Skip to content

Serum or Plasma Lactate Concentration

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.

Quick summary

["Lactate helps doctors assess how well your body is using oxygen and managing energy during activity or illness."]

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

Key facts at a glance

LOINC
59012-5
Short code
Lactate 15M p chal SerPl-sCnc
Synonyms
Lactate 15M p chal SerPl-sCnc
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 how your body uses oxygen, such as severe infections, heart or lung problems, or metabolic disorders. It can also help monitor patients with conditions like shock, sepsis, or during surgery.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where lactate levels are measured using a specialized test that detects the chemical concentration.

What to Expect Before the Test

You may be asked to fast for a few hours before the test, but this isn’t always necessary. Wear comfortable clothing and avoid tight sleeves for easy access. Inform your doctor about any medications or supplements you’re taking.

What to Expect After the Test

The blood sample is processed quickly, and results are often available within a few hours. You can usually return to your normal activities immediately. There may be mild bruising or soreness at the injection site, which typically goes away quickly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lactate

Frequently asked questions

Why might my doctor order this test?
Your doctor may order this test to evaluate your body’s ability to use oxygen properly, especially if you have symptoms like rapid breathing, confusion, or signs of poor circulation. It’s often used in emergency settings or during monitoring for severe illnesses.
What does a high or low lactate level mean?
A high lactate level can signal conditions like shock, severe infections (sepsis), or problems with how your heart or lungs function. A low level is less common but might be associated with certain metabolic or genetic conditions. Your doctor will discuss the results with you in the context of your overall health.
Do I need to prepare for this test?
Preparation may vary. Some patients are asked to fast for a few hours before the test, but others don’t need to. Always follow your doctor’s instructions. Avoid strenuous activity or taking certain medications that could affect results.
  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