Chapter 5 Liver function tests

1. Chapter 5 Liver function tests • Liver function tests include the tests of protein metabolism, the tests of bilirubin metabolism, the tests of dye intake and excretion, the tests of serum enzymes and the tests of viral hepatitis. • In general , the tests currently available can be divided into two categories: the tests of hepatic function or capacity and the screen-ing tests that suggest the presence and /or type of liver disease. Specific diagnostic tests such as serologic tests for hepatitis infection are also covered in this chapter.

2. Tests of protein metabolism • Serum total protein (TP),albumin (A) and globulin (G) • The normal range of TP, A and G is 60-80g/L, 40-55g/L and 20-30 g/L . The normal ratio of A to G (A/G) is 1.5-2.5 : 1 • Increased G and decreased A (reversed A/G) can be seen in chronic hepatitis, cirrhosis, hepatic neoplasm .

3. Serum protein eletrophoresis • A 0.61-0.71 , a1 0.03-0.04 , a2 0.06-0.1 , B 0.07-0.11 , r 0.09-0.18 • cirrhosis and hepatic neoplasms: A , a1, a2, B decrease , r increase • hepatitis: in acute hepatitis : normal level, • in chronic hepatitis : A decrease, r increase

4. hepatic neoplasm markers: alpha fetoprotein (AFP): < 25ug/ L , > 500 ug /L : primary hepatocellular carcinoma carcinoembryonic antigen (CEA): 0-5 ug /L , increased CEA: liver metastatic carcinoma or other carcinomas of the gastrointestinal system abnormal prothrombin (APT): < 20 ug/L, increased APT : primaryhepatocellular carcinoma

5. Testsof bilirubin metabolism • serum total bilirubin(STB), serum direct bilirubin (SDB) and serum indirect bilirubin(SIB) • STB : 1.7-17.1 umol/L (normal), 17-34 umol/L (latent jaundice), hyperbilirubinemia • SDB: 0-6.8 umol/L (normal), SIB: 1.7-10.2 umol/L (normal), SDB/STB 20% (normal), • urea bilirubin : normal: (-), when SDB > 34 umol/L (+) • urobilinogen: normal : (- ~ +)

6. Clinical significance of tests in bilirubin metabolism(umol/L) STB SDB SIB SDB/STB URO UBI normal 1.7~17.1.7 ~10.2 0~6.8 20% -~+ - hemolysis <85 mild significant <20% ++~+++ - hepatitis 17~200 medium medium >35% +~++ + biliary 200~500 significant mild >60% - ++ obstruction

7. Dye intake and excretion • Indocyanine green retention rate (ICGR): 15 mim: < 10% • chronic hapatitis: 15~20% • cirrhosis : 35%

8. Serum enzyme tests • aspartate ( AST, SGOT) and alanine ( ALT, SGPT) . The serum transaminase are sensitive tests of liver damage. And the height of the activity reflects the severity of hepatic necrosis. • ALT: < 35U/L, AST: <40U/L • elevated ALT,AST : acute hepatitis (viral or toxic ), chronic hepatitis and cirrhosis,biliary obstruction

9. ` • Alkaline phosphatase (ALP): • Serum levels are elevated in association with cholestasis, partial or complete bile duct obstruction, bone regeneration, and also with neoplastic , infiltrative, and granulomatous liver disease. An isolated elevated ALP level may be the only clue to partial obstruction of the common bile duct. • ALP : 30-130 U/L ( 36-92 U/L) • elevated ALP: bile duct obstruction, primary hepatocellular carcinoma, hepatitis

10. r-glutamyl transferase (r-GT): • 3~17U/L(M), 2~13 U/L(F) • elevated r-GT: hepatic neoplasm • obstructive jaundice • hepatitis

11. Tests of viral hepatitis • Viral hepatitis is caused by five main viruses: hepatitis viruses A, B, C, D and E. In present, hepatitis A , hepatitis B and hepatitis C are more common. The ability to detect the presence of viral components in hepatitis B and C and antibodies to components of hepatitis A,B, C and D has enabled considerable progress to be made in the study of the epidemiology of viral hepatitis. These so-called viral markers can be diagnostic of the cause of acute viral hepatitis.

12. serologic markers of viral hepatitis agent markers definition significance HAV anti-HAV antibody to HAV IgM type current or recent infection or convalescence IgG type current or previous infection , confers immunity HBV HBsAG HBV surface antigen positive in acute or chronic infection HBeAG e antigen, a component transiently positive of the HBV core in acute Hepitis B ,may reflects presence of viral replication and infectivity

13. anti-HBe antibody to e antigen transiently positive in convalescence, may be persistently present in chronic cases, reflects low infectivity anti-HBc antibody to core antigen IgG type positive in all acute and chronic cases, reliable marker of infection ,past or current IgM type reflects active viral replication , not protective anti-HBs antibody to surface antigen positive in late convalescence, confers immunity, after injection of Hepitis B vaccine HCV anti-HCV antibody to HCV positive after clinical onset(15 week), not protective, persists in chronic infection

14. Automatic biochemistry analyzer: • Using the analyzer, we can detect 14 items of liver and renal function tests easily. • ALT, AST, CHO, ALP, GGT, TBIL, DBIL, TP, ALB, GLB and BUN, CRE, GLU, UA

15. Case analysis • History and physical examination: This 48-year-old man had complained of abdominal pain and intermittent fever for 3 months. The pain was usually felt in the right upper quadrant. His appetite was not good and lost his body weight apparently. He once suffered from hepatitis ten years ago. Physical examination revealed the patient who appeared chronically ill with icteric selera. The liver was enlarged to 2 cm below the costal margin with tenderness, and the spleen was enlarged to 3 cm below costal margin .

16. Laboratory data: Hb 90g /L, WBC 8.0×109/L, PC 90×109/L, ALT 120U/L, AST 200U/L,ALP 255U/L, TP 55g/L, A 25g/L, Y 40%, TBI 55umol/L, DBI 38umol/L, URO (++), UBI (+),AFP 600ug/L, HBsAg (+), HBeAg (+), anti-HBc IgM (+) • Question: • What is your diagnosis for this patient? • Which kind of jaundice this patient has? • How to evaluate this patients liver function? • What is etiological classification for his hepatitis?