LFT interpretation Flashcards
What is alanine transaminase (ALT) generally a marker of?
Hepatocellular injury - it is specific to the liver
What is alkaline phosphatase (ALP) generally a marker of?
Cholestasis
If there is a raised ALP, what other enzyme is it important to check alongside?
Gamma-glutamyl transferase (GGT)
What does a raised GGT indicate? (2)
- Biliary epithelial damage and/or bile flow obstruction.
2. It can also be raised in response to alcohol and drugs such as phenytoin
What does a raised ALP and GGT indicate?
Indicates strong likelihood raised ALP is of hepatic origin/cholestasis
If ALP is raised but GGT is normal, what can this indicate? (4)
- Bony metastases / primary bone tumours (e.g. sarcoma)
- Vitamin D deficiency
- Recent bone fractures
- Renal osteodystrophy
What are the causes of isolated jaundiced (when the patient is jaundice, but ALP and ALT are normal)? (2)
- Gilbert’s syndrome
2. Haemolysis
What are livers main synthetic functions? (4)
- Synthesis of albumin
- Synthesis of clotting factors
- Conjugation/elimination of bilirubin
- Gluconeogensis
If a person is jaundiced, how can the colour of their urine and stools indicate whether the cause is pre-hepatic, hepatic or post-hepatic?
Unconjugated urine is water soluble and therefore doesn’t affect the colour of the patient’s urine. Conjugated bilirubin, however, can pass into the urine as urobilinogen, causing the urine to become darker.
In cholestasis, less conjugated bilirubin enters the gut, resulting in stools becoming pale (known as steatorrhoea).
What would be the appearance of a patients urine and stool sample if they have post-hepatic jaundice?
Dark urine and pale stools
How would the urine and stool sample of a patient with hepatic jaundice present?
Dark urine and normal stools
What is the function of albumin, and what is its half life?
Albumin is synthesised in the liver and helps to bind water, cations, fatty acids and bilirubin. It also plays a key role in maintaining the oncotic pressure of blood. It has a half life of 20 days
What can be the causes of low albumin and low protein? (5)
- Advanced cirrhosis
- Alcoholism
- Protein malnutrition
- Chronic inflammation
- Rena//gut/skin loss
What may be the cause of low albumin levels but normal protein levels? (1)
Infection
What may be the cause of low albumin levels but high protein levels? (1)
Myeloma
If ALT and AST levels are both raised, but ALT > AST, what does this tend to indicate?
Chronic liver disease
If ALT and AST levels are both raised, but AST > ALT, what does this tend to indicate? (2)
Cirrhosis
Acute alcoholic hepatitis
What are the common causes of acute hepatocellular damage? (3)
- Poisoning (paracetamol overdose)
- Infection (Hepatitis A and B)
- Liver ischaemia
What are the common causes of chronic hepatocellular injury? (4)
- Alcoholic fatty liver disease
- Non-alcoholic fatty liver disease
- Chronic infection (Hepatitis B or C)
- Primary biliary cirrhosis
What are the less common causes of chronic hepatocellular injury? (3)
- Alpha-1 antitrypsin deficiency
- Wilson’s disease
- Haemochromatosis
If LFTs are deranged, what further tests can be requested to complete a full liver screen? (14)
- Coagulation screen
- Hepatitis serology (A/B/C)
- Epstein-Barr Virus (EBV)
- Cytomegalovirus (CMV)
- Anti-mitochondrial antibody (AMA)
- Anti-smooth muscle antibody (ASMA)
- Anti-liver/kidney microsomal antibodies (Anti-LKM)
- Anti-nuclear antibody (ANA)
- p-ANCA
- Immunoglobulins – IgM/IgG
- Alpha-1 Antitrypsin – Alpha-1 Antitrypsin deficiency
- Serum Copper – Wilson’s disease
- Ceruloplasmin – Wilson’s disease
- Ferritin – Haemochromatosis
