Liver function tests (often abbreviated as LFTs) are blood-sample-based tests that measure the chemicals produced by the liver as well as the organ’s overall capacity to function. The many chemicals produced by the liver flow into the bloodstream and bile, ultimately affecting the entire body. The liver’s ability to produce these chemicals can be affected by a number of different liver disorders ranging from hepatitis to cirrhosis. LFTs can help patients better understand what conditions they are suffering from and what they can do to prevent further damage to their livers.
Who Should Undergo a Liver Function Test?
You may wish to consider undergoing a LFT if…
- you are suffering from symptoms that may be associated with liver conditions.
- you believe that you have a liver problem, but are not sure which condition you are suffering from.
- you have a liver condition and would like to monitor your liver function as a part of disease management.
- you fear that a particular medication you are taking may be causing liver damage.
- you are an alcoholic or former alcoholic and want to monitor liver damage.
- you may have been exposed to a hepatitis virus or are genetically prone to a liver health condition.
If you or someone you care about is planning to undergo a liver function test, it can be beneficial to understand the many chemicals that are measured by the test and what these measurements mean in regards to liver health.
Some of the main measurements taken by LFTs include the following:
Albumin: Albumin is one of the most important proteins made by the liver. Some liver disorders affect the liver’s capacity to produce albumin. Low levels of albumin in the bloodstream may be indicative of a potential liver problem. Albumin levels may be measured on their own or may be lumped together with a measurement of all liver proteins.
Alanine Transaminase (ALT): Alanine transaminase is an enzyme found in abundance throughout liver cells. The enzyme is used to aid in the break-down of proteins in the liver. If test results indicate that there are high levels of ALT found in the bloodstream, this is generally indicative of liver damage. High ALT measurements may indicate that the liver is inflamed or damaged, which may be the result of hepatitis or other liver conditions.
Alkaline Phosphatase (ALP): ALP is an enzyme found in the cells that line the bile ducts of the liver. In patients suffering from bile duct blockage or other liver diseases, a test may indicate that ALP levels in the blood are elevated. ALP can also be elevated in children, as the enzyme is released from growing bones. In conjunction with other LFT results, an elevated ALP reading may indicate a liver condition.
Aspartate Aminotransferase (AST): Aspartate aminotransferase is an enzyme that is also found throughout the liver. A high AST level may indicate liver damage, but is not necessarily indicative of a liver condition. AST levels may be elevated by other health conditions as well, such as muscle damage or heart problems. ALT is a much more specific indicator of poor liver functioning; in conjunction, however, high ALT and AST levels suggest that there is almost certainly something wrong with the liver.
Bilirubin: Bilirubin, as its name suggests, is connected to the liver’s production of bile. The substance provides bile with its distinctive yellow-green color. Bilirubin, which is derived from hemoglobin, will make a person appear jaundiced (yellow-skinned appearance) if an excess of the substance begins circulating in the bloodstream.
There are two levels of bilirubin measured on most LFTs: “conjugated” bilirubin and “unconjugated” bilirubin.
If conjugated bilirubin levels are elevated, this generally indicates that a patient is suffering from a liver or bile duct problem. Problems that may lead to high conjugated bilirubin include gallstones stuck in the bile duct, hepatits, alcohol abuse, or other liver damage. If the natural flow of bile is blocked, conjugated bilirubin levels may be particularly high.
High unconjugated bilirubin levels tend to occur when an abnormally high level of red blood cells are broken down in the body. This may occur when the patient suffers from conditions such as hemolytic anemia, Crigler-Najjar syndrome, or Gilbert’s syndrome.
Other tests may be performed in addition to the liver function test depending on what conditions the patient may be suffering from. Normal ranges and values for liver tests may vary due to gender and may vary somewhat between laboratories. Remember to ask your doctor to explain the results of your LFT to you. Only your doctor can properly interpret the results of this test.
If you suspect that you are suffering from a liver condition, it is wise to consider undergoing a liver function test. Having your LFT results will give you the information you need to continue forward with the treatment and recovery process.