#Laboratory assessment of liver function

Synthesised by hepatocytes

Liver synthesises all clotting factors except factors III (tissue factor), IV (calcium), VIII and vWF.

Bile secretion facilitates vitamin K absorption.

↓ synthesis → hypoalbuminaemia

↓ clotting factor synthesis → prolonged PT / INR

↓ vitamin K synthesis → ↓ deficiency of clotting factors II/VII/IX/X → prolonged PT / INR

Inflammatory states increases escape of albumin into interstitium.

Malnutrition → decreased albumin synthesis.

Nephrotic syndrome → increased albumin loss via kidneys.

Vitamin K deficiency (e.g. due to cholestasis or diet)

Warfarin

Coagulopathy e.g. DIC

Loss of clotting factors e.g. nephrotic syndrome

Liver synthesises and stores glycogen, predominantly from lactate/pyruvate.

Generates glucose through glycogenolysis and gluconeogenesis.

Involved in insulin clearance.

Amino acids are deaminated in the liver, producing ammonia which is converted to urea or glutamine in hepatocytes.

Acute liver failure:
Hypoglycaemia + lactataemia due to failure to convert lactate to glucose via gluconeogenesis.

Chronic liver failure:
Hyperglycaemia due to impaired insulin clearance leading to insulin insensitivity.

Decreased action of the urea cycle
→ impaired conversion of ammonia to urea
→ hyperammonaemia

• Diet
• Diabetes
• Catecholamines
• Drugs: insulin, oral hypoglycaemics

Increased production:

• UGIB

Decreased elimination:

• valproate toxicity
• urea cycle disorders
• distal RTA