LABORATORY IN HEPATOBILIARY DISEASES

1. LABORATORYIN HEPATOBILIARY DISEASES Dr. Sebati ÖZDEMİR Division of Gastroenterology

2. LIVER CHEMISTRY TESTS Liver chemistry tests fall into three main categories: • Tests that reflect hepatobiliary injury.(Hepatocellular injury and cholestatic injury). • Tests that evaluate the functional status of the liver. • Tests that define the etiology of liver disease.

3. LIVER CHEMISTRY TESTS • Aminotransferase (ALT and AST) • The reflection of hepatocellular damage • Alkaline Phosphatase and γ-glutamyltransferase (GGT) • The reflection of cholestasis and/or hepatic infiltrates • Bilirubins • The presence and severity of jaundice • Albumin and prothrombin time • The reflection of hepatic synthetic function

4. Common Serum Liver Chemistry Tests Liver chemistry test Clinical implication of abnormality Alanine aminotransferase …(ALT)......Hepatocellular damage Aspartate aminotransferase..(AST)….Hepatocellular damage Prothrombin time…………(PT)……….Synthetic function Albumin……………………..…...….…..Synthetic function Bilirubin: Cholestasis, impaired conjugation,or biliary obstruction, or isolated-familial hyperbilirubinemia (discussed in the lecture of JAUNDICE) Alkaline phosphatase…....(AP)………Cholestasis or biliary obstruction or infiltrative disease γ-glutamyltransferase……(GGT)…....Cholestasis or biliary obstruction Bile acids……………………………….Cholestasis or biliary obstruction 5'-Nucleotidase……………………..…Cholestasis or biliary obstruction Lactat dehydrogenase……(LDH).......Hepatocellular damage; not specific for hepatic disease

5. Hepatocellular Injury Alanine aminotransferase (ALT) formerly (SGPT) • It is found primarily in the liver. Aspartate aminotransferase (AST) formerly (SGOT) • It is found in the liver, cardiac muscle, skeletal muscle, kidneys, brain, pancreas, lungs, leukocytes, and erythrocytes. (in decreasing order of concentration)

6. Etiology of mild ALT or AST elevationsLess than 5 times normal Hepatic: ALT-predominant • Chronic hepatitis B • Chronic hepatitis C (*) • Acute viral hepatitis (A–E, EBV, CMV) • Steatosis/steatohepatitis • Hemochromatosis • Medications/toxins • Autoimmune hepatitis • Alpha1-antitrypsin deficiency • Wilson's disease • Celiac disease

7. Etiology of mild ALT or AST elevationsLess than 5 times normal Hepatic: AST-predominant • Alcohol-related liver injury • Steatosis/steatohepatitis • Cirrhosis Nonhepatic • Hemolysis • Myopathy • Thyroid disease • Strenuous exercise

8. Etiology of severe ALT and AST elevationsGreater than 15 times normal • Acute viral hepatitis (A-E viruses, herpes) • Medications/toxins • Ischemic hepatitis • Autoimmune hepatitis • Wilson's disease • Acute Budd-Chiari syndrome • Hepatic artery ligation

9. Cholestatic Injury • Alkaline phosphatase • It is found in the liver, bone (the both more than 80% of total AP), placenta, intestine, kidneys, and leukocytes. • Gamma-glutamyltransferase (GGT) • It is found in the cell membranes of several tissues (BUT NOT IN BONE!.. )(Therefore GGT is a valuable test whether an alkaline phosphatase elevation is “LIVER OR BONE” origin) • It is a very sensitive indicator of the presence or absence of hepatobiliary disease. • 5'-Nucleotidase

10. Causes of Elevated Serum Alkaline Phosphatase HEPATOBILIARY • Bile duct obstruction • Cholestatic liver disease (primary biliary cirrhosis, primary sclerosing cholangitis) • Medications • Hepatocellular carcinoma (HCC) • Hepatic metastasis • Infiltrating diseases of the liver • Hepatitis • Cirrhosis

11. Causes of Elevated Serum Alkaline Phosphatase NONHEPATIC • Bone disease • Pregnancy • Childhood growth • Lymphoma and other malignancies • Infection/Inflammation

15. Functional Status • Albumin • Hypoalbuminemia is due to a decreased hepatic synthesis (liver disease), or increased renal losing (nephrotic syndrome) • Prothrombin Time (PT) • The liver synthesizes coagulation factors I, II, V, VII, IX, XII and XIII. • PT depends on tha activity of factors I, II, V, VII and X. • (K vit. II, VII, IX and X).