liver function tests

1. LET YOUR LIGHT SHINE
VAMSI KUMAR DEP NO 17-PML-01
ALPHONASA THOMAS DEP NO 17-PML-019

2. VAMSI KUMARALPHONSA THOMAS

4. imp...
• The choice of biochemical tests to measure liver function mostly
depend on the purpose of investigation
• The clinical history of the subject is often a guiding factor in this
regard
• A single test in isolation may have a little diagnostic value
• Frequently a combination of laboratory investigations are emloyed in
LFT such as bilirubin in serum both conjugated/unconjugated
• (ALT, AST, ALP, GGT, 5'NT, Protein like Albumin and Globulin)

6. ① Excretory function: bile pigments, bile salts and cholesterol are excreted in bile
into intestine.
② Metabolic function: liver actively participates in carbohydrate, lipid, protein,
mineral and vitamin metabolisms.
③ Hematological function: liver is also produces clotting factors like factor V, VII.
Fibrinogen involved in blood coagulation is also synthesized in liver. It
synthesize plasma proteins and destruction of erythrocytes.
④ Storage functions: glycogen, vitamins A, D and B12,and trace element iron are stored in
liver.
⑤ Protective functions and detoxification: Ammonia is detoxified to urea. kupffer cells of
liver perform phagocytosis to eliminate foreign compounds. Liver is responsible for the
metabolism of xenobiotic.

7. What is Purpose of LFTs?
• LFTs alone do not give the physician full information, but used in combination
with a careful history, physical examination (particularly ultrasound and CT
Scanning), can contribute to making an accurate diagnosis of the specific liver
disorder.
• Different tests will show abnormalities in response to
liver inflammation
liver injury due to drugs, alcohol, toxins, viruses
Liver malfunction due to blockage of the flow of bile
Liver cancers

8. LFTs are divided into
such as serum albumin, bilirubin, and prothrombin,

Classified based on the major functions of liver:
① Excretion: Measurement of bile pigments, bile salts.
② Serum enzymes: Transaminase (ALT, AST), alkaline phosphate(ALP), 5’-
nucleotidase, LDH isoenzyme.
③ Synthetic function: Prothrombin time, serum albumin.
④ Metabolic capacity: Galactose tolerance and antipyrine clearance
⑤ Detoxification :synthesis of hipuric aicd from sodium beenzoate

10. TESTS TO ASSAY EXCERATORY FUNTION OF LIVER

11. 1. Excretion : Bilirubin
•Bilirubin is the main bile pigment that is
formed from the breakdown of heme in red
blood cells. The broken down heme travels
to the liver, where it is secreted into the
bile by the liver.

13. 1. serum bilirubin:
• Normally, a small amount of bilirubin circulates in the blood. Serum bilirubin is
considered a true test of liver function, as it reflects the liver's ability to take up,
process, and secrete bilirubin into the bile.
A. indirect bilirubin
(normal value = 0.3 - 1.2 mg/dl
B. direct bilirubin
(normal value ≤ 0.4 mg/dl)
C. total bilirubin
Normal value for = 0.3- 1.2 mg/dl.

14. VAN DEN BERG REACTION
• ♣ Direct Bilirubin + Diazotized Sulfanilic Acid → Azobilirubin (Redish purple)
• ♣ total bilirubin + dimethylsulfoxide(DMSO)+methanol +diazotized sulfanilic
acid to form azobilirubin.
• Indirect bilirubin react with diazotized sulfanilic acid after addition of
methanol.
•
• The absorbance of the reaction mixture at 555 nm is directly proportional to
the concentration of direct bilirubin.

20. TESTS BASED ON ENZYMES DRIVED FROM LIVER
• several enzymes are released from dieased hepatocytes
• they are be cytosol,mitochodrial or membrane assiciated enzymes
• type of enzyme released depends on sevierity and specificity dieases
of liver
• the amount of enzyme in plasma is directly proptional to the
sevierity to the liver damage.
• so such enzyme tests are useful in evaluation of liver functions as
well as dieases affecing liver.

22. • 1.Alanine amino tranferase (ALT) a.k.a SGPT serum glutamate
pyruvate transaminase
• 2.Aspartate transaminase (AST) a.k.a SGOT serum glutamate
oxaloacetate transaminase
• these 2 enzymes are present in the liver
• these 2 have different half lifes.
• the half life of ALT is 47 hours and AST is 17 hours
• IMP- LIVER CONTAINS MORE AMOUNT OF ALT compared to AST and
is specific in nature.
• AST is not so spacific since it is present in heart and skeletal muscle.
• so, AST test useful only in the absence of SECONDRY DIEASE
• how ever due to their present in livver cells both the enzymes are
elevated in liver dieases

23. CONTINUE....
• The degree of elevation indicates QUANTUM OF HEPATIC CELLULARR
DAMAGE and return to normal level is suggestive recoovering
• due to its higher half life ALT return to normal slowley ...
• in acute hepatitis its level is HIGHER than AST
• in ALCHOLIC liver AST level is HIGHER than ALT level....
• NORMAL VALUES
AST=5-45IU/L
ALT=5--40IU/L
normal AST/ALT rartio is 0.8
*>in mi i.e AST INCREASE than ALT
*< in acute hepatic damage i.e ALT increase than AST

25. B.ALP ALKALINE PHOSPATASE
• It is an membrane bound enzyme concentrated in sinusoids and endothelium
of portal venous system...
• only small amount are present in bile canaliculli.
• 2.Any type of damage to bilary tree such as obstruction leads to increase in the
synthesis of ALP by hepatocytes which in turn leaks in to plasma
• i.e as a result plasma ALP increases.
• in extra hepatic obstruction , elevaztiion of ALP is moe than 3 fold and in intra
hepatic obstruction elevation is about 2.5 fold....
• but ALP is also present in bone, brain and GUT...
so how to inrepret the results

26. C.GAAMA GLUTAMYL TRANSPEPTIDASE (GGT)
• It is the membrane bound enzym
• GTT is elevated in all forms of liver dieases
• about 10 - 30 tiimes it is elevated in bilary obstruction..
• IT IS MORE SENSITIVE THAN ALP
• It is onlyy moderatly elevated in infective hepatitis.
• alcoholic cirhossis is another liver diease in which GGT is elevated
• in FATTY LIVER also GTT levvel elevated...

27. D.5'NUCLEOTIDASE
• It is another membrane bound
enzyme...
• several fold increase in 5'NT
activity is found in conditions
there is obstruction to follow of
bile which may be either intra
hpatic orr extra hepatic
• normal or moderatly elevated
5'NT acttivity is found in
infectiive hepatitis
• in bilary cirrhosis also 5'NT
activity is elevated

29. GALACTOSE TOLARANCE TEST
• Liver is involved in the coonversion of GALACTOSE is metabolically converted to
GLUCOSE
• liver is the only organ involved in diosposal of galactose
• so, measurment of of galactose clearence by liver is useful in assesing hepatic
function
• after an intravenous galactose injection, b;;ood samples are collected for
every 10 in untill 1 hour
• galactose is measured in blood sample
• normally liveer clears galactose wiith in 10 -15 minutes
• delay of clerance indicates CIRHOOSSIS and HEPATTITIS..

32. SODIUM BENZOATE TEST
• The liver is the major site for the
metabolism of
xenobiotics(detoxified agents)
• measurment of hippuric acid
synthesis is an ideal test for the
assesiing the detox functionn
the liver
• hippuric acid is produced in the
liver when Benzoic acid is
combined with Glycin..

34. SYNTHETIC FUNCTION OF LIVER
• Liver is involved in synthesis of many plasma proteins like BLOOD
CLOTTING FACTORS, LIPO PROTEINS, ETC..
• SYNTHESIS of these componds may be affected in pathological
conditions of liver..
• i..e their concentration in plasma mayy decrease, however of their
long HALF LIIFE and REGENARATION capacity of liver decrease may
bbe apparent only on long standing liver dieases
• THESE INCLUDE

35. • In severe liver diseases, hypoalbunemia occurs.
• Since half life of albumin is 20 days, decrease in albumin occurs in chronic liver
diseases.
•Albumin
• it is most abundant protein in serum [120 mg/kg/day]
• ↓albumin
• Impaired synthesis (malnutrition, malabsorption, hepatic dysfunction,
cirrhosis)
• Loss (ascites, protein losing-nephropathy, enteropathy)
• May result in peripheral oedema.

36. • In chronic liver dieases globulins increase due to decrease clearance
by hepatocytes
• IgA level increased in all types of cirrhosis
• IgG level increases in Auto-immune hepatitis and cirrhosis
• IgM elevates in biliary cirrhosis

37. • Since prothrombin is one coagulation factor synthesized by Liver,
any damage to liver can causes decrease in synthesis of
Prothrombin
• I.e Hypoprothrombinaria indicates liver dysfunction
• i.e Increased in prothrombin time
• Since PT is also prolonged in Vitamin-K Deficiency it is carefully
ruled out by estimating PT BEFORE and AFTER Vitamin-K
administration.
• PT also be prolonged in chronic obstructive Jaundice due to
resistant in Vitamin-K reabsorption (malabsorption of Vitamin-K)
• THUS PT IS USEFUL IN DIAGNOSIS OF JAUNDICE AND LIVER
FUNCTION

38. • IN ADDITION TO THESE,
• 1. CERULOPLASMIN
• 2. ANTITRYPSIN
• 3. HEPATOGLOBULIN
• 4. TRANSFERRIN is also estimated for Liver Function Studies