High anti-HDV IgG/IgM titers plus confirmation with serum<unk>  RNA definitively diagnose, however not widely available
LFTs
AST, ALT > 1000s
Elevated bilirubin
Elevated alk phosphatase
INR
Coagulopathy
Consider acetaminophen level
Acute<unk> anel
Hep A Ab IgM
Hep B cAb IgM
Hep B sAg
Hep B sAb
Hep C Ab
AST, ALT > 1000s
Elevated bilirubin
Elevated alk phosphatase
Coagulopathy
Hep A Ab IgM
Hep B cAb IgM
Hep B sAg
Hep B sAb
Hep C Ab
Hepatitis D
Acetaminophen toxicity 
Hepatitis E
Viral hepatitis
Hepatitis A
Hepatitis B
Hepatitis C
Autoimmune hepatitis