This document discusses various biomarkers used in the diagnosis of liver disease. It describes how bile salts facilitate fat absorption and are excreted in urine during cholestasis. Primary and secondary bile salts are produced in the liver and intestines. Increased renal excretion of bile salts occurs during cholestasis. Liver enzymes like ALT, AST, ALP, GGT and 5-nucleotidase reflect hepatocyte damage and cholestasis. Elevated ALT and AST indicate hepatocellular injury. Increased ALP, GGT and 5-nucleotidase suggest cholestasis. Prothrombin time is prolonged in liver dysfunction due to decreased synthesis of clotting factors. Albumin and globulin

1. By
Dr KHALED ALGARIRI
CAMS- QASSIM UNIVERSITY
April 2023

2. BILE SALTS
 Products of cholesterol metabolism
 Facilitate absorption of fat from intestine
 Constitute a substantial amount of bile in bilirubin
 excretion and can be used in diagnosing cholestasis
 Primary bile salts – cholate and chenodeoxycholate are produced in liver
 Metabolised by bacteria in intestine
 Produces secondary bile salts – lithocholate, deoxycholate and
ursodeoxycholate

3.  In normal condition – renal excretion of bile salts is negligible
 In cholestasis – increased renal excretion of bile salts
 For measuremnet – chromatography (HPLC)
 Hay’s test – bile salts when present lower the surface tension of
urine
 When sulphur powder is added to the urine, sulphur particles
sink to the bottom of the tube
 In case of normal urine, it will float on the surface

4. ENZYMES IN DIAGNOSIS OF LIVER DISEASE

5. SERUM ENZYMES REFLECT THE DAMAGE OF
HEPATOCYTES
A large number of enzyme estimations are available which
are used to as certain liver function.
They are be divided into two groups:
A). Enzymes indicating hepatocellular damage.
B). Enzymes indicating cholestasis (obstruction).
In liver cells injury , damage to the membrane of cells &
organelles allows intracellular enzymes to leak into the
blood

6. A- Enzymes indicating hepatocellular damage
 AST (Aspartate transaminase)/SGOT (serum
glutamate oxaloacetate transaminase)
Normal range: 10-45 U/L.
 AST is found in both cytoplasm & mitochondria
 AST also reflects damage to the hepatic cells & is less
specific for liver disease.
AST help diagnose various heart, muscle or brain
disorders, such as a myocardial infarct (heart attack).

7. Alanine transaminase ALT sGPT
Normal Range: 5-40 U/L.
 ALT(SGPT) – found primarily in liver .
ALT is specific for liver disease.
Its elevations favor liver cell necrosis as a cholestasis.

8. Serum aminotransferases (AST-ALT) are the sensitive
markers of acute hepatocellular injury.
Serum alanine aminotransferase or ALT (formerly called
serum glutamic-pyruvic transaminase or SGPT) is a cytosolic
enzyme.
When necrosis or death of cells containing these enzymes
occurs, aminotransferases are released into the blood and
their concentration in blood increases whose level
correlates with extent of tissue damage.

9. Most marked elevations of ALT and AST (>15 times normal)
are seen in acute viral hepatitis, toxin-induced
hepatocellular damage (e.g. carbon tetrachloride), and
centrilobular necrosis due to ischemia (congestive cardiac
failure).
Moderate elevations (5-15 times) occur in chronic hepatitis,
autoimmune hepatitis, alcoholic hepatitis, acute biliary tract
obstruction, and drug-induced hepatitis.
Mild elevations (1-3 times) are seen in cirrhosis,
nonalcoholic steatosis, and cholestasis.
Clinical Significant of Transaminase
Enzymes

10. Clinical Significant of Transaminase Enzymes
Increase of AST and ALT is much more in hepatocellular jaundice
(>500 units/ml) than in cholestatic jaundice (<200 units/ml).
ALT and AST are elevated in acute viral hepatitis even before the
appearance of jaundice.
Persistence of elevated ALT and AST beyond 6 months in a case
of hepatitis indicates development of chronic hepatitis
Normal ALT:AST ratio is 0.7 to 1.4.

11. ELEVATION OF SERUM ALT MAY INDICATE
Alcoholic liver disease
Cancer of liver
Hepatitis or inflammation of the liver
Noncancerous tumor of the liver
Use of medicines or drugs toxic to the liver
Cirrhosis or scarring of the liver
Death of liver tissue.

12. AST:ALT ratio
Normal ratio is 0.7 to 1.4
Useful in Wilson disease, chronic liver disease and alcoholic
liver disease
 AST/ALT ratio > 3:1 is highly suggestive of Alcoholic liver disease
AST in Alcoholic liver disease is rarely >300 IU/L.
 ALT is usually normal in alcoholic liver disease ; can be
sometimes low due to an alcohol induced deficiency of pyridoxal
phosphate
 AST/ALT <1 is seen in viral hepatitis.

13. Clinical Significant of serum AST/ALT ratio

14. B- ENZYMES THAT DETECT CHOLESTASIS
1. ALKALINE PHOSPHATASE
2. Gamma-GLUTAMYL TRANSPEPTIDASE
3. 5-NUCLEOTIDASE

15. 1-ALKALINE PHOSPHOTASE
ALP occurs in in all tissues, especially liver, bone, bile duct, kidney & the
placenta.
The ALP used to help diagnose certain liver diseases and bone disorders.
Normal range: 30 - 95 IU/L
ALP is a hydrolase enzyme responsible for removing phosphate groups from
many types of molecules, including nucleotides & proteins.
Levels are significantly higher in growing children.
A rise in serum ALP usually associated with elevated serum bilirubin is an
indicator of biliary obstruction (obstructive/post hepatic jaundice).
ALP is also elevated in cirrhosis of liver & hepatic tumors.

16. Physiological increase in ALP is seen in –
1. >60 yrs
2. Pregnancy
3. Blood groups O and B – after fatty meal influx of intestinal ALP into blood
4. In children and adolescent during rapid bone growth
If an isolated increase in ALP is seen , identification of the source of
elevated isoenzyme is helpful- by fractionation of ALP by electrophoresis.
Measure serum levels of GGT and 5’NT – they are elevated in only liver
disease

17. Isoenzymes of Alkaline Phosphatase
1.Hepatic Isoenzyme – Travels fastest towards the anode .Its
level rises in extra hepatic biliary obstruction.
2. Bone Isoenzyme-Increases due to osteoblastic activity and is
normally elevated in children during periods of active growth .
3. Placental Isoenzyme - Rises during last 6 weeks of pregnancy.
4. Intestinal Isoenzyme- Rise occurs after a fatty meal. May
increase during various GI disorders.

18. Clinical Significant of ALP
Normal range Adult: 42.0-128.0 IU/L. Children: 82.0-
390 IU/L
In acute viral hepatitis, alkaline phosphatase is usually either
normal or moderately increased. Hepatitis A may present a
cholestatic picture with marked and prolonged itching and
elevation of alkaline phosphatase. Tumour may secrete alkaline
phosphatase into plasma and there are tumour specific
isoenzymes such as Regan, Nagao and Kasahara isoenzymes.

19. Clinical Significant of ALP
 Hepatic and bony metastasis can also cause elevated levels of
alkaline phosphatase. Other diseases like infiltrative liver
disease, abscesses, granulomatous liver disease and
amyloidosis may also cause a rise in alkaline phosphatase.
Mildly elevated levels of alkaline phosphatase may be seen in
cirrhosis and hepatitis of congestive cardiac failure.
 Low levels of alkaline phosphatase occur in hypothyroidism,
pernicious anemia, zinc deficiency and congenital
hypophosphatasia.

20. Enzymes Prehepatic
Jaundice
Hepatic
Jaundice
Obstructive
Jaundice
ALS or ALT Normal Marked
Elevation
Elevation
ALP Normal Slightly
increase
Marked
Elevation
Enzyme assays in differential
diagnosis of Jaundice

21. Abbreviations: GGT, γ-glutamyltranspeptidase; L-AP, liver-specific alkaline
phosphatase; B-AP, bone-specific alkaline phosphatase; 5′nT, 5′- nucleotidase;
HFP, hepatic function panel; THP, transient hyper-alkaline phosphatemia; Ca/P,
calcium/phosphorus; PTH, parathyroid hormone

22. Gamma Glutamyl transpeptidase(GGT) is a membrane bound glycoprotein
which catalyzes the transfer of gamma glutamyl group to other peptides,
amino acids and water.
Large amounts are found in the kidneys, pancreas, liver, intestine and
prostate.
 The levels of gamma glutamyl transpeptidase are high in neonates and
infants up to 1 year and also increase after 60 years of life. Men have higher
values. Children more than 4 yr old have serum values of normal adults.
The normal range is 0-30 IU/L.
In acute viral hepatitis the levels of g glutamyl transpeptidase may reach its
peak in the second or third week of illness and in some patients they
remain elevated for 6 weeks.
2- Gamma GLUTAMYL TRANSPEPTIDASE GGT

23. Clinical Significant of GGT
Often clinicians are faced with a dilemma when they see
elevated alkaline phosphatase levels and are unable to
differentiate between liver diseases and bony disorders and in
such situations measurement of gamma glutamyl transferase
helps as it is raised only in cholestatic disorders and not in
bone diseases.
Other conditions causing elevated levels of Gamma glutamyl
transpeptidase include diabetes mellitus, acute pancreatitis and
myocardial infarction. Drugs may increase the levels of Gamma
glutamyl transpeptidase..

24. Clinical Significant of GGT
The enzyme present in serum appears to originate primarily from
the Hepatobiliary system.
GGT activity is elevated in all forms of liver disease like
1. Obstructive jaundice
2. Cholangitis
3. Cholecystitis
4. Biliary atresia
5. Infectious hepatitis

25. Clinical Significant of GGT
Relatively high sensitivity and specificity because of their
measurement is easy and in expensive.
 Elevated earlier in liver diseases.
 Early detection of chronic alcohol misuse.
Enzyme level found correlate with the duration of the drug
action.

26. 3- 5'-Nucleotidase
Normal range: 2-15 U/L
 The serum activity of 5'-nucleotidase is elevated
in hepatobiliary disease & this parallels ALP.
 It is highest in post-hepatic obstructive jaundice.
The 5'-nucleotidase is normal in patients with bone
disease where as serum ALP increased.
 GGT and 5’NT is especially used to assess the nature of
ALP.

27. TESTS BASED ON SYNTHETIC
FUNCTION
Prothrombin
time
Protein
time

28. SYNTHETIC FUNCTION OF LIVER
Liver is involved in synthesis of many plasma proteins like BLOOD CLOTTING
FACTORS, LIPO PROTEINS, ETC..
• SYNTHESIS of these compounds may be affected in pathological conditions of
liver..
• i..e their concentration in plasma may decrease, however of their long HALF
LIIFE and REGENARATION capacity of liver decrease may be apparent only on
long standing liver diseases
• THESE INCLUDE
1. Serum Albumin
2. Prothrombin
3. Serum Glubins

29. 1-Serum Albumin
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]
• Reduction of albumin occurs in Impaired synthesis
(malnutrition, malabsorption, hepatic dysfunction,cirrhosis)
1. Loss (ascites, protein losing-nephropathy, enteropathy)
2. May result in peripheral oedema.

30.  Due to its slow turn over – not a good indicator of acute or mild hepatic
dysfunction
 • In hepatitis - <3g/dl of albumin – possibility of chronic liver disease
•Non hepatic causes of Hypoalbuminemia -
1. Protein losing enteropathy
2. Nephrotic syndrome

31. 2-Serum Globulins
 In chronic liver diseases 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

32. 3-Prothrombin Time PT
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.

33. 3-Prothrombin Time PT
Vitamin K helps to make various proteins that are needed for
blood clotting and the building of bones. Prothrombin is a
vitamin K-dependent protein directly involved with blood
clotting. Osteocalcin is another protein that requires vitamin K to
produce healthy bone tissue.
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

34. Normal value : 10 to 15 sec.

35. TESTS BASED ON
DETOXIFICATION FUNCTION
Hippuric acid
test
Determination
of blood
ammonia

37. Hippuric acid test
Hippuric acid test
• 6gm of sodium
benzoate dissolved in 250ml water
• Collect urine for next 4 hour
Hippuric acid is a normal component of urine and is typically
increased with increased consumption of phenolic compounds
(tea, fruit juices). These phenols are converted into benzoic acid
which is then converted into hippuric acid and excreted in the
urine.

38. THANK YOU