphocele from November 1, 1999, to November 30, 2008, in whom we determined the creatinine concentration in liquid drainage, plasma and urine.

Results: We included five patients with urinary leak and six patients with lymphocele. Two patients had urinary leak before the lymphocele. The t value of the plasma creatinine (Pcreat), drainage (Dcreat) and urine (Ucreat) was 0.89, 0.045 and 0.63, respectively. The diagnostic criteria of urinary leak represented a value between the creatinine of the drainage and plasma (D/Pcreat) >6, between urine and drainage (U/Dcreat) <3 and between urine and plasma (U/ Pcreat) <7. When we compared both groups the χ(2) values were 0.018, 0.007 and 0.094, respectively.

Conclusions: There is a statistically significant difference among the creatinine drainage liquid values. Our study shows that D/Pcreat ratio >6 after the first week or U/Dcreat ratio <3 at any time during the postoperative period represents a six-times higher possibility of urinary leak.