How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

Risks

There is very little chance of a problem from having blood sample taken from a vein.

• You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
• In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
• Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

A lactic acid test is a blood test that measures the level of lactic acid made in the body. Most of it is made by muscle tissue and red blood cells.

Normal

The normal values listed here-called a reference range-are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what’s normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Results are ready in 1 day.

High values

A high lactic acid value indicates lactic acidosis, which can be caused by:

• Severe loss of water from the blood (dehydration).
• Blood problems, such as severe anemia or leukemia.
• Liver disease or liver damage that prevents the liver from breaking down lactic acid in the blood.
• Conditions such as severe bleeding, shock, severe infection, heart failure, blockage of blood flow to the intestines, carbon monoxide poisoning, or pulmonary embolism that prevent adequate oxygen from reaching the body's cells.
• Extremely strenuous exercise or extreme overheating.
• Poisoning by alcohol (ethanol), wood alcohol (methanol), or antifreeze (ethylene glycol).
• Some medicines, such as isoniazid for tuberculosis or metformin (Glucophage) for diabetes. Lactic acidosis is a concern for people who take Glucophage to control their diabetes, especially if they have poor kidney function.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Taking large doses of the medicine epinephrine.
• Taking medicines, such as isoniazid for tuberculosis or metformin (Glucophage) for diabetes.
• Using a lot of acetaminophen (such as Tylenol) or alcohol.
• Exercising prior to this test.
• Clenching a fist while the blood sample is being drawn. Also, lactic acid levels may be higher if the tourniquet is around your arm for a long time.