Liver Function Tests (LFTs)

Study Notes

LFTs are a group of clinical chemistry tests used to assess liver function and detect liver damage or disease.

Alanine Transaminase (ALT): also known as Serum Glutamic Pyruvic Transaminase (SGPT)
- Normal range: 7-56 IU/L
- Elevated in: hepatitis, liver damage, liver disease
Aspartate Transaminase (AST): also known as Serum Glutamic Oxaloacetic Transaminase (SGOT)
- Normal range: 8-48 IU/L
- Elevated in: liver damage, liver disease, muscle damage
Gamma-Glutamyl Transferase (GGT):
- Normal range: 5-55 IU/L
- Elevated in: liver disease, bile duct obstruction, alcohol abuse

Albumin:
- Normal range: 3.5-5.5 g/dL
- Decreased in: liver disease, malnutrition, inflammation
Prothrombin Time (PT):
- Normal range: 11-13.5 seconds
- Prolonged in: liver disease, vitamin K deficiency, warfarin therapy

Bilirubin:
- Normal range: 0.2-1.2 mg/dL
- Elevated in: liver disease, bile duct obstruction, hemolysis
Alkaline Phosphatase (ALP):
- Normal range: 30-120 IU/L
- Elevated in: liver disease, bone disease, pregnancy

Elevated enzyme tests (ALT, AST, GGT) indicate liver damage or disease.
Decreased synthetic function tests (albumin, PT) indicate liver disease or dysfunction.
Elevated excretory function tests (bilirubin, ALP) indicate liver disease, bile duct obstruction, or bone disease.
Combination of elevated LFTs and physical examination findings can help diagnose liver disease, such as cirrhosis or hepatitis.

Alanine Transaminase (ALT) is also known as Serum Glutamic Pyruvic Transaminase (SGPT).
Normal ALT range: 7-56 IU/L.
Elevated ALT levels are seen in hepatitis, liver damage, and liver disease.
Aspartate Transaminase (AST) is also known as Serum Glutamic Oxaloacetic Transaminase (SGOT).
Normal AST range: 8-48 IU/L.
Elevated AST levels are seen in liver damage, liver disease, and muscle damage.
Gamma-Glutamyl Transferase (GGT) has a normal range of 5-55 IU/L.
Elevated GGT levels are seen in liver disease, bile duct obstruction, and alcohol abuse.

Albumin has a normal range of 3.5-5.5 g/dL.
Decreased albumin levels are seen in liver disease, malnutrition, and inflammation.
Prothrombin Time (PT) has a normal range of 11-13.5 seconds.
Prolonged PT is seen in liver disease, vitamin K deficiency, and warfarin therapy.

Bilirubin has a normal range of 0.2-1.2 mg/dL.
Elevated bilirubin levels are seen in liver disease, bile duct obstruction, and hemolysis.
Alkaline Phosphatase (ALP) has a normal range of 30-120 IU/L.
Elevated ALP levels are seen in liver disease, bone disease, and pregnancy.

Elevated enzyme tests indicate liver damage or disease.
Decreased synthetic function tests indicate liver disease or dysfunction.
Elevated excretory function tests indicate liver disease, bile duct obstruction, or bone disease.
Combination of elevated LFTs and physical examination findings can help diagnose liver disease, such as cirrhosis or hepatitis.