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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 integrity or energy metabolism."]

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

Key facts at a glance

LOINC
19248-4
Short code
LDH2 SerPl Elph-cCnc
Synonyms
LDH2 SerPl Elph-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
electrophoresis
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 evaluate conditions like heart attack (myocardial infarction), muscle injury, 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, usually in the arm. The sample is processed to separate serum or plasma, then tested for LDH activity using an enzymatic method.

What Does a High or Low LDH Level Mean?

Elevated LDH may indicate damage to cells in organs like the heart, liver, or muscles. Very low levels are rare but could suggest certain metabolic or genetic conditions.

How Is the Test Interpreted?

Results are compared to a baseline or reference range provided by your healthcare provider. LDH activity can vary based on age, health status, and other factors.

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?
Your doctor may order this test to investigate symptoms like chest pain, unexplained fatigue, muscle weakness, or abnormal liver function tests. It can also be part of routine monitoring for conditions like heart disease or cancer.
What are the common reference ranges for LDH?
Reference ranges vary by lab and individual factors, so your results will be compared to your specific baseline or the lab’s standard. Exact values aren’t provided here due to variability.
Can lifestyle changes affect LDH levels?
Occasional physical activity or muscle strain may temporarily raise LDH, but diet or stress typically do not. Always discuss any changes 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 17, 2026. · Read our editorial policy