What Is a SGPT Blood Test?
An SGPT blood test is a test used to measure the amount of the enzyme glutamate pyruvate transaminase (GPT) in blood.
This enzyme is found in cells of the heart, kidneys, muscles and pancreas in small amounts, but it is in much greater concentration in the liver. This test is sometimes called ALT. You may hear your physician refer to it as a liver function study, where it is also combined with several other tests, all of which test how well the liver is functioning.
An SGPT test is done to see if the liver is diseased or damaged. Although there is normally a low level of GPT in the bloodstream, it will greatly increase in the presence of certain diseases, such as cirrhosis and hepatitis. The use of certain medications, such as statins to lower cholesterol, can also irritate the liver causing GPT to be released. This is why doctors check the liver functions carefully whenever you are on certain types of drugs. Early detection of elevated GPT levels can let the doctor know when to decrease or eliminate the use of certain drugs to prevent permanent damage to the liver.
Normal results of SGPT can vary from one lab to another. The lab performing the SGPT test will print their normal values on the lab report. Most labs consider a GPT level of 0 to 30 units per liter. The level of GPT may be elevated considerably if you drink too much alcohol, or have mononucleosis, chronic liver damage or disease, gallstones or gallbladder disease or certain types of cancer. No medical conditions are known to cause a person to have a GPT level that is too low.
If the SGPT test is extremely elevated, your physician may request that you have an ultrasound performed on your liver. This will determine if there is an underlying disease factor and will help the physician decide what to do to lower the GPT level. If the increased GPT level is caused by the use of a drug, discontinuing use of the drug or replacing it with another drug will usually let the GPT levels fall back into the normal range. If the elevated GPT levels are caused by other problems with the liver or gallbladder, the physician will probably refer you to a specialist, such as a gastroenterologist, for further evaluation.
The SGPT blood test is performed on blood serum. The blood is drawn from a vein and spun in a centrifuge to separate the serum from the cells. No special preparation for the test is needed; however, do not perform strenuous exercise immediately before having the test done. You should also avoid taking herbs such as echinacea and valerian, as they can affect the SGPT results.
If you have an abnormal test result, you will probably be asked to have the test done again to be sure the first test was accurate.