The lactate test is an essential medical tool for measuring lactic acid levels in the blood, indicative of various health conditions. By monitoring these levels, health professionals can diagnose problems such as lactic acidosis, assess cells' oxygen supply, and guide appropriate treatments.
This test measures the level of lactate, also called lactic acid, in a sample of your blood. In some cases, cerebrospinal fluid (CSF) may be used. Normally, you have low levels of lactate in your blood and CSF. High lactate levels can be a sign of a wide variety of medical conditions.
Lactate is primarily produced in your muscles and red blood cells when they break down food for energy. Most of the time, your cells use oxygen to break down food for energy. But if your cells can't get enough oxygen, they can switch to another energy-producing process that doesn't use oxygen. This rescue process produces lactate. Your liver and kidneys turn lactate into glucose (sugar) that your cells use for energy.
It's normal to have brief increases in lactate when exercising or doing other hard physical work. That's because your body uses more oxygen when you're physically active, which triggers your cells to produce energy without oxygen. In general, your lactate levels drop rapidly when you stop the activity.
But some medical conditions can cause a harmful accumulation of lactate. If lactate levels get too high, your blood becomes too acidic. This can lead to serious health problems and a life-threatening condition called lactic acidosis.
There are many types of conditions that can cause lactate to build up. They fall into two main groups:
A lactic acid test can help detect high levels of lactic acid before they cause serious health problems, but the test cannot diagnose the cause.
Other names: lactic acid test, lactic acid: plasma, L-lactate
A lactate blood test is most often used to diagnose lactic acidosis and determine its severity. It can also help assess and monitor many types of medical conditions that can cause lactate levels to rise.
If a person seems to have meningitis, an infection of the brain and spinal cord, the test can be used to help determine if it is caused by bacteria or a virus. Because meningitis is an infection of the brain and spinal cord, both cerebrospinal fluid and blood can be tested.
You may need a lactate test:
You may also need this test if your health care provider thinks you have signs and symptoms of any of the many conditions that can cause lactic acidosis.
If you have been diagnosed with high lactate levels, you may need repeated tests to monitor your condition.
If you have symptoms of meningitis, you may need to have your blood and cerebrospinal fluid lactate levels measured. Meningitis symptoms include:
A health professional will take a blood sample from a vein or artery. Blood from an artery may provide more accurate results than blood from a vein, so your provider may recommend this type of blood test, which is called an arterial blood gas (ABG) test.
To take a blood sample from a vein, a health professional will insert a small needle into your arm. After the needle is inserted, a small amount of blood will be collected in a test tube or vial. You may feel a slight prick when the needle goes in or out. This usually takes less than five minutes. Be sure not to shake your fist during the test, as this may temporarily increase lactate levels.
To take a blood sample from an artery, a provider will generally use an artery on the inside of the wrist. But the sample may be taken from an artery in your arm or groin. For a newborn, the sample may be taken from the baby's heel or from the umbilical cord shortly after birth.
If your blood sample is taken from your wrist, the provider will test your blood flow first. The provider will hold your wrist and apply pressure to the arteries to cut off blood flow to your hand for several seconds. Then, the provider will release your wrist to check how quickly blood flow is returning to your hand. If your blood flow is normal, the provider will collect a blood sample.
A blood sample taken from an artery tends to be more uncomfortable than most blood tests, which use a vein. So the provider may apply an anesthetic to your skin first. The provider will insert a needle with a syringe into the artery to remove some blood.
When the syringe is full, the supplier will bandage the puncture site. Pressure will be applied to the site for at least 5 minutes to stop the bleeding.
If meningitis is suspected, your provider may also take a sample of your cerebrospinal fluid during a procedure called a lumbar puncture. This is usually done in the hospital.
Your provider will tell you how to prepare for your test. Your provider can tell you to:
You may need to stop taking some medications before this test, so let your provider know everything you are taking. But don't stop taking any medication unless your provider tells you to.
There are very few risks in taking a blood test. You may feel a slight pain or bruise where the needle was inserted, but most symptoms go away quickly.
After taking blood from an artery, you may experience bleeding, bruising, or pain where the needle was inserted. Very rarely, the needle can damage a nerve or artery. You may be advised to avoid lifting heavy objects for 24 hours after the test.
The results of a lactate test can only show if you have abnormal lactate levels. They can't tell what's causing the problem.
A high level of lactate in a blood sample usually means that you have either hyperlactatemia or lactic acidosis:
Treatment for high lactate levels depends on the condition that causes lactate to build up in your blood. Your provider will consider your symptoms, medical history, and other test results to diagnose the cause.
If you have had a lactate test using cerebrospinal fluid:
Low lactate levels are rare and are not considered to be a medical concern.
If you have questions about your results, talk to your provider.
Learn more about lab tests, reference ranges, and understanding results.
Some medications can cause high levels of lactate, such as:
If you are concerned about how these medications may affect your risk of lactic acidosis, talk to your provider.
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