Liver Function Test
Understanding Liver
Function & Health
With Liver Function
Tests
Liver function tests (LFTs) are a
group of blood tests that provide detailed information about the overall health
and functioning of the liver. Liver plays a critical role in a number of body
processes including metabolism, detoxification, protein synthesis, and several
other notable functions. Liver function tests play an important role in
diagnosis and monitoring of liver diseases or severe conditions that affect
liver health and functioning. Abnormal results of the components of the liver
function tests may often times indicate liver diseases but further confirmatory
testing are always needed to ensure the right diagnosis.
Components of Liver Function Tests:
Alanine Aminotransferase (ALT or SGPT):
Alanine Aminotransferase is an
enzyme present in the liver. Elevated levels of ALT often indicate liver damage
which might be associated with conditions that affect liver health such as
hepatitis or liver injury due to certain medications or other conditions such
as nonalcoholic fatty liver disease or liver cirrhosis. Normal range of ALT is
7-56 units per liter (U/L).
Aspartate Aminotransferase (AST or SGOT):
Aspartate Aminotransferase is an
enzyme found in sufficient quantity in liver, heart, muscles, and other organs.
Elevated levels of AST, similar to ALT levels, are indicative of liver damage
or injury. However, AST levels are also elevated in certain heart or muscle
damage conditions. Normal ranges of AST are 10-40 U/L.
Alkaline Phosphatase (ALP):
Alkaline phosphatase is an enzyme
majorly found in liver, bile ducts, placenta, and bones. Elevated levels of
alkaline phosphatase can indicate liver or bile ducts disease, bone disorders.
However, high levels of alkaline phosphatase can be an indication of normal
growth in children and teens. Additional testing is often required to determine
the underlying cause of high levels of alkaline phosphatase. Normal range of
ALP is 44-147 U/L.
Gamma-Glutamyl Transferase (GGT):
Gamma-glutamyl transerase is an
active enzyme found in liver, bile ducts, and pancreas. Elevated levels of GGT
are often an indication of liver or bile duct injury or disease, excess alcohol
consumption, and certain medications. Normal range of GGT is 9-48 U/L.
Total Bilirubin:
Bilirubin is majorly formed from
the breakdown of red blood cells (RBCs). Various reasons of elevated bilirubin
levels can include liver injury or disease, haemolytic anemia, bile duct
obstruction, or Gilbert’s syndrome. In addition, elevated levels of this yellow
pigment can indicate excessive red blood cell breakdown. Normal range of total
bilirubin is 0.3-1.0 mg/dL.
Direct Bilirubin:
Direct bilirubin is a form of
bilirubin that is a conjugated with glucoronic acid and is excreted in the
bile. The measurement of this form of bilirubin helps in monitoring and
diagnosis of many diseases that are associated with raised bilirubin.
Albumin:
Albumin is a protein made by
liver that helps in maintaining blood volume and pressure. Low levels of
albumin can indicate liver damage or diseases, kidney disorders, or
malnutrition. Normal range of albumin is 3.4-5.4 mg/dL.
Total Protein:
Total protein measurement is the
total amount of proteins - albumin and globulins - present in the blood.
Abnormal levels of total protein can be indicative of liver disease, kidney
problems, or certain immune disorders. Normal range of total protein is 6-8.3
mg/dL.
Prothrombin Time (PT) and International Normalised Ratio (INR):
PT and INR are markers of the time taken by the blood to clot. Since liver produces blood clotting factors, abnormal levels of these two metabolites can indicate liver disease or issues with blood clotting. The normal ratio is in the range of 0.9-1.2.
Procedure:
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Patients may be asked to fast for 9-12 hours before the
test to get accurate results.
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A trained healthcare professional such as a
phlebotomist will prepare patient’s arm for the venipuncture.
●
A tourniquet is tied to the arm and the area to be
punctured is cleaned with an antiseptic or rubbing alcohol to make it sterile.
●
A needle is then inserted into the vein in the arm of
the patient and blood is drawn into tubes lined with anticoagulants to prevent
damage to the blood sample.
●
The tourniquet is removed and a cotton swab is placed
to stop the bleeding.
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The sample is then sent to the laboratory for analysis
wherein automated equipment is used to measure the levels of various markers
such as ALT, AST, ALP bilirubin, albumin, GGT, PT/INR, among others.
●
The results are then interpreted by the healthcare
professionals and discussed with the patient to determine the appropriate
treatment options.
Reasons to Get a Liver Function Test Done:
●
Timely diagnosis of potential liver diseases or
disorders
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For patients with chronic liver disease, LFTs are
essential for monitoring disease progression and treatment response
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Timely evaluation of liver injury caused by drugs,
alcohol, toxins, or infections
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Provides accurate assessment of overall health and well-being
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Plays an important role in preoperative assessment
