Background and objective: The amount of procalcitonin eliminated in the urine and the plasma disappearance rate of procalcitonin were evaluated in patients with normal and impaired renal function, because patients with sepsis are a main target group for procalcitonin measurement, and these patients often develop renal dysfunction.
Methods: Elimination of procalcitonin in the urine (microgram 12 h-1) was measured in 76 patients. In another 67 patients, the 50% plasma disappearance rate (t1/2, h) was evaluated 48 h after peak concentrations (procalcitonin > 2 micrograms L-1). Renal function was assessed by creatinine clearance.
Results: Procalcitonin elimination in the urine was significantly reduced in patients with severe renal dysfunction. However, the plasma disappearance rate correlated only weakly with renal dysfunction (Spearman's rank correlation R = -0.36, P = 0.004, regression t1/2 = 49.87-0.15 creatinine clearance). The 25% quartile and median were 25.2 h and 30.0 h in patients with normal renal function, and 36.3 h and 44.7 h in patients with severely impaired renal function (creatinine clearance < 30 mL min-1).
Conclusions: Renal elimination of procalcitonin is not a major mechanism for procalcitonin removal from the plasma. Although the plasma disappearance rate may be prolonged up to 30-50% in some patients with renal dysfunction, clinical diagnostic decisions may not be severely influenced by this moderate prolongation of procalcitonin elimination. We conclude that procalcitonin can be used diagnostically in patients with renal failure as well as in those with normal renal function.