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. When the oxygen level in the body is
carbohydrate breaks down into water and carbon
dioxide. When the oxygen level is low, carbohydrate breaks down for energy and
makes lactic acid.
Lactic acid levels get higher when strenuous
exercise or other conditions—such as
heart failure, a severe infection (sepsis), or
shock—lower the flow of blood and oxygen throughout
the body. Lactic acid levels can also get higher when the liver is severely
damaged or diseased, because the liver normally breaks down lactic acid.
Very high levels of lactic acid cause a serious, sometimes
life-threatening condition called lactic acidosis. Lactic acidosis can also
occur in a person who takes metformin (Glucophage) to control
diabetes when heart or kidney failure or a severe
infection is also present.
A lactic acid test is generally done on
a blood sample taken from a vein in the arm but it may also be done on a sample
of blood taken from an artery (arterial blood gas).
Why It Is Done
A test for lactic acid is done
- Check for lactic acidosis. Symptoms of lactic
acidosis include rapid breathing, excessive sweating, cool and clammy skin,
sweet-smelling breath, belly pain, nausea or vomiting, confusion, and
- See whether the right amount of oxygen is reaching the body's
- Find the cause for a high amount of acid (low
pH) in the blood.
How To Prepare
To prepare for a lactic acid
- Do not eat or drink anything other than water
for 8 to 10 hours before the test.
- Do not exercise for several hours before the test. Do not clench
your fist while having your blood drawn for a lactic acid test. These
activities may change the results.
How It Is Done
The health professional drawing blood
- Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein. An elastic band may not be used for a
lactic acid test because a band around the arm muscle may cause a false
increase in lactic acid.
- Clean the needle site with
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
- Remove the band from your arm when enough blood is
- Put a gauze pad or cotton ball over the needle site as
the needle is removed.
- Put pressure to the site and then a