Alanine Aminotransferase: Low and High Levels

HOW DOES ALANINE AMINOTRANSFERASE DO ITS JOB?

ALT helps create the substances mentioned in the previous section by causing a chemical reaction. The

chemical reaction is caused by moving molecules from l-alanine (a type of amino acid) to alpha-

ketoglutarate (a type of salt). This reaction is reversible, however. Molecules are the smallest naturally

occurring particles of a substance. See the previous section for a definition of amino acid. The

molecules that ALT move are called amino groups. Amino groups are part of amino acids. They are

made up of one part nitrogen and two parts hydrogen. Nitrogen and hydrogen are both natural

elements. To sum it up, picture ALT as a builder that removes pieces from one structure to help create

another structure.

WHAT IS THE NORMAL LEVEL OF ALANINE AMINOTRANSFERASE IN THE BLOOD?

The normal range of ALT on blood work tests is less than 35 units per liter (U/L) or 5 to 35 International

Units per liter (IU/L). However, it is important to keep in mind that these ranges will be different

depending on the machine used to do the blood test. Always use the normal range printed on the lab

report to decide what range is normal. Regarding the way in which these ranges are measured, a unit is

a specific amount of a substance that is needed to produce a desired effect. A unit's value will differ for

each type of substance. An International Unit is very similar to a unit but is based on a different type of

scale. The value of an International Unit will also differ for each type of substance. A liter is a

measurement of the amount of space that a liquid takes up in a container, which is equal to 1.056688

quarts. To understand this better, picture a gallon of milk. It takes 4 quarts of milk to make up one gallon

of milk. Since one liter is a little bit more than one quart, 4 liters of milk is a little bit more than one gallon

of milk.

WHAT CAN CAUSE THE LEVEL OF ALANINE AMINOTRANSFERASE TO BE TOO HIGH?

To begin with, since there are many reasons why ALT levels can be high it is important that additional

testing is done to determine the exact cause. When an organ or body tissue is injured, increased levels

of ALT are released into the blood. The greater the degree of tissue damage, the greater the degree of

ALT that is released. When ALT is high, the most common cause is liver damage. The liver is the largest

organ in the body and is responsible for filtering (removing) harmful chemical substances, producing

important chemicals for the body, and other important functions. Long-term or sudden liver damage can

cause a rise in ALT levels.

Damage to other areas such as the heart, muscles, lungs, pancreas (a long organ in the back of the

belly) or the kidney, can cause the levels of ALT to increase. The kidneys are two organs located on

each side of the spine, behind the stomach. The kidneys filter (remove) wastes from the blood.

Inflammation of the heart can also cause high ALT levels. The ALT levels usually are only mildly

increased after a heart attack.

If the ALT levels are very high (up to 50 times higher than the normal range), chances are that the cause

is liver damage caused by viral hepatitis (an infection of the liver that causes liver inflammation), drugs,

or chemicals. People with hepatitis may have ALT levels that are 20 to 50 times higher than the normal

level. However, patients with tumors (types of abnormal tissue) of the liver or cirrhosis (a type of disease

that destroys the liver) usually only have ALT levels that are 2 to 4 times the normal level. People that

have mononucleosis may have high ALT levels. Mononucleosis is an abnormal increase in a type of

white blood cell in the blood. A cell is the smallest, most basic unit of life, that is capable of existing by

itself. White blood cells help the body fight against infections.

People who abuse alcohol may have mild to moderately increased ALT levels. In addition, high levels of

ALT can also happen when people drink too much alcohol and take acetaminophen. Acetaminophen is a

substance that fights against fevers and infections. An example of a medication that contains

acetaminophen is Tylenol. Taking narcotics can also cause ALT levels to be high. Narcotics are types of

substances or drugs that relieve pain and cause feelings of pleasure. Medications that can cause liver

damage may also lead to raised ALT levels. Such medications include heparin (a blood thinning

medication), tetracycline (a type of medication that fights infections), and metyhldpopa (a medication

used to treat high blood pressure).

Severe burns, shock, and polymyositis can cause high ALT levels. Polymyositis is an inflammation of

many muscles, and is usually accompanied by deformity, abnormal fluid buildup in tissues, difficulty

sleeping, tension, sweating, and pain. Dermatomyositis, which a disease that causes destruction of

muscle tissue, can also raise ALT levels. Rapid growth can cause mildly increased ALT levels, especially

in pregnant women and young children. High ALT levels can be caused by seizures (sudden, violent,

involuntary muscle movements). A type of infectious virus known as Epstein-Barr virus can also cause

high levels of ALT.

WHAT CAN CAUSE THE LEVEL OF ALANINE AMINOTRANSFERASE TO BE TOO LOW?

Low levels of ALT are normally found in the blood. Thus, it is not usually a cause for concern. However,

a low ALT level can be caused by poor nutrition. A low ALT level can also be caused by infections of the

urinary tract. The urinary tract is the part of the body that deals with the formation and excretion of urine

(pee). To excrete means to release from the body as waste.

WHAT CAN CAUSE ALANINE AMINOTRANSFERASE LEVELS TO BE INACCURATE?

Sometimes, there are factors that do not involve the patient that can cause the test results to be

inaccurate. These factors include rough handling, improper refrigeration, or contamination of the blood

sample.

WHAT ELSE IS ALANINE AMINOTRANSFERASE CALLED?

Alanine aminotransferase is also known as glutamic-pyruvic transferase (GPT), serum glutamic-pyruvic

transferase (SGPT), and alanine transaminase.