Lactate Test Test

This test measures the level of lactate (lactic acid) in your blood or cerebrospinal fluid. High levels can indicate a buildup of lactate, which may lead to lactic acidosis, a serious condition.

What this test measures

This test measures the level of lactate, also called lactic acid, in a sample of your blood. In certain cases, cerebrospinal fluid (CSF) may be used.

What your results mean

Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.

Higher-than-normal results

A high level of lactate in blood usually means you have either hyperlactatemia (mildly or moderately high lactate with normal blood acidity) or lactic acidosis (high lactate making blood too acidic). High lactate in CSF likely means bacterial meningitis.

Lower-than-normal results

Low levels of lactate are rare and not considered to be a medical concern.

Frequently asked questions

What is a lactate test?

It measures the level of lactate (lactic acid) in your blood or cerebrospinal fluid.

Why is lactate measured?

To diagnose lactic acidosis and evaluate conditions that may cause lactate buildup.

What does a high lactate level mean?

It may indicate hyperlactatemia or lactic acidosis. In CSF, high levels suggest bacterial meningitis.

What does a low lactate level mean?

Low levels are rare and not considered a medical concern.

Can a lactate test diagnose the cause of high lactate?

No, it only shows abnormal levels. Your provider will use other tests and your medical history to find the cause.

Sources

MedlinePlus: Lactate Test — NIH MedlinePlus

Last updated July 7, 2026. Information is aggregated from official public sources and is not a substitute for professional medical care.