One study showed that renal elimination was the major pathway for the clearance of PCT,[34] whereas another study found a high level of PCT in patients with renal dysfunction without signs of infections.[35] Yet another study indicated that the plasma clearance rate of PCT correlated weakly with renal function.[36] The liver is an essential component of the body's metabolic system, and the bilirubin level may reflect severity of liver damage, meaning that the liver may be one location for elimination of PCT. This evidence concerns the gene CALCA and infection.