Liver Function Test (LFT) : Why perform; Laboratory Values. find clinical abnormalities

Liver Function Test (LFT)

Table of content 1-What is the Liver ? 2- Function of liver ? Role of the liver What are liver function tests? Why Perform LFT? Liver Disease Symptoms ? Substances measured in liver function testing Normal ranges of substances ? How is the sample collected for testing?

What is the Liver:

The liver is located in the right upper portion of the abdominal cavity just beneath the rib cage.If the liver is swollen, through inflammation or disease, it can swell out from under the ribs and make your tummy swollen.

The liver has many functions that are vital to life. Briefly, some of the important functions of the human liver are

Liver

Function of liver :

•Detoxification of blood

•Production of important clotting factors , albumin, and many other important proteins

•Metabolizing (processing) medications and nutrients

•Processing of waste products of hemoglobin and other cells

•Storing of Vitamin K,Vitamin A , Vitamin D Iron ,copper, fat, cholesterol, and bile

Liver Anatomy

•Glycogen (a carbohydrate energy store), which it makes from glucose.

•Glucose, made and released into the blood from glycogen, proteins and fats.

•Many essential proteins and amino acids .

•Many of the clotting factors that help your blood to clot normally.

•Plays a part in red blood cell production.

•Albumin, the main protein in your blood, which bulks out your serum and enables it to carry essential substances around the body.

• Angiotensinogen, which plays a role in blood pressure control.

Role of the liver :

The role of the liver is to keep the body’s complex internal chemistry in balance. It takes raw nutrients from our digestive system (in the form of carbohydrates, protein, amino acids, etc) and processes them so they can be stored and sent to different parts of our body in the right form and quantity.

The liver regulates the level of sugars in our blood and manufactures bile (which breaks down fats in our stomach). It also helps remove toxins, drugs and hormones from our bloodstream.

What are liver function tests :

Liver function tests (also known as a liver panel) are blood tests that measure different enzymes, proteins, and other substances made by the liver and monitor liver disease or damage.An initial step in detecting liver damage is a simple blood test to determine the level of certain liver enzymes (proteins) in the blood.

Liver function Test

A liver function test (LFT) is a blood test that gives an indication of whether the liver is functioning properly. The test is also very useful to see if there is active damage in the liver (hepatitis) or sluggish bile flow (cholestasis).

Liver function tests measure the amount of particular chemicals in the blood. This gives a gauge of possible damage to liver cells - damage that can be caused by many things including HCV. So a more correct term for a liver test would actually be a liver dysfunction test

Your liver does all kinds of work that’s crucial for your health. It helps break down food, clean your blood, make proteins, and store energy.

People reading this page should keep in mind that abnormalities within liver tests don’t necessarily point to specific diseases. Only a physician who knows all the aspects of a specific case can reliably make a diagnosis.

Why Perform LFT :

A variety of diseases and infections can cause acute or chronic damage to the liver, causing inflammation, scarring, bile duct obstructions, clotting abnormalities, and liver dysfunction. Alcohol, drugs, some herbal supplements, and toxins can also pose a threat.

Liver Disease Stages

•to check for damage from liver infections, such as hepatitis B and hepatitis C

•to monitor the side effects of certain medications known to affect the liver

••Monitor treatment of liver disease. These tests can show how well the treatment is working

•Measure the severity of a disease, particularly scarring of the liver (cirrhosis)

•if you already have a liver disease, to monitor the disease and how well a particular treatment is working

•if you’re experiencing the symptoms of a liver disorder

•Monitor side effects of certain medicines

•if you have certain medical conditions such as high triglycerides, diabetes, high blood pressure, or anemia

•if you drink alcohol heavily

•if you have gallbladder disease

Liver Disease Symptoms :

The liver has multiple functions. It makes many of the chemicals required by the body to function normally, it breaks down and detoxifies substances in the body, and it also acts as a storage unit. When the liver is damaged from disease, medication, alcohol, or other factors., a person may have symptoms of liver disease such as

•Nausea and vomiting

•jaundice (yellowing of the skin)

•fatigue

•weakness

•dark urine

•shortness of breath

•excessive bruising or bleeding

•leg swelling

• pruritus

•diarrhoea

•unexplained weight loss

Substances measured in liver function testing :

Aspartate aminotransferase (AST) :

AST is a type of protein called an enzyme that is found in the liver as well as many muscles and organs. Is an enzyme produced in hepatocytes (the major type of liver cells).

ALT level in the blood is Increased when hepatocytes are damaged or die - all types of hepatitis (viral, alcoholic, drug induced etc) cause hepatocyte damage. Levels of ALT may equate to the degree of cell damage but this is not always the case, particularly with hepatitis C.

•AST level under 40 IU/L is considered normal.

Alanine transferase (ALT) :

ALT is mainly only found in your liver, so it’s a good indicator of your liver function. A high ALT level can be a sign of liver damage. An ALT level between:

•10-50 IU/L is considered normal for men

•10-35 IU/L is considered normal for women

Values of LFT's

Gamma-glutamyl transferase (GGT) :

GGT is an enzyme found in the liver and other organs. Is an enzyme produced in bile ducts that may be elevated due to bile duct illness. The GGT test is extremely sensitive and may be elevated due to any type of liver disease or by different drugs, including alcohol, even when liver disease is minimal.

GGT levels are sometimes elevated even in the case of a normally functioning liver. GGT rises to 2-3 times the upper limit of normal in non-alcoholic fatty liver disease (NAFLD). This condition is increasingly common and can progress to scarring or inflammation of the liver. Transaminase levels also tend to rise in NAFLD.

•under 60 IU/L is considered normal for men

•under 42 IU/L is considered normal for women

L-lactate dehydrogenase (LD):

LD is an enzyme found in the liver. Elevated levels may indicate liver damage but can be elevated in many other disorders.

• 2 to 12 years 110–295 U/L

•Older than 12 years 100–190 U/L

Alkaline phosphatase (ALP):

A family of enzymes produced in the bile ducts, intestine, kidneys, placenta and bones comes mainly from the cells lining bile ducts and from bones - particularly growing bones.

It rises if there is slow or blocked flow in the bile ducts, if the bile ducts are damaged and in bone disorders it rises when you have Gallstones. Hepatitis of any cause, Cirrhosis, Bile duct blockage of any cause.

•under 104 IU/L is considered normal for men

•under 129 IU/L is considered normal for women

Bilirubin :

Bilirubin is a yellowish substance made during the body's normal process of breaking down red blood cells. Bilirubin is found in bile, a fluid in your liver that helps you digest food. If your liver is healthy, it will remove most of the bilirubin from your body.

Bilirubin Metabolism

It is the yellowish pigment responsible for jaundice. Bilirubin levels can be raised due to many different liver diseases, as well as conditions other than liver disease, e.g. gallstones. In cases of long term liver illness (chronic hepatitis)

The level usually stays within the normal range until significant liver damage has occurred and cirrhosis is present. In cases of short term liver illness (acute hepatitis), elevated bilirubin levels indicate the severity of the acute illness.

•under 24 umol/L is considered normal for men

•under 15 umol/L is considered normal for women

Globulin :

Describes the specific level of globulins - which include antibodies. This measure can be raised when liver cells are damaged due to autoimmune liver damage or to long-standing liver disease of many types, particularly when cirrhosis exists.

•Normal globulin levels range from 19-35 g/L.

Albumin :

If your liver or kidneys aren’t working properly, it can cause your albumin levels to drop. This might be caused by a poor diet, an infection, kidney disease, or inflammation.

•Normal albumin levels range from 34-50 g/L.

Prothrombin time (PT) test:

This test measures how long it takes your blood to clot. If it takes a long time, that could be a sign of liver damage. Medications that thin your blood

•Prothrombin time has a normal range of 9.4–12.5 seconds

How is the sample collected for testing :

Sample Collection

A blood sample is obtained by inserting a needle into a vein in the arm.