Liver function tests

Liver function tests

1. Liver Function Tests Dr. Roshan Kumar Mahat (PhD Medical Biochemistry) Assistant Professor Department of Biochemistry

2. Functions of Liver Metabolic functions: Carbohydrate metabolism Protein metabolism Lipid metabolism Vitamins and minerals metabolism Nucleic acid metabolism Synthetic functions: Albumin, alpha and beta globulin, prothrombin, coagulation factors, cholesterol, TG, apolipoprotein, etc

3. Secretory function Secretion of bile in intestine Secretion of bilirubin in bile Excretory function Certain exogenous dyes like BSP and Rose Bengal dye are excreted exclusively through live cells. Detoxicating function Exogenous substances- drugs, toxic substances Endogenous substances-ammonia

4. Storage function Vitamin B12, A, D, K, glucose in the form of glycogen Protective function Kupffer cells in the liver remove foreign bodies. Miscellaneous function Blood formation in embryo Forms blood in adults (abnormal states)

5. INDICATION: To detect the presence of liver diseases To distinguishes different types of liver diseases To evaluate the extent of live damages or residual liver function To monitor the response to treatment or the course of the disease.

6. CLASSIFICATION OF LIVER FUNCTION TESTS

7. VD Bergh Reaction and Serum Bilirubin VD Berg reagent contains Sulfanilic acid Sodium nitrite Was introduced by Dutch physician, Abraham van den Bergh When diazotized sulfanilic acid reacts with bilirubin, a purple coloured azobilirubin is produced.

8. There are three possible responses: A direct positive reaction-given by conjugated bilirubin An indirect positive reaction- given by unconjugated bilirubin A biphasic reaction- elevation of both conjugated and unconjugated bilirubin Normal serum gives a negative VD Berg reaction

9. Interpretation Indirect positive Hemolytic jaundice Direct positive Obstructive jaundice Biphasic Hepatocellular jaundice

10. Bile Pigments in Urine/ Faeces Bile pigments in urine: Bilirubin is found in the urine in obstructive jaundice . Bilirubin is not present in urine in most cases of haemolytic jaundice, as unconjugated bilirubin is carried in plasma attached to albumin, hence it cannot pass through the glomerular filter. Bilirubinuria is always accompanied with direct VD Bergh reaction.

11. Bile pigments in faeces : Bilirubin is not normally present in faeces . Some may be found if there is very rapid passage of materials along the intestine Sometimes it is found in faeces of very young infants, if bacterial flora in the gut is not developed. It is regularly found in faeces of patients who are being treated with gut sterilising antibiotics such as neomycin. Biliverdin is found in meconium .

12. Urinary and Faecal Urobilinogen Faecal urobilinogen : Normal=50-250mg/day Increased in hemolytic jaundice-dark coloured stool is passed. Decreased or absent if there is obstruction to the flow of bile in obstructive jaundice-clay-coloured faeces is passed. A complete absence of faecal urobilinogen is strongly suggestive of malignant obstruction.

13. Urinary urobilinogen : Normal=0.64-4 mg/24hr In obstructive jaundice-no urobilinogen is found in the urine. The presence of bilirubin in the urine, without urobilinogen is strongly suggestive of obstructive jaundice either intrahepatic or posthepatic . In haemolytic jaundice- urobilinogen which appears in urine in large amounts. Increased urobilinogen in urine and absence of bilirubin in urine are strongly suggestive of haemolytic jaundice.

14. Determination of Total Plasma Proteins and Albumin and Globulin and A:G Ratio Normal Ranges: Total protein : 5-8gm/dl Albumin : 3.5-5gm/dl Globulin : 2.5-3.5gm/dl A/G ratio : 1.5:1 -2.5:1

15. Interpretations:

16. Estimation of Plasma Fibrinogen:

17. Determination Prothrombin T ime:

18. Other clinical uses: U sed mostly in controlling anticoagulant therapy. Used to decide whether there is danger of bleeding at operation in biliary tract diseases .

19. Prothrombin Index: Normally index is 70 to 100%.

20. AST AND ALT Normal: 15-35IU/L Increased in hepatocellular injury. Chronic hepatitis C Chronic hepatitis B NASH

21. ALP and GGT: ALP=23-92 IU/L, GGT=10-47 IU/L Markers of cholestasis . Increased levels are seen in Infiltrating diseases of liver Bile duct obstruction due to gall stones or carcinoma head of pancreas. It is better to estimate ALP+GGT+ALT to confirm liver disease and/or obstruction.

22. 5’-Nucletidase: Normal range: 2-17IU/L Definite marker of cholestatic liver disease. Not affected in bone diseases. Lactate Dehydrogenase: Normal range: 70-240 IU/L Increased in infectious hepatitis.

23. Serum isocitrate dehydrogenase Normal range: 0.9-4 IU/L Increased in liver diseases but not in obstructive jaundice. Serum cholinesterases : Normal range: 2-5 IU/ml This enzyme is formed in liver and serum activity is reduced in liver cell damage

24. Serum ornithin carbamoyl transferase: Normal =8 to 20 m-IU. The enzyme level is markedly elevated 10 to 200-fold in patients with acute viral hepatitis depending on the severity and also those with other forms of hepatic necrosis. Relatively slight elevations occur in obstructive jaundice, cirrhosis of the liver, metastatic carcinoma, etc. Serum OCT appears to be a specific and sensitive measure for hepatocellular injury

25. Serum Leucine Amino Peptidase (LAP) Normal range is between 15 to 56 m-IU. In viral hepatitis shows mild-to-moderate increase and ranges from 30.0 to 130.0 m-IU. In obstructive jaundice: Marked increase is seen like alkaline phosphatase. Increase is more in malignant obstruction than that of benign obstruction. Marked rise has been seen in Liver cell carcinoma ( Hepatoma ).

26. Serum SHBD ( Hydroxy Butyrate Dehydrogenase) Normal serum HBD between 56 to 125 IU/L In liver diseases elevated levels of this enzyme is observed in acute viral hepatitis. Also elevated level is seen in myocardial infarction

27. Ratio of LDH/SHBD To differentiate the liver diseases and acute myocardial infarction, this ratio has been more useful. Normal= 1.18 to 1.60 Less than 1.18 is observed in most cases of myocardial infarction. Greater than 1.60 is observed in liver diseases.

28. Serum Aldolase and Phosphohexose Isomerase These are both markedly increased in serum of patients with acute hepatitis. No increase is found in cirrhosis, latent hepatitis or biliary obstruction Serum Amylase Studies have shown low serum amylase levels in liver diseases like acute infectious hepatitis

29. Serum Sorbitol Dehydrogenase (SDH) Normal value= less than 0.2 m-IU Striking elevation seen in acute viral hepatitis and carbon tetrachloride poisoning up to 17 m-IU. In chronic hepatitis and in obstructive jaundice: Serum levels of SDH are normal or only slightly elevated

30. Oral Galactose Tolerance Test

31. Interpretations:

32. IV Galactose Tolerance Test

33. Interpretations:

34. Fructose Tolerance Test

35. Interpretations:

36. Epinephrine Tolerance Test

37. Interpretations:

38. Hippuric acid test: Depends on two factors: Ability of the liver cells to produce and provide glycine. The capacity of liver cells to conjugate it with benzoic acid. For reliable result, renal function must be normal.

39. Oral Hippuric A cid T est: [Procedure]

40. Interpretations:

41. IV Hippuric Acid Test: Indication: When there is impairment of absorption. If there is accompanying nausea/vomiting.

42. Procedure:

43. Interpretations:

44. BSP Retention Test The ability of the liver to excrete certain dyes, e.g. BSP is utilised in this test . In normal healthy individual, a constant proportion (10 to 15% of the dye) is removed per minute. Removal of BSP by the liver involves conjugation of the dye as a mercaptide with the cysteine component of glutathione----rate limiting.

45. Procedure: The test is of no value if obstruction of biliary tree exists (obstructive jaundice).

46. Interpretations:

47. Clinical Significance: Useful index of liver damage Most useful in liver cell damage without jaundice Most useful in cirrhosis of the liver Most useful in chronic hepatitis

48. Rose-Bengal Dye Test Rose-Bengal is another dye which can be used to assess excretory function. 10 ml of a 1 per cent solution of the dye is injected IV slowly . Interpretation: Normally 50 per cent or more of the dye disappears within 8 minutes

49. I 131 -labelled Rose-Bengal I 131 -Rose-Bengal has been used where isotope laboratory is present.

50. Interpretation: In parenchymal liver diseases high count in the neck persists and there is hardly a rise in count over abdomen , as the dye is retained.

51. Bilirubin tolerance test: 1 mg/kg body weight of bilirubin is injected IV. If more than 5 per cent of the injected bilirubin is retained after 4 hours, the excretory and conjugating function of the liver is considered abnormal . But the test is not used routinely and extensively due to its high cost

52. Determination of blood NH 3 : Produced by transamination and deamination.

53. Interpretations:

54. Determination of Glutamine in CS Fluid: Glutamine in CS fluid can be estimated by the method of Whittaker (1955 ). The glutamine is hydrolysed to glutamic acid and NH3 by the action of dilute acid at 100 degree centigrade. A correction is made for a small amount of NH 3 produced from urea.

55. Interpretation: increase is very high, ranging from 30 to 60 mg% or more.

56. Monoethyl Glycine Xylidine (MEGX) Test: Lidocaine metabolite formation has been used as an index of hepatic function .

57. Procedure:

58. Interpretation:

59. Antipyrine breath test: Antipyrine like lidocaine is also metabolised by cytochrome P450 system. When given orally it is absorbed from intestine completely, not bound to plasma proteins and metabolised by liver only .

60. Interpretation:

61. Cholesterol- Cholesteryl Ester Ratio the total serum cholesterol is usually low and may fall below 100 mg/dl, whilst there is marked reduction in the % present as esters.

62. TESTS FOR METABOLIC LIVER DISEASE (SPECIAL TESTS) Ceruloplasmin Ferritin and Iron Alpha-1 antitrypsin Beta-2 microglobulin Alpha fetoprotein (AFP) MARKERS OF HEPATIC FIBROSIS Serum hyaluronic acid Procollagen type 1carboxy terminal peptide (PICP) Procollagen type III amino terminal peptide (PIIINP) Matrix metalloproteinases (MMPs) Tissue inhibitors of MMPs (TIMPs) Transforming growth factor beta-1 (TGF Beta-1)