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Serum Lactate Concentration (Quantitative)

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

This test measures the amount of lactate, a byproduct of energy production in your body, in your blood serum. It helps doctors assess how well your body is using oxygen and managing energy.

Quick summary

["Lactate levels can indicate how your body is handling oxygen and energy, especially during illness or exercise."]

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

Key facts at a glance

LOINC
57729-6
Short code
Lactate 6M p chal SerPl-mCnc
Synonyms
Lactate 6M p chal SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Critical range
— – 4 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors may order this test to check for conditions affecting oxygen use, such as heart problems, infections, or severe illness. It can also be used during surgery or critical care to monitor how well your body is responding to treatment.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Higher-than-normal levels may suggest your body isn’t getting enough oxygen (like in shock or heart failure), while very low levels could indicate unusual metabolic issues. Your doctor will discuss results with you based on your health.

Common Conditions Monitored

This test is often used in emergencies, during surgery, or in intensive care to track how well your body is handling energy and oxygen, especially in cases of sepsis, heart problems, or severe infections.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Lactate is a key marker for assessing tissue hypoxia (low oxygen) and metabolic acidosis (acid buildup). Elevated levels can signal poor perfusion (blood flow) or organ dysfunction, guiding urgent treatment decisions in critical care settings.

Short name

Lactate Level

Frequently asked questions

Why might my doctor order this test?
Your doctor may order it if you’re critically ill, recovering from surgery, or experiencing symptoms like confusion, rapid breathing, or low blood pressure, which could indicate poor oxygen use.
What does a high lactate level usually mean?
A high lactate level often means your body isn’t getting enough oxygen where it’s needed, which can happen in conditions like heart failure, infections, or severe dehydration. Your doctor will review your symptoms and other test results to understand the cause.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor specifies otherwise. Some tests may require fasting, but this one does not.
  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