Abnormal LFTs

Question 1

What is part of the LFT test and what is ordered separately?

Answer 1

What is part of LFT test: ALT, ALP, Albumin, BR

What are ordered separately: GGT, AST

• AST and ALT usually ↑ or ↓ in tandem 🡪 no need to monitor both to trend!
• GGT is ONLY ordered when ALP is high
• If ALP and GGT are high 🡪 think of hepatobiliary problem
• If only ALP is high and GGT is low 🡪 think of bone problem

Question 2

What are liver function markers?

Answer 2

• Total Bilirubin (<18 normal)
• PT/INR
• Albumin
• AFP 🡪 HCC

Question 3

What is the normal AST: ALT?

Answer 3

0.8

Question 4

What is the normal range of ALT?

Answer 4

Male: 10-30 (Males are more attractive in their 30s)

Female: 10-20 (Females are more attractive in their 20s)

Question 5

What are the differentials if ALT >1000?

Answer 5

Acute viral hepatitis (HAV, HBV, HEV), Ischaemic Hepatitis (eg: in shock), Budd Chiari, toxin / drug induced (eg: paracet)

Question 6

What are the differentials if ALT >10 000?

Answer 6

Ischemic liver damage, toxin/drug-induced liver damage (eg: paracetamol)

Question 7

What if the differentials if it is an AST predominant picture (AST>ALT) if both ALT& AST are elevated?

Answer 7

Cirrhosis

Alcoholic liver disease: AST:ALT > 2, normal ALP, raised GGT. ↑ GGT in the context of ↑ AST & ALT localizes to the liver

Fulminant Wilson’s Disease - AST:ALT > 4

Dengue a/w thrombocytopenia

Question 8

What if the differentials if it is an ALT predominant picture (AST>ALT) if both ALT& AST are elevated?

Answer 8

Drug-induced hepatitis

HBV/HCV: AST & ALT <1000 usually

Hemochromatosis: Fe/TIBC > 45

Alpha-1 antitrypsin deficiency: History of emphysema out of proportion to age and smoking Hx

Question 9

What is the R factor [(ALT/Upper limit of ALT) / (ALP/ Upper limit of ALP)] <2 mean? What investigations to perform?

Answer 9

Elevated ALP and GGT disproportionate to AST & ALT suggestive of cholestasis

ALP typically >4 times upper limit

Perform hepatobiliary USS to assess liver parenchyma and bile duct

Presence of ductal dilatation= Biliary Obstruction 🡪 Choledocholithiasis, Cholangiocarcinoma, Pancreatic cancer, PSC,

No Ductal Dilatation = Hepatocellular Dysfunction

1) +/- ↑ALP: Biliary Epithelial Damage secondary to; Hepatitis (↑ALT), Cirrhosis (↑PT, ↓Alb)
2) ↑↑ALP:
- Intrahepatic Cholestasis: Medication, TPN, PBC, Sepsis, Post-Operative, intrahepatic cholangiocarcinoma. To diagnose PBC use the AMA test 🡪 Anti Mitochondrial Ab +ve indicates PBC (specificity is ~100%)
- Infiltrative Pattern (↑↑ALP, Near Normal BR, AST, ALT): think of lymphoma, sarcoid, TB, syphilis

Question 10

What is the R factor [(ALT/Upper limit of ALT) / (ALP/ Upper limit of ALP)] 2- 5 mean

Answer 10

a mix of cholestatic + liver disease

Question 11

What is the R factor [(ALT/Upper limit of ALT) / (ALP/ Upper limit of ALP)] >5 mean

Answer 11

consistent w liver disease

Question 12

What is the normal ALP and GGT values?

Answer 12

ALP: 40-100
GGT: 5-60

Question 13

How do you differentiate between bone and liver ALP?

Answer 13

ALP isozymes can be fractionated (aka separated) via heat

Bone ALP is non-heat stable, whereas Liver ALP is heat stable

Hence “Liver lives, Bone burns”