Lect 12 Liver Laboratory Values.pdf

Liver Laboratory Values Chapter 16 Lec 12 Liver Laboratory Values • Liver Function Test – LFTs • Most common – – – – – – Bilirubin Aminotransferases Alkaline Phosphatase Albumin Prothrombin Serum Ammonia Total Serum Bilirubin • Product of heme degradation • Normal = < 1.5 mg/dl • Liver typical...

Liver Laboratory Values Chapter 16 Lec 12 Liver Laboratory Values • Liver Function Test – LFTs • Most common – – – – – – Bilirubin Aminotransferases Alkaline Phosphatase Albumin Prothrombin Serum Ammonia Total Serum Bilirubin • Product of heme degradation • Normal = < 1.5 mg/dl • Liver typically conjugates (makes bili water soluble) and excretes bilirubin in bile .(‫يقترن الكبد عادة )يصنع ماء الصفراء‬ ‫قابل للذوبان( ويفرز البيليروبني في الصفراء‬ – Increased due to: • Overproduction (hemolysis) • Defect in hepatic uptake (liver specific) • Defect in hepatic conjugation (liver specific) Indirect Serum Bilirubin • Unconjugated bilirubin (in serum, tightly bound to albumin) • Normal = 0.1-0.5 mg/dl • Increased due to: (‫ بإحكام مرتبط باأللبومني‬،‫البيليروبني غير املقترن )في املصل‬ – – – – – Enzyme system Inherited defects Drugs Hepatitis Cirrhosis Direct Serum Bilirubin • Conjugated bilirubin • Normal = <0.3 mg/dl • Increased due to: – Depressed excretion – Cholestasis – Benign - refers to a condition, tumor, or growth that is not cancerous. – Congenital Serum Aminotransferase Studies • Most frequently used to assess liver function – AST, previously known as SGOT ((serum glutamic-oxaloacetic transaminase) – ALT, previously known as SGPT (serum glutamic-pyruvic transaminase) Serum Aminotransferase Studies • Alanine Aminotransferase • ALT (SGPT) • 7 - 40 U/L • Most sensitive to liver injury over time • Aspartate Aminotransferase • AST (SGOT) • 30-40 U/L • Less specific • Also elevated in cardiac and muscle damage Serum Enzyme Studies • GGTP (GGT) – – – – – – Gamma-Glutamyl Transpeptidase Normal = 30 U/L Present in many tissues Effected by disease states Sensitive indicator of liver disease Also increased in alcoholic liver disease as well as increased with alcohol consumption Serum Enzyme Studies • Alkaline Phosphatase – Normal = 30 – 95 U/L – Increased in hepatic disease & malignancy & chronic obstruction of the biliary duct. Also increased in bone disease, bone trauma & bone growth Serum Albumin • • • • • • Normal = 3.5 – 5 g/dl Main export protein Transport protein Synthesized in liver Maintains plasma oncotic pressure Decreased with liver disease – Significant decrease expected with cirrhosis, chronic hepatitis, edema, and ascites Prothrombin Time • • • • • • PT Normal = 12.4 – 14.4 seconds Clotting factor Synthesized in liver Vitamin K dependent PT prolonged with liver disease (increase PT) Serum Ammonia • Liver converts ammonia to urea – Urea cycle • Normal = 19-60 mcg/dl • Levels rise with liver failure Cholesterol • Produced by the liver • Normal = <200 mg/dl • Levels decrease/increase with liver disease Diagnostic Testing • • • • Computed tomography scan - CT Magnetic resonance imaging - MRI Abdominal ultrasound Cholangiogram – radiograph of the bile ducts made after the ingestion or injection of a radiopaque substance. • Liver biopsy (a helpful tool in assessing the degree of liver disease and its complications) Summary • Many different lab values are associated with liver disease • No one lab value tells the whole story • Becoming familiar with normal values will become second nature • Understanding these labs help you determine what nutrition interventions are needed.