Liver Function Tests Flashcards
Causes of liver disease
Infection Adverse drug reaction Alcohol abuse Obesity Cancer
Signs of hepatic disease
Jaundice Pruritis Nausea and vomiting Hepatomegaly Ascites Spider naevi Dark urine and pale stools
Normal blood concentrations
Bilirubin 5-17micromol/l Hepatocellular: Alanine (ALT) <50iU/l Obstruction: Alkaline phosphatase 39-17iU/l Gamma-glutamyl transpeptidase 0-70iU/l male 0-40iU/l female Synthetic function: Albumin 30-48g/l Coagulation INR 1-1.2
Stages of haem breakdown
Haem-> iron+globin | Biliverdin | Insoluble bilirubin | Liver | Soluble bilirubin Biliary excretion
Conditions where bilirubin might be altered
Biliary obstruction (choleostasis)
Hepatocellular damage
Haemolysis
Conditions where aminotransferases maybe altered
Hepatocellular damage
Leak out of damaged cells-> large increase in blood
Detection of paracetamol overdose
ALT more specific to liver damage
Conditions where Alkaline phosphatase might be altered
Present in canicular and sinusoid membranes of liver
Increased in choleostasis
But also produced by bone and placenta so increased in pregnancy
Raised in infiltration of the liver-> metastasis
Conditions where Gamma GT’s might be altered
Present in manny tissues Increased by induction Alcohol Carbamazepine Barbiturates Phenytoin Rifampincin Increased in choleostasis May be increased in cellular damage Look at mean corpuscular volume as we'll
Conditions where albumin might be altered
Measure of synthetic activity of the liver
Indicates a change over longer term-> 16-24 days
International normalised ratio
Prothrombin time
Indicates synthetic activity
Coagulation factors have a short half life so indicates change acute and chronic
Hepatitis LFT results
ALT and AST raised ALP increased or normal Bilirubin increased or normal GGT increased or normal Albumin only effected in late stages INR raised or normal
Cholestasis LFT results
ALP raised GGT raised Bilirubin raised as not excreted ALT and AST raised or normal Albumin normal, synthetic function not effected by choleostasis INR raised or normal
LFT chronic liver disease
GGT raised Bilirubin raised Albumin decreased INR increased ALP, ALT, AST raised or normal
Pre hepatic jaundice
Problem before liver
Insoluble bilirubin produced faster than the liver can conjugate it
Haemolytic anaemias such as spherocytosis
Gilbert’s syndrome-> decreased UDP- glucuranosyl transferase-> conjugated bilirubin
Hepatocellular jaundice
Transaminases leak out
Liver can’t conjugate bilirubin
Reduced excretion