LIVER FUNCTION TESTS
Roles of Liver - CORRECT ANSWERS-- Synthesis of proteins, amino acids, vitamins,
fats
- Storage- glycogen, triglycerides, iron, copper, lipid soluble vitamins
- Glucose regulation (gluconeogenesis)
- Detoxification
- Excretory function- Bile production/drainage
What are Liver Function tests?
Most Common Tests (found in a hepatic function panel): - CORRECT ANSWERS-- AST
(aspartate aminotransferase)
- ALT (alanine aminotransferase)
- Albumin
- Alkaline Phosphatase
- Total Protein
- Total Bilirubin
- Direct Bilirubin
What are Liver Function tests?
Other labs - CORRECT ANSWERS-- Usually ordered in response to abnormal findings
in your Hepatic Function Panel
-- LDH (lactate dehydrogenase)
-- GGT (gamma glutamyl transpeptidase)
-- 5'nucleotidase
-- Coagulation factors (PT/PTT/INR)
-- Acute Hepatitis Panel
What the Tests Show - CORRECT ANSWERS-- Patterns In LFT abnormalities help
point to their possible etiology:
A) HepatoCellular Injury:
- AST/ALT/LDH
B) Cholestasis/Biliary Excretory Function:
- Bilirubin/ Alkaline Phosphatase/ GGT/ 5'Nucleotidase
C) Hepatic Synthetic Function:
- Albumin/ PT/ Coagulation factors
- Remember you can not rely on the LFTs alone
- Can be normal in some cases, even with a disease process
, - One must clinically correlate
Approaching Liver Function Tests - CORRECT ANSWERS-- As always History and
Physical will be important to your evaluation of LFTs
- Important Questions:
-- FMH (any issues with liver, bilirubin or anemia)
-- Social History
--- Occupation
--- Travel
--- Alcohol or Illicit Drug Use
--- Sexual Activity
-- PMH/PSH
--- Home Medications
--- Surgeries
Physical Exam Clues - CORRECT ANSWERS-- Cachexia/temporal wasting
- Spider nevi/palmar erythema, gynecomastia, caput medusa
- Ascites
- Hepatic Encephalopathy
- Virchow's node/Sister Mary Joseph's node
- Pleural Effusion
- Neurologic issues
- JVD
- Parotid gland enlargement
- Jaundice
- Asterixis
Aminotransferases - CORRECT ANSWERS-- AST/ALT are released from hepatocytes
in response to damage
- Possible sources:
-- Toxins/EtOH
-- Viral Hepatitis
-- Ischemia/Hypoperfusion
-- Malignancy
- Elevations indicate possible differentials
AST - CORRECT ANSWERS-- Aspartate aminotransferase
-- Normal value: 8-45 U/L
-- Formerly SGOT (Serum Glutamic-Oxaloacetic Transaminase)
-- Synthesized by multiple organs: Liver, heart, muscles...
-- Also found in Mitochondria
-- Half life of 48 hours, in acute hepatitis may elevate higher than ALT, then after 48
hours ALT will be higher
ALT - CORRECT ANSWERS-- Alanine aminotransferase
-- Normal value : 7-55 U/L
-- Formerly SGPT (Serum Glutamic-Pyruvic Transaminase)
- Unlike AST primarily produced by the liver hepatocytes
Roles of Liver - CORRECT ANSWERS-- Synthesis of proteins, amino acids, vitamins,
fats
- Storage- glycogen, triglycerides, iron, copper, lipid soluble vitamins
- Glucose regulation (gluconeogenesis)
- Detoxification
- Excretory function- Bile production/drainage
What are Liver Function tests?
Most Common Tests (found in a hepatic function panel): - CORRECT ANSWERS-- AST
(aspartate aminotransferase)
- ALT (alanine aminotransferase)
- Albumin
- Alkaline Phosphatase
- Total Protein
- Total Bilirubin
- Direct Bilirubin
What are Liver Function tests?
Other labs - CORRECT ANSWERS-- Usually ordered in response to abnormal findings
in your Hepatic Function Panel
-- LDH (lactate dehydrogenase)
-- GGT (gamma glutamyl transpeptidase)
-- 5'nucleotidase
-- Coagulation factors (PT/PTT/INR)
-- Acute Hepatitis Panel
What the Tests Show - CORRECT ANSWERS-- Patterns In LFT abnormalities help
point to their possible etiology:
A) HepatoCellular Injury:
- AST/ALT/LDH
B) Cholestasis/Biliary Excretory Function:
- Bilirubin/ Alkaline Phosphatase/ GGT/ 5'Nucleotidase
C) Hepatic Synthetic Function:
- Albumin/ PT/ Coagulation factors
- Remember you can not rely on the LFTs alone
- Can be normal in some cases, even with a disease process
, - One must clinically correlate
Approaching Liver Function Tests - CORRECT ANSWERS-- As always History and
Physical will be important to your evaluation of LFTs
- Important Questions:
-- FMH (any issues with liver, bilirubin or anemia)
-- Social History
--- Occupation
--- Travel
--- Alcohol or Illicit Drug Use
--- Sexual Activity
-- PMH/PSH
--- Home Medications
--- Surgeries
Physical Exam Clues - CORRECT ANSWERS-- Cachexia/temporal wasting
- Spider nevi/palmar erythema, gynecomastia, caput medusa
- Ascites
- Hepatic Encephalopathy
- Virchow's node/Sister Mary Joseph's node
- Pleural Effusion
- Neurologic issues
- JVD
- Parotid gland enlargement
- Jaundice
- Asterixis
Aminotransferases - CORRECT ANSWERS-- AST/ALT are released from hepatocytes
in response to damage
- Possible sources:
-- Toxins/EtOH
-- Viral Hepatitis
-- Ischemia/Hypoperfusion
-- Malignancy
- Elevations indicate possible differentials
AST - CORRECT ANSWERS-- Aspartate aminotransferase
-- Normal value: 8-45 U/L
-- Formerly SGOT (Serum Glutamic-Oxaloacetic Transaminase)
-- Synthesized by multiple organs: Liver, heart, muscles...
-- Also found in Mitochondria
-- Half life of 48 hours, in acute hepatitis may elevate higher than ALT, then after 48
hours ALT will be higher
ALT - CORRECT ANSWERS-- Alanine aminotransferase
-- Normal value : 7-55 U/L
-- Formerly SGPT (Serum Glutamic-Pyruvic Transaminase)
- Unlike AST primarily produced by the liver hepatocytes
