Download Liver function tests

Liver function tests
The liver is the largest organ in the body 
It is located below the diaphragm in the right upper quadrant of the abdominal 
cavity and extended approximately from the right 5th rib to the lower border of
the rib cage.
The liver is separated into a right and left lobe, separated by the falciform
ligament. The right is much larger than the left .
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The working cells of the liver are known as hepatocytes, which have a unique
capacity to reproduce in response to liver injury.
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Liver regeneration can occur after surgical removal of a portion of the liver or
after injuries that destroy parts of the liver.
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Although the liver's ability to react to damage and repair itself is remarkable,
repetitive insults can produce liver failure and death.
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Excretory function: bile pigments, bile salts and cholesterol are excreted in bile into
intestine.
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Metabolic function: liver actively participates in carbohydrate, lipid, protein, mineral
and vitamin metabolisms.
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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
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.
The title ‘liver function tests’ is, however, somewhat of a misnomer; only the bilirubin and
albumin given in this panel offer information regarding the functional capacity of the liver.
At a basic level
the evaluation of liver enzymes simply gives information as to whether a patient’s primary
disorder is hepatitic or cholestatic in origin.
However, much more may be interpreted from these assays with knowledge of enzyme
ratios and pattern
recognition.
LFTs alone do not give the physician full information, but used in combination with a
careful history, physical examination (particularly ultrasound .can contribute to
making an accurate diagnosis of the specific liver disorder.
Different tests will show abnormalities in response to
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liver inflammation 
liver injury due to drugs, alcohol, toxins, viruses 
Liver malfunction due to blockage of the flow of bile
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Liver cancers 
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
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.
Direct Bilirubin + Diazotized Sulfanilic Acid → Azobilirubin (Redish purple) 
♣ total bilirubin + dimethylsulfoxide(DMSO)+methanol +diazotized sulfanilic acid to
form azobilirubin.
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Indirect bilirubin react with diazotized sulfanilic acid after addition of methanol. 
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The absorbance of the reaction mixture at 555 nm is directly proportional to the
concentration of direct bilirubin.
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urine(/faeces) 
A. urobilinogen : 
Conjugated bilirubin is excreted via bile salts to intestine. Bacteria in the intestine
break down bilirubin to urobilinogen for excretion in the feces (normal value for fecal
urobilinogen = 40 - 280 mg/day)
Elevated levels of GPT may indicate :
alcoholic liver disease
cancer of the liver
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cholestasis or congestion of the bile ducts
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cirrhosis or scarring of the liver with loss of function
death of liver tissue
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Hepatitis or inflammation of the liver
noncancerous tumor of the liver
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use of medicines or drugs toxic to the liver 
GOT also reflects damage to the hepatic cells and is less specific for liver disease. It
can also be released with heart, muscle and brain disorders.
Therefore, this test may be ordered to help diagnose various heart, muscle or
brain disorders, such as a myocardial infarct (heart attack).
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This test measures the total level of the enzyme lactic dehydrogenase, also called LDH, in the
blood. LDH is found in body tissues and organs