Liver Function Tests Flashcards
Cholestasis
bile is not flowing
Where are transferases found?
AST/ALTFound in hepatocyte. AST specifically is also found in muscle.
Where are alkaline phosphatases found?
The biliary ductal system
Alkaline phosphatase also found in bone, ovary, intestine pancreas and kidney
GGTP more specific for biliary tract
Where is bilirubin found?
The biliary ductal system
Alkaline phosphatase also found in bone, ovary, intestine pancreas and kidney
GGTP more specific for biliary tract
Where is gamma glutamyl transpeptidase
The biliary ductal system
Alkaline phosphatase also found in bone, ovary, intestine pancreas and kidney
GGTP more specific for biliary tract
Where is albumin found
it is ONLY produced in the liver. so, the hepatocyte, hands down.
What is Promthrombin time (INR)?
Measure of hepatic synthetic function through blood clotting. Albumin clotting factor proteins are synthesized exclusively in the liver.
Where is amylase/lipase found? (Even though they are not liver function tests)
The pancreas. Amylase also found in saliva and small intestine. Lipase more specific to the pancreas
Normal values of: AST/ALT : •Bilirubin : Total: , Direct: •Alk. P’tase : •Albumin : •INR: •Amylase : •Lipase :
AST/ALT : 0-40 units/dL Bilirubin : Total: 0.3-1.2 mg/dL, Direct: 0-0.3 Alk. P’tase : 36-92 units/dL Albumin : 3.5-5.5 grams/dL INR: 1.0 Amylase : 0-130 units/L Lipase : 0-95 units/L
SGOT/SGPT = (note that these SGOT/SGPT names should not be seen anymore.)
AST/ALT
What are AST/ALT? What does elevation of these guys mean?
AST/ALT are tranaminases. Elevation of these guys indicates that there is damage to the hepatocytes resulting in leakage of the enzymes into the serum. Think about the heart and troponins and MB-creatine kinase
Why is the normal AST/ALT 0-40 IU’s/dL
This is the case, as normal ranges could be aorund 40, but it may never be 0 since hepatocyte are naturally always dying (natural apoptosis), so you can expect to see some AST/ALT anyway. Note that you measure this stuff by drawing blood, and mixing it with the enzymes used to convert it, giving it a color. You measure the amount of color present.
What is AST? AST/ALT, how do you measure what is normal or abnormal?
Aspartate transaminase. It catalyzes the exchange of an amino group and a alpha keto group. In terms of measuring ahwat is normal and abnormal, you take the base value (usually the 0-40 standard) and see it is multiplied (2x, 5x, 10x, etc). Watch over time. 1000/900 is sky high. 75/85 is low, but it is still above standard and can be just as serious 0….o
What AST/ALT value do patients with chronic liver disease (viral, alcohol, metabolic, NASH, autoimmune) usually present with?
50-70 IU/dl for YEARS. The number is still considered low, but the amount of time is high. NASH is connected to metabolic syndrome…hypertension, hyperlipidemia. With this this high fat diet and with this fat infiltration in the liver, some of the patients get hepatitis…hence, non-alcoholic, steatol, hepatitis (NASH)
Generally ALT is higher than AST. Why? And why is this relationship important?
Liver cells are richer in ALT. If you ever see AST higher than ALT, suspect alcholic related liver disease. Think L for liver. So liver should have more ALT. Going back to AST being higher than ALT in alcoholoics, the reason likely has to deal with fact that ALT has pyridocal 5’phosphate as a cofactor and if deficient, as in alcoholism, the enzyme level is now low.
