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Lactate Dehydrogenase (LDH) Activity in Serum/Plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures the activity of the enzyme lactate dehydrogenase (LDH), which plays a role in energy production in cells. It helps assess tissue damage or metabolic health.

Quick summary

["LDH helps identify conditions affecting cell health or damage."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
109410-1
Short code
LDH Msmt Fld
Synonyms
LDH Msmt Fld
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
140
Ref high
280
Critical range
— – 1000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83615
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

What Is LDH Used For?

LDH is often measured to evaluate conditions involving cell injury or breakdown, such as heart attacks, muscle injuries, liver disease, or certain cancers. It can also help diagnose infections or monitor metabolic disorders.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is processed to separate serum or plasma, and the LDH enzyme activity is measured using an automated laboratory method.

When Might You Need This Test?

Your healthcare provider may order LDH testing if you have symptoms like chest pain (possible heart issue), unexplained fatigue, muscle weakness, or if you have a known condition that could affect LDH levels, such as liver disease or cancer.

What Are Possible Results?

Results are reported as enzyme activity levels, but exact values depend on the lab and method used. Elevated LDH may suggest tissue damage or disease, while normal levels indicate healthy cell function.

Reference range

Adult: 140-280 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

LDH Activity

Frequently asked questions

Why might my LDH test be ordered if my symptoms aren’t directly related to a known condition?
Your doctor may order LDH testing as part of a broader evaluation to monitor for underlying issues, such as detecting early signs of organ damage, infections, or metabolic changes that aren’t immediately obvious.
Can LDH levels change with diet or exercise?
LDH levels can be influenced by certain medications, infections, or severe illness, but diet and exercise alone typically don’t significantly alter LDH activity unless there’s an underlying metabolic or tissue stress response.
How long does it take to get results from this test?
Results are usually available within 24 to 48 hours, depending on your lab’s processing schedule. Follow-up with your healthcare provider for interpretation.
  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 17, 2026. · Read our editorial policy