Function of Liver

1.Metabolic Functions:
 Urea cycle
 Glycogen synthesis
 Vitamin Metabolism
 Minral Metabolism
 Lipid Metabolism
 Glycolysis
2.Excretory Functions:
 Cholesterol
 Bile Pigments
 Bile salts
3.Protective Functions & detoxification:
 Ammonia
 Clearance of insulin, PTH, estrogens, cortisol.
4.Hematological function:
 Formation of Blood
 Destruction of erythrocytes
5. Synthetic functions:
 Protein, Albumin, Prothrombin, Hormones
6.Storage Functions:
 Glycogen, Vitamin A, D and B12
USES
 Screening of liver dysfunction
 To recognize Pattern of liver disease
 To Assess Prognosis of patient
 Follow up of disease
 To evaluate the response to therapy
Liver function tests include:
 SGPT (ALT-Alkaline Transaminase)
 SGOT (AST-Aspartate Transaminase)
 GGT (Gama glutamic traspeptidase)
 ALP (Alkaline Phosphatase)
 Bilirubin
 Total Protein
 Serum Albumin
 Serum Globulin
 PT/BT /CT (Prothombin, Bledding, Clotting
Time)
 5’ nucleotide
Other test include:
 Blood ammonia
 LDH (Lactate Dehydrate)
 AFP (Alfa feto protein)
 Ceruloplasmin
 Leucine aminopeptidase
 Alpha - 1 antitrypsin
 Procollagen III peptide
 Cholesterol
 Glycoprotein
 SGPT(ALT)
 Method: L- Alanine LDH UV Kinetic (IFCC
kinetic)
 Measuring the rate of decrease in absorbance of
NADH at 340 nm due to the oxidation of NADH to
NAD.
Pyruvate+NADH+H+ Ldh Lactate +NAD+
Significance
• Serum Glutamic Pyruvate Transaminase (SGPT)
• Alanine aminotransferase (ALT)
• Enzyme present in hepatocytes .
• Significantly elevated levels of ALT (SGPT) often
suggest the existence of other medical problems such
as viral hepatitis, diabetes, congestive heart failure,
liver damage, bile duct problems, infectious
mononucleosis, or myopathy.
• So ALT is commonly used as a way of screening for
liver problems.
INERFARANCE:
 Alanine transaminase (ALT) – 10-40 u/L
• When a cell is damaged, it leaks this enzyme into the
blood, where it is measured.
• ALT rises in
– Viral hepatitis
– Alcoholic Liver disease
– Hepatic congestion
– Hepatocellular carcinoma
– Cholecystitis
– Paracetamol (acetaminophen) overdose.
SGOT (AST) Principal
 Method: L- Alanine LDH UV Kinetic
 SGOT (AST) catalyzes the transfer of amino group
between L-Aspartate and α Ketoglutarate to form
Oxaloacetate and Glutamate.
 The Oxaloacetate formed reacts with NADH in the
presence of Malate Dehydrogenase to form NAD.
 The rate of oxidation of NADH to NAD is measured as
a decrease in absorbance which is proportional to the
SGOT (AST) activity in the sample.
L-Aspartate + α Ketoglutarate SGOT Oxaloacetate + L-Glutamate
Significance
 Serum Glutamic Oxaloacetic Transaminase (SGOT)
 The AST is a cellular enzyme is found in highes concentration
in heart muscle, The cells of the liver the cells of the skeletal
muscle & in smaller amounts in other weaves.
 The blood SGOT levels are thus elevated with liver damage
or insult to the heart.
Some medication can also raise SGOT level.
Interference
• Normal Range:- 10-40 U/L
• It is raised in acute liver damage,
• But,also present
– Red blood cells
– Cardiac and Skeletal muscle
– And therefore it is not specific to the liver.
GGT PRINCIPAL
 Method: Carboxy Substrate Method
 GGT catalyzes the transfer of amino group between L-
γ-Glutamyl-3-carboxy-4 nitroanilide and Glycylglycine
to form L- γ-Glutamylglycylglycine and 5-amino-2-
nitrobenzoate.
 The rate of formation of 5-amino-2-nitrobenzoate is
measured as an increase in absorbance which is
proportional to the GGT acitivity in the sample.
L- γ-Glutamyl 3-carboxy 4-nitroanilide + Glycylglycine
GGT L- γ-Glutamyl glycylglycine+ 5-Amino-2-
nitrobenzoate.
Significance
 The gamma-glutamyl transferase (GGT) test may be
used to determine the cause of elevated alkaline
phosphatase (ALP).
 Both ALP and GGT are elevated in disease of the bile
ducts and in some liver diseases.
Interference
• Normal Range: 10-30 u/L.
 Although reasonably specific to the liver and a more
sensitive marker for cholestatic damage than ALP.
• Gamma glutamyl transpeptidase (GGT) may be elevated
with even minor, sub-clinical levels of liver dysfunction.
• GGT is raised in alcohol toxicity (acute and chronic).
ALP PRINCIPAL
 Method: para-nitrophenylphosphate with AMP
buffer
 Alkaline phosphatase in the sample catalyzes the
hydrolysis of colourless p-nitrophenyl phosphate
(p-NPP) to give p-nitrophenol and inorganic
phosphate.
 At the pH of the of the assay (alkaline), the p-
nitrophenol is in the yellow phenoxide form.
 The rate of absorbance increase at 404 nm is
directly proportional to the alkaline phosphatase
activity in the sample.
 Optimized concentrations of zinc and magnesium
ions are present to activate the ALP in the sample.
Reaction:
CLINICAL SIGNIFICANCE
 Increased levels of serum ALP;
In growing children
Bone disease like;
Metastasis, rickets, healing fractures, Osteomalacia.

Sex Age Reference Interval

Male-femals 4-15 yr 54-36 U/L
Male 20-50 yr 53-128 U/L
Male >60 yr 56-119 U/L
femals 20-50 yr 42-98 U/L
femals >60 yr 53-141 U/L
Interference
• Mild elevations (<500 IU/L)
– Viral hepatitis
– Alcoholic cirrhosis
– Infiltrative liver disease like lymphoma, sarcoidosis
• Moderate elevation (500 – 1000 IU/L)
– Cholecystitic
– Gall bladder stone
• Severely elevation (>1500 IU/L)
– Osteomalacia
– Osteoporosis
– Ricket
– Osteosarcoma
– Bone tumour
– Paget's disease
Bilirubin PRINCIPAL

 Method: Diazo Reaction

 Bilirubin glucuronide +diazonium salt azodye

(tan or pink to viotel)
Different between Unconjugated &
Conjugated Bilirubin
UNCONJUGATED CONJUGATED
In water Insoluble Soluble
In alcohol Soluble Soluble
Normal <1.3 <0.4
In bile Absent Present
In Urine Always absent Normally absent
Absorption gut Absorbed Not absorbed
Diffusion into Diffuses-yellow Doesn’t diffuse
tissues colour
Van den bergh Indirect + Direct +
Bilirubin Pathway
Type & Cause of Jaundice
 Pre-hepatic Jaundice  Intra-Hepatic Jaundice
 Neonatal  Acute Viral hepatitis
(Physiological) Jaundice  Alcohol Cirrhosis
 Malaria  Cirrhosis of Liver
 G 6 PD deficiency  Primray Biliary Cirrhosis,
 Thalassaemia  Haemochromatosis
 Sickle cell disease  Wilson Disease
 Mis-match Blood  Alpha-1 antitrypsin deficiency
Transfusion  Drug induce – Quinine Group,
 Auto-immune NSAID, Chemotherapeutic drugs
 Post Hepatic Jaundice
 Gall Bladder - Common Bile Duct - Pancreatic duct Stone
 Gall Bladder - Hepatic – Pancreatic – Duodenal Carcinoma
OBSTRUCTIVE JAUNDICE
PHYSIOLOGIC JAUNDICE OF THE
NEWBORN
PHOTOTHERAPY
 Heamolytic Obstructive
r
Blood Examination
Total Billirubin ↑↑ ↑↑ ↑↑
Direct Billirubin Normal ↑ ↑↑
direct Billirubin ↑↑ ↑ Normal
ALT Normal ↑↑ Normal
Alkaline
Normal Normal / ↑ ↑↑
phosphatase
Urine Examination
Bile Pigment Normal Normal / ↑ ↑↑
Urobillinogen ↑↑ Normal / Absent Absent
Bile Salt Normal Normal / ↑ ↑↑

ool Examination Normal Normal Clay Colour

Specific 31
Haemoglobin, LDH Liver Function Test USG Abdomen
Van den bergh Test :Direct &
Indirect Bilirubin
 Method: Diazo Reaction
 This is specific reaction to identify the increase in
serum bilirubin level.
 Normal serum gives a negative Van den Bergh
reaction.
 sulfanilic acid + sodium nitrate Diazotized
 Diazotized sulfanilic acid + bilirubin Azobilirubin
(purple color).
Give major causes for increase in
blood Bilirubin level:-
 Major causes for increase bilirubin levels in blood:
 Hemolysis:-
Damage to RBC may cause increased breakdown
of Hb producing Unconjugated Bilirubin, which may
overload liver conjugating system, causing
Hyperbilirubinemia;
 Failure of Conjugating system in the liver,
 Obstruction in the Biliary system,
Total Protein PRINCIPAL
 Method: Biuret
 Proteins react with cupric ions in alkaline medium to
form a violet colored complex. The intensity of the
color produced is directly proportional to proteins
present in the specimen and can be measured on a
photometer at 530 nm (or by using a green filter).
Normal Range
Serum Protein: 6-8 g/dl
Albumin Principal
 Method: Bromocresol Green (BCG)
 Albumin present in serum binds specifically with
bromocresol green at pH 4.1 to form green colored
complex, intensity of which can be measured
colorimetrically by using 640 nm (or a red filter)
Normal Range
3.3-4.8 g/dl
Total Protein & Albumin
• Both decrease in Hepato-cellular disease.
• Because it is synthesized & store into liver.
• It may found decrease in following disease:
• Malnutrition
• Chronic disease
• Nephrotic syndrome
• Inflammatory bowel disease
• Chronic infection
• Tuberculosis
Prothombin time Principal
 Method: Capillary tube method
 When preformed tissue thromboplastin and calcium
chloride are added to citrated plasma, the plasma
clots.
 The time taken for the clot to appear is called
Prothrombin time (PT).
Significance
 Prothrombin time (PT) is a blood test that measures
how long it takes blood to clot.
 A prothrombin time test can be used to check for
bleeding problems.
 PT is also used to check whether medicine to prevent
blood clots is working. A PT test may also be called an
INR test.
Normal Range
11 to 16 second
Interferance
• Another measure of hepatic synthetic function is the
prothrombin time.
• Prothrombin time is affected by proteins synthesized by the
liver.
• Thus, in patients who have prolonged prothrombin times, liver
disease may be present.
• Since a prolonged PT is not a specific test for liver disease,
confirmation of other abnormal liver tests is essential.
• Diseases such as malnutrition, in which decreased vitamin
K ingestion is present, may result in a prolonged PT time.
• An indirect test of hepatic synthetic function includes
administration of vitamin K (10mg) subcutaneously over
three days.
• Several days later, the prothrombin time may be
measured. If the prothrombin time becomes normal, then
hepatic synthetic function is intact.
• This test does not indicate that there is no liver disease,
but is suggestive that malnutrition may coexist with (or
without) liver disease.
Bledding Time
 Determination of bleeding time helps to detect
vascular defect & platelet disorder.
 Prolonged bleeding time is generally absociated
thrombocytopenia.
Principle:- A 1mm deep prick made on ear lobe or finger
of the patient the length of time required for bleeding
to cease is record.
Normal Range:- 1-5 minutes
Procedure
 Sterilize the finger lip or ear lobe with spirit and given
a deep prick to get free flow of blood, immediately,
with a clean, white filter paper and note the time.
Continue to apply the filter paper to pricked site at the
interval 30 seconds, till no blood stain is seen on the
filter paper. The duration of time from the firs sport till
no blood stain on filter paper is known as BLEEDING
TIME.
Clotting Time
Principle:- Blood is collected in capillary tube after a
finger prick & the stop watch is started. The formation
of fibrin string is noted by breaking the capillary tube
at regular interval, The time is noted at the first
appearance of the fibrin string.
 This method is generally useful in severe clotting
disorders.
 Normal Range:- 4-9 min.
Procedure
 Sterilize the finger top with spirit and given a deep
prick to get free flow of blood. Start the stop watch as
soon as blood starts coming out. Fill a thin capillary
tube (it will be filled by capillary action by just
applying the tip on the blood drop) with blood. After
every 30 seconds, break a small portion of the capillary
tube till a thin line of unbroken coagulam is seen
between the broken ends. Stop the stop watch and
note the time. This is CLOTTING TIME.
Blood Ammonia
 Ammonia is a by product of amino acid catabolism.
 Ammonia is used as a potential marker of hepatic
encephaophathy, but it is not a good test for liver
function.
 High annonia levels have been found with near normal
liver function and vice versa.
Roll of liver
 Liver converts blood ammonia into urea and muscles use it
in transmination reaction to produce glutamate or alanine
etc..
 Pateints with advanced liver diseases usually also have
muscle wasting which then also contributes, to
hyperammonemia.
 Liver biopsy is oftern the last test used to arrive at a final
diagnosis of liver disease.
 It is indicated in chronic cases of liver diseases
characterized by unexplained clinical findings pointing to
liver disease.
Coagulation tests
• The liver is responsible for the production of coagulation
factors.
• If it is increased, it means it is taking longer than usual
for blood to clot.
• It will only be increased if the liver is so damaged that
synthesis of vitamin K-dependent coagulation factors has
been impaired.
• It is not a sensitive measure of liver function.
Hepatic neoplasm markers
 Alpha fetoprotein (AFP): primary hepatocellular
carcinoma
 Carcinoembryonic antigen (CEA): increased CEA:
liver metastatic carcinoma or other carcinomas of the
gastrointestinal system
 Abnormal prothrombin (APT): increased APT
primary hepatocellular carcinoma