Liver Tests/ Hepatitis Serology Flashcards
What are the 3 categories of liver disease?
- Hepatocellular
- Cholestatic
- Infiltrative
What is hepatocellular liver disease?
Injury to the hepatocytes
What is cholestatic liver disease?
Injury of the bile ducts or bile flow obstruction (intra or extra-hepatic compression)
What is infiltrative liver disease?
Liver is invaded or replaced by non-hepatic substances
Ex: tumor, amyloidosis, TB
We didn’t really talk about this in the lecture
Why don’t we call them liver function tests anymore?
Because not all of them tell you about the function of the ~liver~
Which 2 values will definitely be elevated if you have hepatocellular damage?
ALT
AST
What does ALT stand for?
Alanine aminotranserfase
What does AST stand for?
Aspartate transaminase
What are transaminases?
ALT and AST
Which 3 values are definitely going to be elevated if you have cholestatic liver damage?
(Damage to the bile ducts)
- Total bilirubin
- Alkaline phosphatase
- GGT
What does an elevated alkaline phosphatase suggest?
Cholestasis (bile can not flow)
If you have an elevated ALP (alkaline phosphatase), what other 3 values can tell you that it’s definitely coming from the liver?
(There are several places ALP can come from)
ALP isoenzymes-distinguish b/w bone and liver origin
5NP
GGT
What is total bilirubin?
Direct bilirubin + indirect bilirubin
What is fractionated bilirubin?
Fraction of total bilirubin that is direct versus indirect
When is fractionated bilirubin useful?
When standard liver tests are normal and total bilirubin is elevated
Ex: hemolysis, Gilbert’s syndrome
If you have liver disease, what values will you suspect in:
Direct Bilirubin
Indirect Bilirubin
AST/ALT
Direct bilirubin: high
Indirect bilirubin: normal or high
AST/ALT: high
If you have hemolysis, what values do you expect:
Direct Bilirubin
Indirecr Bilirubin
AST and ALT
Hemoglobin
Direct Bilirubin: normal
Indirect bilirubin: HIGH
AST and ALT: normal (the liver is healthy!)
Hemoglobin: LOW
If you have Gilbert’s syndrome, what values do you expect:
Direct bilirubin
Indirect bilirubin
AST and ALT
Hgb
Direct bilirubin: normal
Indirect bilirubin: HIGH
AST and ALT: normal
Hgb: NORMAL
The labs of someone with hemolysis and someone with Gilbert’s syndrome will look very similar (normal direct bilirubin, HIGH indirect bilirubin, normal AST and ALT).
How would you tell them apart?
The person with hemolysis will also have anemia
What is Gilberts syndrome?
You are missing the enzymes in your liver that conjugate bilirubin
(Conjugated bilirubin= direct bilirubin
Unconjugated bilirubin= indirect bilirubin)
What ratio will be over 2 if someone has Alcoholic liver disease
AST
______
ALT
(STop ALcohol)
When is GGT useful?
- When ALP is elevated, it confers liver specificity
2. When AST/ALT is more than 2, it supports diagnosis of alcoholic liver disease 🥂
What 2 values directly reflect liver function?
Albumin
PT/INR
(Broken liver wont be making clotting factors or albumin)
Which is more specific to the liver:
AST or ALT?
ALT
Where are the highest levels of ALT found?
Liver
Is there a direct relationship between the severity of liver disease and transaminase levels?
No
Do normal liver tests mean the liver is normal?
No, it means to repeat it (????)
This is one of her “pearls”
I’m never going to mayo
What should you do if you get elevated LFTs but your patient has no symptoms?
Repeat the test but with the patient fasting
If just ONE of your values is elevated and everything else is normal, what should that make you suspect?
Something OTHER than the liver is messed up
What is a non-hepatic source of a high bilirubin?
RBCs
Hemolysis, bleeding etc
What is a non-hepatic source of high AST?
Muscle, heart, kidney, brain
What is a non-liver source of ALT?
Muscle, heart, kidneys
What is a non-liver source of LDH?
Literally everything
Its in your whole body. Tissue death would cause elevated LDH