The diagnosis of PSC typically involves a combination of blood tests, imaging studies, and liver biopsy. Blood tests may show elevated liver enzymes. Imaging studies such as MRCP (Magnetic Resonance Cholangiopancreatography) or ERCP (Endoscopic Retrograde Cholangiopancreatography) can visualize the bile ducts and reveal characteristic changes. A liver biopsy can provide definitive evidence of inflammation and scarring.