Clinical type

Ratio of ALT elevation to ALP elevationa (R)

First-line tests

Second-line tests

Hepatocellular

or mixed

R ≥5

2 <R <5

– Acute viral hepatitis serologic studies, HCV RNA

– Autoimmune hepatitis serologic studies

– Imaging studies (eg, abdominal US)

On case-by-case basis:

– Ceruloplasmin

– Serologic studies for less common viruses (HEV, CMV, EBV)

– Liver biopsy

Cholestatic

R ≤2

Imaging studies (abdominal US)

On case-by-case basis:

– Cholangiography (either endoscopic or MR-based)

– Serologic studies for primary biliary cholangiopathy

– Liver biopsy

a R = ALT/ULNALT to ALP/ULNALP.