Formerly Called Serum Glutamate-Pyruvate Transaminase (SGPT)
Origin of Transaminases (Aminotransferases)
Liver: AST and ALT
Cardiac and Skeletal Muscle: AST only
Thyroid: AST only
Sensitivity/Specificity of Transaminases (Especially ALT) for the Differentiation of Liver Disease from Other Disorders Depends on the Cutoff Value Chosen to Define an Abnormal Result
ALT Levels Correlate with the Degree of Abdominal Adiposity Vary Between the Sexes
AST and ALT Upper Limits of Normal Vary Between Laboratories: due to differing reference standards used
Optimal ALT Cutoff Value (Male): 29 IU/L (Hepatology, 2012) [MEDLINE]
Optimal ALT Cutoff Value (Female): 22 IU/L (Hepatology, 2012) [MEDLINE]
Elevated Alkaline Phosphatase Associated with a Normal Gamma-Glutamyl Transpeptidase or 5′-Nucleotidase Suggests a Non-Hepatic Source of the Alkaline Phosphatase
Fractionation of Alkaline Phosphatase: may also be used to determine origin
Heat-Labile Alkaline Phosphatase: suggests bone origin (“bone burns”)
AST: wide variability, but usually <2x upper limit of normal (rarely >10x upper limit of normal)
ALT: wide variability, but usually <2x upper limit of normal (rarely >10x upper limit of normal)
Acute Viral/Toxic Hepatitis with Associated Hyperbilirubinemia
AST: >25x upper limit of normal
ALT: >25x upper limit of normal
Ischemic Hepatitis (Hypoxic Hepatitis, Shock Liver) (see Ischemic Hepatitis)
AST: >50x upper limit of normal
ALT: >50x upper limit of normal
LDH: markedly elevated (usually)
Etiology of Mildly-Moderately Elevated Transaminases (Transaminitis <15x Upper Limit of Normal)
Hepatic Disease
AST-Predominant (AST/ALT Ratio ≥1)
Alcohol-Related Liver Disease
General Comments
AST/ALT Ratio >2: Suggestive of Alcoholic Liver Disease (Especially in the Setting of Elevated Gamma-Glutamyl Transpeptidase) (Dig Dis Sci, 1985) [MEDLINE]
AST/ALT Ratio >3: Even More Strongly Suggests Alcoholic Liver Disease (Dig Dis Sci, 1979) [MEDLINE]
Cosyntropin (Cortrosyn) Stimulation Test (ACTH Stimulation Test) (see Cosyntropin Stimulation Test): in appropriate patients with relevant symptoms/signs, this is useful to diagnose adrenal insufficiency (see Adrenal Insufficiency)
Evaluation for Kaiser-Fleisher Rings: useful to diagnose Wilson disease (see Wilson Disease)
Hepatic Ultrasound is Useful to Diagnose Hepatic Steatosis (see Hepatic Steatosis)
Doppler Studies are Required to Exclude Hepatic Vein Thrombosis (Budd-Chiari Syndrome)
Liver Biopsy (see Liver Biopsy): may be required if remaining work-up is non-diagnostic
Utility of Liver Biopsy in the Setting of Chronic LFT Abnormalities (Am J Gastroenterol, 2000) [MEDLINE]
Liver Biopsy May Aid in a Diagnosis, But the Results Infrequently Alter the Presumptive Pre-Biopsy Diagnosis and No Proven Therapy Exists for the Vast Majority of Patients
Risks and Benefits of Liver Biopsy Should Be Carefully Considered, Especially in Settings Where Investigational Therapies are Not Available
Liver Biopsy is Probably Indicated in Patients with Undiagnosed Persistent Transaminitis >2 Upper Limit of Normal
Serum Aldolase (see Serum Aldolase): in patients with suspected muscle disorder
Serum Alpha-1 Antitrypsin Level (see Serum Alpha-1 Antitrypsin): useful to diagnose alpha-1 antitrypsin deficiecy
Serum Creatine Kinase (CK) (see Serum Creatine Kinase): in patients with suspected muscle disorder
Serum Iron and Total Iron Binding Capacity (Transferrin Saturation) (see xxxx)
Transferrin Saturation >45% Warrants Obtaining a Serum Ferritin (see Serum Ferritin)
Serum Ferritin Should Not Be Obtained as an Initial Test Since it is an Acute Phase Reactant and is Less Specific than the Transferrin Saturation
Serum Ferritin >400 ng/mL (>900 pmol/L) in Male and >300 ng/mL (<675 pmol/L) in Female Supports (But Does Not Confirm) the Diagnosis of Hemochromatosis (see Hemochromatosis)
Urinalysis (see Urinalysis): to diagnose proteinuria in pregnant patients
Urinary Copper Excretion: useful to diagnose Wilson disease (see Wilson Disease)
Viral Serologies/Studies
Anti-Hepatitis A IgM Antibody
Hepatitis B Surface Antigen (HBsAg)
Anti-Hepatitis B Core Antigen IgM Antibody (Anti-HBc)
Anti-Hepatitis C Antibody
Hepatitis C Viral RNA
Anti-Hepatitis D Antibody: in patient with acute or chronic hepatitis B (see Hepatitis B Virus)
Anti-Hepatitis E Antibody: in patients with residence in or travel to hepatitis E endemic regions (Asia, Africa, Middle East, Central America) or in pregnant patients (due to the high rates of acute liver failure in pregnant women with hepatitis E vural infection)
Cases of Hepatitis E Have Also Been Reported in Developed Countries without a History of Foreign Travel
Hepatic Ultrasound is Useful to Biliary Ductal Dilation (Consistent with the Diagnosis of Extrahepatic Cholestasis): however, biliary ultrasound may fail to show biliary ductal dilation in cases with partial bile duct obstruction, as well as cirrhosis and primary sclerosing cholangitis (where scarring prevents the intrahepatic ducts from dilating)
In General, Absence of Biliary Ductal Dilation Indicates Intrahepatic Cholestasis
Etiology of Markedly Elevated Alkaline Phosphatase Elevation (≥4x Upper Limit of Normal) (see Serum Alkaline Phosphatase)
Hepatic Ultrasound is Useful to Biliary Ductal Dilation (Consistent with the Diagnosis of Extrahepatic Cholestasis): however, biliary ultrasound may fail to show biliary ductal dilation in cases with partial bile duct obstruction, as well as cirrhosis and primary sclerosing cholangitis (where scarring prevents the intrahepatic ducts from dilating)
In General, Absence of Biliary Ductal Dilation Indicates Intrahepatic Cholestasis
Heat stability of human serum alkaline phosphatase in bone and liver diseases. Clin Chim Acta. 1972 Oct;41:329-34 [MEDLINE]
The SGOT/SGPT ratio–an indicator of alcoholic liver disease. Dig Dis Sci. 1979;24(11):835 [MEDLINE]
Serum gamma-glutamyl transpeptidase and chronic alcoholism. Influence of alcohol ingestion and liver disease. Dig Dis Sci. 1985;30(3):211 [MEDLINE]
An assessment of the role of liver biopsies in asymptomatic patients with chronic liver test abnormalities. Am J Gastroenterol. 2000;95(11):3206 [MEDLINE]
Upper limits of normal for alanine aminotransferase activity in the United States population. Hepatology. 2012;55(2):447 [MEDLINE]
An association of elevated levels of alkaline phosphatase and gamma-glutamyl transpeptidase with acute cholangitis. Hepatogastroenterology. 2014 Mar-Apr;61(130):291-5 [MEDLINE]
