ABNORMAL LFTS

Hepatocellular necrosis:

1. Elevated AST(SGOT), ALT(SGPT).

2. Bilis may be elevated, PT may be prolonged, albumin may be decreased.

3. ALT more specific for liver than AST

4. AST-to-ALT ratio

a. >2: alcohol induced hepatic injury

b. <1: acute or chronic viral hepatitis

1. DDx: alcoholic hepatitis, HAV, HBV, HCV, alpha1-antitrypsin deficiency, autoimmune hepatitis, hemochromatosis, Wilson’s, nonalcoholic steatohepatitis, ischemic hepatitis

2. Additonal tests: ANA, serum ceruloplasmin, Fe/TIBC, hep serologies, SPEP

Cholestatis:

1. Marked elevation in AP (Typically 4-fold)

2. May be elevation of bilis, PT (responsive to Vit K), mild elevation in transaminases.

3. AP non-specific (bone, placenta, intestine, kidney, leukocytes). May be elevated by EtOH, pancreatic dz, MI, uremia, COPD, RA, DM, drugs). Needs to be confirmed by heated AP (BONE BURNS) GGTP, LAP, or 5’-NT.

4. DDx: PBC (AMA+), autoimmune cholangiopathy (AMA-), PSC, extrahepatic obstruction.

5. Additional tests: abd US

Infiltrative process:

1. Elevated AP

2. May be mild elevation of transaminases and bilis.

3. DDx: granulomatous process, ca

WORKUP OF ISOLATED ELEVATED AP:

1. Exclude pregnancy, physiologic causes

2. Check cholestatic markers (GGTP, 5’NT, LAP)

a. normal: consider bone dz (Paget’s, hyperPT, bone mets), ectopic AP.

b. ekevated

i. <3-fold: consider hepatocellular injury

ii. >3-fold: abd US or CT

A. dilated ducts: choledocholithilasis, pancreatic ca, cholangioca, biliary stricture, pancreatitis

B. non-dilated ducts

1. focal hepatic defects: primary or metastatic ca of liver, pyogenic/amebic process

2. normal or diffusely abnormal liver: liver bx or ERCP

Transaminitis >1000: acute viral hep, drug/toxin induced, ischemia

Transaminitis <500-1000: EtOH, extrahepatic obstruction, drug induced.

Direct hyperbilirubinemia: >50% conjugated (direct)

Indirect hyperbilirubinemia: >80% unconjugated (indirect)

Moseley RH, Medical Clinics of North America, 80(5), Sept 1996