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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 conditions affecting cell damage or metabolism.

Quick summary

["LDH helps diagnose and monitor conditions linked to cell injury or metabolic dysfunction."]

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

Key facts at a glance

LOINC
68387-0
Short code
LDH Prt L to P-cCnc
Synonyms
LDH Prt L to P-cCnc
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
Method
reaction-lactate-to-pyruvate
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 commonly used to identify and monitor conditions that cause damage to cells, such as heart attacks (myocardial infarction), liver disease, muscle injuries, or certain cancers. It can also help track the progression of diseases like anemia or infections.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The lab then measures LDH activity in your serum or plasma using an enzymatic method to detect how well your cells are functioning under stress.

What Might Affect Results?

Factors like recent exercise, certain medications, or underlying health conditions (e.g., liver disease, heart problems) can influence LDH levels. Always discuss your full medical history with your healthcare provider.

Common Conditions Monitored

Elevated LDH may signal conditions like heart attacks, liver disease, muscle injuries, or blood cancers. Lower-than-normal levels are less common but can occur in rare metabolic disorders.

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.

Clinical Significance: LDH Levels and Health Risks

Short name

LDH Activity

Frequently asked questions

Why was this test ordered?
Your doctor may have ordered LDH testing to investigate symptoms like chest pain, fatigue, unexplained muscle weakness, or signs of organ damage. It can also help evaluate conditions like anemia or cancer.
What do my LDH results mean?
Results alone don’t diagnose a condition—they’re part of a larger picture. Your doctor will compare your LDH level to your symptoms, medical history, and other test results to determine the next steps.
Can I influence my LDH levels?
Yes—avoiding strenuous exercise before testing, managing chronic conditions (like diabetes or heart disease), and following your doctor’s advice can help ensure accurate 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 17, 2026. · Read our editorial policy