Other Blood Tests

Question 1

What are the tests for hyponatremia?

Answer 1

- Plasma osmolality
Low = true
Normal = false
High = dilutional
- Urinary sodium and osmolality (to determine if problem in kidneys or elsewhere)

Question 2

What does >1000 increase in ALT tell us?

Answer 2

> 1000

• Toxin-induced hepatitis e.g. paracetamol
• Acute viral hepatitis (HepA/B/E, EBV)
• Liver ischaemia

Question 3

What are U+E’s results that indicate dialysis in AKI?

Answer 3

A - acidosis pH <7.1
E - electrolyte abnormalities (hyperkalaemia, hyponatremia, hypercalcaemia) - K >6.5 or ECG changes
I - intoxicants (methanol, lithium, salicylates)
O - overload (acute pulmonary oedema)
U - uraemia - urea >60, uraemic pericarditis or encephalopathy

Question 4

What does 300-500 ALT/AST mean?

Answer 4

• Chronic viral/alcoholic/autoimmune hepatitis

- Biliary obstruction

Question 5

What does a <300 increase in ALT/AST mean?

Answer 5

• Cirrhosis
• NAFLD
• Hepatocellular carcinoma
• Haemochromatosis/Wilson’s

Question 6

What does a marked increase (4x normal) in ALP mean?

Answer 6

Cholestasis e.g. gallstones, primary biliary cholangitis, primary sclerosing cholangitis, pancreatic cancer, drugs

Question 7

What does a moderate increase (2x normal) in ALP mean?

Answer 7

• Hepatitis
• Cirrhosis
• Infiltration e.g. Hepatocellular carcinoma, liver abscess etc

Question 8

What is the role of gamma GT marker?

Answer 8

Mirrors ALP so can be used to confirm if a rise in ALP is of hepatic origin.
Raised with alcohol abuse and enzyme-inducing drugs.

Question 9

What are the causes of unconjugated hyperbilirubinaemia?

Answer 9

• Haemolysis - increased RBC breakdown (haemolytic anaemia)
• Impaired hepatic uptake (drugs, HF)
• Impaired conjugation (Gilbert’s syndrome, physiological neonatal jaundice)

Question 10

What are the causes of conjugated hyperbilirubinaemia?

Answer 10

• Hepatocellular dysfunction (liver disease)

- Impaired hepatic secretion (cholestasis)

Question 11

What is the summary of LFT results?

Answer 11

• Hepatocellular: AST/ALT ^ to ^^^
• Cholestatic: ALP/GGT + bilirubin ^ to ^^^
• Cirrhosis: bilirubin ^ to ^^^, albumin decreased to very decreased, INR ^ to ^^^

Question 12

Jaundice + normal urine + normal stools =

Answer 12

Pre-hepatic cause (usually due to erythrocytes haemolysis)

Question 13

Jaundice + dark urine + normal stools =

Answer 13

Hepatic cause (usually due to liver injury e.g. drugs/hepatitis)

Question 14

Dark urine + jaundice + pale stools =

Answer 14

Post-hepatic/obstructive cause (due to blockage of bile ducts e.g. pancreatitis, pancreatic cancer)

Question 15

What does ALT > AST mean?

Answer 15

Chronic liver disease

Question 16

What does AST>ALT mean?

Answer 16

Cirrhosis and acute alcohol hepatitis