Liver Function Tests

Question 1

Patient Question: “What percentage of my liver is working?”

Answer 1

Hard to answer. Don’t measure % like the kidneys. But can estimate causes of liver disease, operative risks, and life-expectancies/survival estimates

Question 2

Two major causes of liver disease: hepatocellular injury and cholestatic injury

Question 3

What are some general complications of Liver Disease?

Answer 3

• Synthetic impairment
• Cholestasis – impairment of bile flow anywhere in the flow
• Decreased clearance (like with ammonia- high ammonia is toxic!)
• Portal hypertension – portal blood is shunted around the liver and not processed by the liver

Question 4

Question 5

What do elevated aminotransferases suggest?

Answer 5

hepatocellular injury

Question 6

What does elevated alk phosphate suggest?

Answer 6

more biliary damage (or bone)

Question 7

What are some liver tests that measure clearance?

Answer 7

bilirubin and ammonia

Question 8

What are some liver tests that measure synthetic capacity?

Answer 8

clotting factors

albumin

cholesterol (late complication of severe dysfunction)

Question 9

What are the aminotransferases?

Answer 9

• Aspartate aminotransferase (AST)
• Alanine aminotransferase (ALT)
• Increase associated with liver cell injury or death (release these after injury/death)

Question 10

AST is also elevated in _____

Answer 10

muscle injury (marathon runner). ALT is more specific for liver injury

•Marked elevations of both associated with primary hepatocellular injury

Question 11

Where does alk P come from?

Answer 11

bile ducts. Correlates with intrahepatic and extrahepatic injury or obstruction

Question 12

What pts normally have elevated Alk P?

Answer 12

pregnant women

Question 13

What are the 3 main isozymes of Alk P?

Answer 13

gut, liver, and bone

Question 14

Answer 14

Question 15

What bilirubin level leads to juandice usually?

Answer 15

3+

Question 16

Answer 16

Question 17

This pt. was given an IM injection in a person with high INR, and bleeding resulted

Answer 17

Femoral a. stick for BAG leading to bleeding in a person with high INR

Question 18

What is the half-life of albumin?

Answer 18

20 days

Question 19

the Child-Pugh score (sometimes the Child-Turcotte-Pugh score) is used to assess the prognosis of chronic liver disease, mainly cirrhosis. Although it was originally used to predict mortality during surgery, it is now used to determine the prognosis, as well as the required strength of treatment and the necessity of liver transplantation.

Answer 19

Question 20

What is MELD?

Answer 20

The Model for End-Stage Liver Disease, or MELD, is a scoring system for assessing the severity of chronic liver disease. It was initially developed to predict mortality within three months of surgery in patients who had undergone a transjugular intrahepatic portosystemic shunt (TIPS) procedure, and was subsequently found to be useful in determining prognosis and prioritizing for receipt of a liver transplant.This score is now used by the United Network for Organ Sharing (UNOS) and Eurotransplant for prioritizing allocation of liver transplants instead of the older Child-Pugh score

Question 21

What are the components of MELD?

Answer 21

• International Normalized Ratio (INR) – standardized measure of Prothrombin time, hepatic synthetic function
• Bilirubin
• Creatinine. Often low in pts. With liver disease, and when high you’re likely to die
• Added Na+ recently. When Na+ is low in cirrhosis pts, they don’t live as long

MELD = 3.8 [Ln Bilirubin (mg/dl)]+11.2 [Ln INR] + 9.6 [Ln Creatinine (mg/dl)] + 6.4