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Serum or Plasma Lactate Level

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of lactate, a byproduct of energy production in your body, typically drawn from blood.

Quick summary

["Lactate helps assess how well your body is using oxygen and producing energy, especially in critical situations."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
59032-3
Short code
Lactate Bld-mCnc
Synonyms
Lactate Bld-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Critical range
— – 4 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors may order lactate tests to evaluate conditions like low blood oxygen, severe infections, heart or lung problems, or shock. It can also help monitor how well treatments are working for conditions like sepsis or heart failure.

What to Expect Before the Test

You’ll typically have a small needle inserted into your arm or vein to draw blood. If you’re in a hospital, this may be done while you’re already receiving care. Avoid eating or drinking for 2–4 hours before testing if instructed.

What Happens During the Test?

Blood is collected in a tube and sent to a lab for analysis. The test usually takes a few minutes, and you’ll feel a brief pinch from the needle. No special preparation is needed beyond standard blood draw precautions.

What Are the Results Measured Against?

Lactate levels vary based on health, activity, and medical conditions. Higher-than-normal levels may signal poor oxygen use, while very low levels could indicate unusual metabolic processes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Lactate is a critical marker for conditions like sepsis, heart failure, or severe dehydration. High levels often appear early in critical illnesses and help guide treatment decisions, such as oxygen therapy or fluid replacement.

Short name

Lactate

Frequently asked questions

Why might my doctor order this test?
Your doctor may order it to check for conditions like low blood oxygen, infections, or heart/lung problems, especially if you’re already receiving medical care for a serious illness.
What does a high lactate level mean?
A high lactate level often means your body isn’t using oxygen efficiently, which can happen with infections, heart failure, or shock. Your doctor will discuss results with you in detail.
Can I eat or drink before this test?
Follow your doctor’s instructions—some tests require fasting, while others don’t. Generally, avoid food/drink for 2–4 hours if directed, but always confirm with your healthcare provider.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy