Measuring liver function

Question 1

what do liver function tests involved?

Answer 1

detecting the levels of several biochemical markers in the bloodstream to identify patients who are suffering from liver or billary tract disease

Question 2

what do LFT substances measured include?

Answer 2

Bilirubin
Alanine aminotransferase (ALT)
Aspartame aminotransferase (AST)
Gamma-glutamate transferase (GGT)
Alkaline phosphate (ALP)
Proteins
Globulins
Albumin

Question 3

what happens to liver enzymes when the liver cells are damaged?

Answer 3

they leak into the blood

Question 4

what does ALT and AST levels provide?

Answer 4

an indication of the degree of inflammation as well as causes of hepatocellular damage

Question 5

what do ALP and GGT increase indicate?

Answer 5

suggest the presence of obstructive bilary disease

Question 6

what is hepatitis?

Answer 6

a term used to describe inflammation of the liver. can be caused by a viral infection or because the liver is exposed to harmful substances

Question 7

what is cholestasis?

Answer 7

a condition where bile cannot flow from the liver to the duodenum (mechanical- block in billiary tree vs metabolic - turnover of bilirubin)

Question 8

what is cirrhosis?

Answer 8

scarring of the liver as a result of continuous, long term liver damage

Question 9

how is bilirubin carried in blood unconjugated?

Answer 9

carried by albumin to the liver where it is conjugated to make more water soluble before secreted in bile

Question 10

at what levels is jaundice visible?

Answer 10

above 35umol/L

Question 11

in severe jaundice what can levels rise to?

Answer 11

500umol/L

Question 12

what does it mean if there is more conjugated bilirubin than unconjugated?

Answer 12

bilary obstruction

Question 13

what does it mean if there is equal conjugated and unconjugated bilirubin?

Answer 13

hepatocellular damage is likely

Question 14

how can conjugated bilirubin be measured?

Answer 14

using urine sampling over 24 hrs

Question 15

what is palmer erythema?

Answer 15

reddening of the skin on the palmer aspects of the hands

Question 16

what is ascites?

Answer 16

excessive accumulation of fluid in the abdominal cavity
- weight gain
- discomfort
- nausea and appetite loss

Question 17

what is spider naevi?

Answer 17

swollen blood vessels

Question 18

what is unconjugated bilirubin?

Answer 18

bound to albumin, water insoluble does not appear in urine

Question 19

what is conjugated bilirubin?

Answer 19

diglucoronide, water soluble, appears in urine

Question 20

what is ALT?

Answer 20

• present in high concentration
• found in cardiac and skeletal muscle
• specific marker of hepatocellular damage
• Low ALT suggests vitamin B6 deficiency

Question 21

what is AST?

Answer 21

• Present in liver, heart, kidneys, skeletal muscle and RBCs
• raised in shock
• less specific for liver disease
• AST levels are also raised in pregnancy and after exercise

Question 22

what is GGT?

Answer 22

• Present in liver, kidneys, prostate and pancreas
• levels are raised in all types of liver and biliary tract disease and also pancreatic cancer
• most useful in patients at risk of liver disease due to alcoholism
• levels return when drinking has stopped or if it persists, this means liver damage is sustained or patient is still drinking

Question 23

what is ALP?

Answer 23

• produced in liver, bile ducts and gut
• levels raised in diseases of liver or biliary tract, highest levels found in obstructive jaundice
• usually raised in cirrhosis and liver cancers

Question 25

what does serum albumin levels indicate?

Answer 25

- typically low in chronic liver disease - indicated how well the liver is making proteins - in acute condition the concentration may remain within range - levels decrease after surgery, affected by hydration (over- lowers), decreases in pregnancy and with age