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LIVER FUNCTION TESTS
WHAT IS LIVER FUNCTION TEST?
 
Most liver disease cause only mild symptoms initially, but it is vital that these diseases be detected early. Hepatic (liver) involvement in some diseases can be of crucial importance. Because liver cancer often develops in damaged livers, doctors need to know the condition of your liver before starting your treatment. A series of blood tests can help with this. These tests can assess the condition of the part of your liver not affected by the cancer. They measure levels of certain substances in your blood, such as bilirubin, albumin, alkaline phosphatase, AST, ALT, and GGT. You may not be able to have curative surgery if your liver is not healthy, as the surgery might require the doctor to remove a good part of your liver. This is a common problem in people with liver cancer. Blood testing is necessary so that the doctor has all pertinent information and can then weigh treatment options.
Liver Function Test (LFT) is the initial step in detecting liver damage. It is performed by a medical technologist on a patient's serum or plasma sample obtained by phlebotomy. LFTs is an important test to determine the presence of certain liver enzymes in the blood. Among the most sensitive and widely used liver enzymes are the aminotransferases. They include aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). These enzymes are normally contained within liver cells. If the liver is injured, the liver cells spill the enzymes into blood, raising the enzyme levels in the blood and signaling the liver damage. Normal or reference values for LFTs can vary among laboratories due to the age or gender of the patient, as well as the laboratory method used for testing.
LIVER ENZYMES
ALT or SGPT
Alanine aminotransferase (ALT) or Serum glutamic pyruvic transminase (SGPT) is an enzyme primarily found in the hepatocytes (liver cells), making it a more specific test for detecting liver abnormalities.
When a cell is damaged, it leaks this enzyme into the blood, where it is measured. ALT rises dramatically in acute liver damage, such as viral hepatitis or paracetamol (acetaminophen) overdose.
Why It Is Done
The ALT test is done to:
- Find out whether jaundice was caused by a blood disorder or liver disease.
- Help check for liver damage.
- Identify liver disease, especially cirrhosis and hepatitis caused by alcohol, drugs, or viruses.
- Keep track of the effects of cholesterol-lowering medicines and other medicines that can damage
the liver.
* ALT (SGPT) normal range is 5-35 IU/L.
AST or SGOT
Aspartate aminotransferase (AST) or Serum glutamic oxloacetic transminase (SGOT) is similar to ALT in that it is another enzyme associated with liver parenchymal cells. AST or SGOT is not only found in the liver. It is also normally found in heart, muscle, brain, and kidney tissue. Injury to any of these tissues can cause an elevated blood level. The ratio of AST to ALT is sometimes useful in differentiating between causes of liver damage. Elevated AST levels are not specific for liver damage and AST has also been used as a cardiac marker.
Why it is done
An AST test is done to:
- Check for liver damage.
- Check on the success of treatment for liver disease.
- Find out whether jaundice was caused by a blood disorder or liver disease.
- Help identify liver disease, especially hepatitis and cirrhosis. Liver disease may produce symptoms
such as pain in the upper abdomen, nausea, vomiting, and sometimes jaundice.
- Keep track of the effects of cholesterol-lowering medicines and other medicines that can damage
the liver.
* AST (SGOT) normal range is 10-34 IU/L.
ALP
Alkaline phosphatase (ALP) is an enzyme in the cells which line the biliary ducts of the liver. ALP levels in plasma will rise with large bile duct obstruction, intrahepatic cholestasis or infiltrative diseases of the liver. ALP is also found in other organs including bone, placenta, and intestine.
When ALP is elevated, another test known as GGT (gamma-glutamyl transferase) can be ordered by the doctor to confirm that the elevated ALP is being derived from the liver or biliary tract.
Why it is done
A test for alkaline phosphatase (ALP) is done to:
- Check bone problems (sometimes found on X-rays), such as rickets, osteomalacia, bone tumors,
Paget's disease, or too much of the hormone that controls bone growth (parathyroid hormone). The
ALP level can be used to check how well treatment for Paget's disease is working.
- Check for liver disease or damage to the liver. Symptoms of liver disease can include jaundice,
belly pain, nausea, and vomiting. An ALP test may also be used to check the liver when medicines
that can damage the liver are taken.
* ALP normal range: 20-140 IU/L
GGTP or GGT
Gamma-glutamyl transpeptidase (GGPT) or Gamma-glutamyl transferase (GGT) is an enzyme which is useful clinically when compared to ALP. Gamma glutamyl transpeptidase (GGT) may be elevated with even minor, sub-clinical levels of liver dysfunction. It can also be helpful in identifying the cause of an isolated elevation in ALP. GGT is raised in alcohol toxicity (acute and chronic). By comparing the two, it can be determined if the patient has bone or liver disease. GGT or GGTP
Why it is done
A blood test to measure GGT levels is done to check for liver damage, especially damage caused by alcohol abuse. A GGT test is usually done along with other tests (such as alanine aminotransferase, or ALT) because it cannot usually tell what disease is causing the liver damage.
This test is used to detect diseases of the liver or bile ducts. It is also done along with other tests, such as the ALP test, to tell the difference between liver or bile duct disorders and bone disease.
Alkaline phosphatase (ALP) is increased in liver and bile duct disease as well as in bone disease. GGT is only increased in liver and bile duct disease, but not in bone disease. So, a patient with an elevated ALP and a normal GGT probably has bone disease, not liver or bile ducts disease.
* GGPT or GGT normal range: 0-51 IU/L.
OTHER LIVER FUNCTION TESTS
Alpha-fetoprotein (AFP) Blood Test
AFP is a protein and is useful in determining if a liver mass might be cancer, although it is not accurate in every case. It can also be useful in people diagnosed with liver cancer. The AFP level can help guide what treatment options might be appropriate. The test can also be used to help give an idea of how effective treatment is, as the AFP level should fall after treatment. It can be used after treatment as well, to look for possible signs that the cancer may have come back (recurred).
Angiography
Angiography is an x-ray procedure for looking at blood vessels. Angiography can be useful in showing the arteries that supply blood to a liver cancer. This can help surgeons decide whether a cancer can be removed and if so, it can help in planning the operation.
Viral Hepatitis Tests
If liver cancer has not yet been diagnosed, your doctor may also order other blood tests, such as tests for hepatitis B and C. Results showing you have been infected with either of these viruses may make it more likely that liver cancer is present.
Biilirubin
Bilirubin is produced from the breakdown of hemoglobin (the oxygen- carrying protein pigment) in red blood cells. The liver clears bilirubin from the body by excreting it through bile into the intestine. Elevated bilirubin levels causes jaundice, a yellowing of the eyes and skin, an indicative of liver disorders or blockage of bile ducts.
In laboratory tests, bilirubin is measured as total bilirubin and direct bilirubin. Total bilirubin, as it's name suggests, is a measurement of all of the bilirubin in the blood. Increased total bilirubin causes jaundice and can signal a number of problems.
Why It Is Done
The bilirubin test is used to:
- Check liver function and watch for signs of liver disease, such as hepatitis, cirrhosis or the effects
of medicines that can damage the liver.
- Diagnose conditions that cause increased destruction of red blood cells, such as hemolytic anemia
or hemolytic disease of the newborn.
- Find out if something is blocking the bile ducts. This may occur if gallstones, tumors of the
pancreas, or other conditions are present.
- Help make decisions about whether newborn babies with neonatal jaundice need treatment. These
babies may need treatment with special lights, called phototherapy. In rare cases, blood
transfusions may be needed.
* Direct Bilirubin normal range: 0-0.3 mg/dl
* Total Bilirubin normal range: 0.3-1.9 mg/dl
Albumin (ALB)
Albumin is the main protein made by the liver and it circulates in the bloodstream. Albumin, a very important protein that helps keep fluid pressures in the body stable and carries many substances in the body. Albumin may decrease in chronic liver disease, particularly if the disease is getting worse, but may be decreased for other reasons such as a lack (deficiency) of protein, for example malnutrition. The ability to make albumin (and other proteins) is affected in some types of liver disorder. A low level of blood albumin occurs in some liver disorders.
This test can help determine if a patient has liver disease or kidney disease, or if the body is not absorbing enough protein.
Albumin helps move many small molecules through the blood, including bilirubin, calcium, progesterone, and medications. It plays an important role in keeping the fluid from the blood from leaking out into the tissues.
Because albumin is made by the liver, decreased serum albumin may be a sign of liver disease. It can also result from kidney disease, which allows albumin to escape into the urine. Decreased albumin may also be explained by malnutrition or a low protein diet.
* Albumin normal range: 3.4-5.4 g/dL.
Total Protein
The majority of plasma proteins (albumin and globulins) in the body are produced by the liver. Laboratory testing for total protein is a way to differentiate between normal and abnormal liver function.
This test is often done to diagnose nutritional problems, kidney disease or liver disease. If total protein is abnormal, further tests must be done to identify the specific problem.
* Total Protein normal range: 6.0-8.3 gm/dl
Prothrombin Time (Clotting Studies)
The liver also makes proteins that help blood clot when you are bleeding. A damaged liver may not make enough of these clotting factors, which could increase your risk of bleeding. Your doctor may order blood tests, such as a prothrombin time (PT), to assess this risk. The prothrombin time (PT) is a laboratory test used to evaluate normal or abnormal blood clotting. Blood clotting factors are proteins which are made by the liver. If the liver is injured or damaged, the clotting factors are not produced normally.
Prothrombin time may indicate liver disease, especially worsening chronic liver disease if the clotting ability is prolonged. Clotting is the thickening of blood, known as coagulation. Your liver has a big role in the normal clotting of blood. When your liver is damaged your blood becomes too ‘thin’ and takes longer to clot. This may lead you to bruise more easily.
Why It Is Done
Prothrombin time (PT) is measured to:
- Check for a low level of vitamin K. Vitamin K is needed to make prothrombin and other clotting
factors.
- Check for low levels of blood clotting factors. The lack of some clotting factors can cause bleeding
disorders such as hemophilia, which is passed in families (inherited).
- Check how well the liver is working. Prothrombin levels are checked along with other liver tests,
such as aspartate aminotransferase and alanine aminotransferase.
- Check to see if blood-thinning medicine, such as warfarin (Coumadin), is working. If the test is done
for this purpose, a PT may be done every day at first. When the correct dose of medicine is found,
you will not need so many tests.
- Check to see if the body is using up its clotting factors so quickly that the blood cannot clot and
bleeding does not stop. This may mean the person has disseminated intravascular coagulation
(DIC).
- Find a cause for abnormal bleeding or bruising.
* Prothrombin time normal range: 11 to 13.5 seconds.
Other tests such as liver biopsy, ultrasound scan, CT scan, MRI etc, may be needed to clarify the cause of a liver disorder and/or to monitor its progress.
LIVER BIOPSY
 
A biopsy may be performed following blood tests and X-rays if questions still exist about the nature and severity of your liver problem. During a biopsy, a small sample of tissue is removed from your liver using a thin needle. The tissue is prepared and stained in a laboratory for examination under a microscope. In most cases, the only way to be certain that liver cancer is present is to take a biopsy but in some cases, if imaging studies (CT or MRI) show a tumor mass in the liver that is likely cancerous and a blood test reveals the AFP level is very high, a biopsy may not be needed.
If looking at the liver is necessary to check for signs of disease, the doctor might order a computerized axial tomography (CAT) scan, magnetic resonance imaging (MRI) or a scan of the liver using a radioisotope (a harmless radioactive substance that highlights the liver), ultrasound or the doctor might look at the liver using a laparoscope, an instrument that is inserted through the abdomen and relays pictures back to a computer screen.
CT Scan (Computed Tomography)
 
Computerized tomography or CT scan is an X-ray technique that produces more detailed images of your internal organs than do conventional X-ray exams. This technology uses an X-ray-sensing unit, which rotates around your body and a large computer to create cross-sectional images of the inside of your body to obtain two-dimensional images of your liver. This test is very useful in identifying many types of liver tumors. It can provide precise information about the size, shape, and position of any tumors in the liver or elsewhere in the abdomen.
Instead of taking one picture like a standard x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these into images of slices of the part of your body that is being studied. The CT scan is one of the best tools for studying your chest and abdomen. It can be used to find out whether you have excess fat in your liver (fatty liver).
CT scanning is not painful. An iodine dye, usually given as a fluid to swallow, is used to show up the gullet (oesophagus), stomach and intestines (small bowel and colon). Alternatively, a dye may be injected into a vein to make your blood vessels and kidneys easier to see and to highlight the appearance of normal and abnormal tissue in organs such as the liver and spleen.
Ultrasound
Ultrasound is a routine procedure which can provide very useful information. The procedure is very safe and should not be painful, but it may take 10 to 15 minutes to complete. Ultrasound uses high-frequency sound waves to create images of organs and systems within your body to generate detailed pictures of your liver. This test can show masses growing in the liver, which can then be tested for cancer, if needed.
The ultrasound machine will have recorded the pictures of your liver. A report will be made by the radiologist, who is trained to examine the images. This report may be ready soon after your ultrasound or may take one to two weeks.
You should have an appointment arranged to discuss the result with your specialist or medical advisor. Sometimes the specialist will describe the type of picture received from your liver ultrasound as being ‘echogenic’. This means how clearly or ‘bright’ your liver can be seen on the ultrasound. The report will provide you and your specialist with information about the surface and the general shape of your liver, as well as any significant changes from its normal appearance. While ultrasound is able to highlight unexpected changes or anything that is not normal, it cannot show these in detail.
MRI (Magnetic Resonance Imaging)
MRI uses a type of tube scanner to provide a more detailed view of your organs than a CT scan. It is a relatively new kind of technology that creates powerful magnetic fields by releasing radio frequency energy to act on water molecules in your body. These emissions are a type of radio signal that can be picked up by the MRI equipment and relayed to a computer that is able to generate very detailed views of tissues within your body. MRI scans can be very helpful in looking at liver cancers. Sometimes they can tell a benign tumor from a malignant one. For this reason MRI is a very useful tool for investigating tumors both before and after treatment.
You will be required to remain very still. The scan is painless although some people may find being inside the scanner claustrophobic. It can take up to one hour but the majority of scans will take between 20 and 30 minutes.
X-Rays (X-Radiation)
In X-ray is a common and painless examination in which invisible radioactive waves are passed through your body to record an image of your body organs.
A special X-ray that studies the veins and arteries that supply blood to the liver is known as hepatic angiography. This X-ray may be needed if your diagnosis is still doubtful after a CT and MRI scan. The procedure uses a catheter (a thin, flexible tube) that is placed into a blood vessel through a small cut in your groin. A dye, referred to as a ‘contrast dye’ or ‘contrast medium’, is then injected through the catheter to light up the blood vessels to make them easier to see.
Laparoscopy
A laparoscopy is a procedure using a flexible (bendy) fibre optic tube with a tiny camera and a light on the end. This is called a laparoscope. It is inserted into your tummy through a small cut in your skin ('keyhole') to take pictures of your liver. If needed, a biopsy (see below) of your liver can be taken at the same time. A laparoscopy may also be used to follow up something seen on an X-ray or used alongside certain surgical procedures such as removal of the gallbladder (cholecystectomy) for gallstones.
A laparoscopy is performed under a general anaesthetic. Afterwards it can be painful (you may have a stitch or two), but tablet painkillers are usually enough to dull the pain. It is a good idea to have someone keeping an eye on you for 24 hours afterwards and you should not drive a vehicle during this time.
Liver biopsy is most useful in confirming a diagnosis of a potentially treatable condition. These potentially treatable liver diseases include chronic hepatitis B and C, hemachromatosis, autoimmune hepatitis and alpha-1-antitrypsin deficiency.
Whatever the tests required, your doctor will provide you with the best advice and opinions.
Disclaimer: The information provided is for educational and communication purpose only, for use in the maintenance and promotion of good health and should not be construed as personal medical advice or presented with the intention of diagnosing any disease or condition or prescribing any treatment. Bio Healthcare Enterprise shall hold No responsibility or liability on any untoward effects or incidents which may arise as a result of any misinterpretation of this information.
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