LFTs Flashcards
How is albumin useful in liver disease
• Measure synthetic functions, marker of chronic liver disease
. Hypoalbuminemia occur in liver cirrhosis
How calculate serum ascites albumin gradient saag
Serum albumin-ascites albumin
How interpret serum ascites albumin gradient saag
• High gradient (>1,1g/dL) = portal hypertension, non-peritoneal cause of ascites eg protein losing enteropathy, malnutrition, cirrhosis etc
• low (<1,1) = peritoneal cause of ascites eg Tb abdomen, abdomen cancer
What does prothrombin time (pt) indicate?
Test of plasma clotting activity, reflect activity of vitamin k dependent clotting factors synthesized by liver (thus important marker liver function )
How interpret increased (prolonged) prothrombin time (pt) in association with other coagulation abnormalities? (3)
• Acute liver disease (decreased clotting factor production)
• vitamin K deficiency ( co-factor for factors 2, 7,9,10 )
• malabsorption fat, decreased bile acid synthesis → ADEK excreted in stool
Also: Vit K antagonists, high Conc unfractioned heparin, direct thrombin inhibitors, afibrinogenaemia and dysfibrinogenaemia, dilution coagulopathy, multiple clotting factor deficiencies
What will LFts show upon hepatocyte damage? (4)
• increase AST and alt (leak)
• increase unconjugated bilirubin (decreased ability to conjugate)
• increase alp, GGT (hepatocyte swelling compress intra-hepatic bile ducts)
• increase conjugated bilirubin (decreased bile flow)
How can amminotransferases be used to categorise the severity of liver disease using ULN
Mild <5x ULN (upper limit normal)
Moderate 5-10x
Severe >10x
Acute 10-100
Chronic > 5-10
Name 5 surrogate markers of alcoholic liver disease
• Elevated ggt (disproportionate to any increases in other liver enzymes)
• AST: alt >2!
• hypertriglyceridemia
• increase serum Ig A
• red cell macrocytosis
What type of bilirubin is found in bilirubinuria
Reflects increase in plasma conjugated bilirubin
Always pathological, jaundice
Which type of bilirubin is water soluble
Conjugated
(Unconjugated = lipid soluble)
2 most common causes unconjugated hyperbilirubinemia with pre-hepatic jaundice?
• Haemolysis!
• Gilbert syndrome
Children: physiological jaundice and kernicterus
Name the lab findings found in haemolytic jaundice (8)
• Unconjugated hyperbilirubinaemia
• increase AST (not alt)
• urine urobilinogen increased
• increase reticulocyte count
• decreased haemoglobin
• abnormal RBC morphology on blood film
•Positive Coombs’ (direct antiglobulin) test
• LDH slightly increased, haptoglobin decreased
Symptoms conjugated hyperbilirubinaemia (2)
Dark urine (because water soluble so excreted in kidneys )
Pale stool (if complete biliary obstruction- no stercobilinogen formed)
What is delta bilirubin and why is it clinically relevant(3)
• Conjugated bilirubin bound to albumin
• found in patients with longstanding conjugated hyperbilirubinaemia
• has longer half life similar to albumin thus stays in plasma even after resolution of liver disease. This explains persistence of jaundice in absence of bilirubinaemia
Which 2 enzymes are important in identifying cholestasis?
• Alp
• ggt
