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Lactate Dehydrogenase (LDH) Activity in Serum/Plasma

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

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

Quick summary

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

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

Key facts at a glance

LOINC
13888-3
Short code
LDH3 CFr Ur Elph
Synonyms
LDH3 CFr Ur Elph
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
140
Ref high
280
Critical range
7.2 N/A – 7.6 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
electrophoresis
CPT
83615
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Doctors may order LDH testing to evaluate symptoms like fatigue, muscle weakness, or organ-related issues. It can also help diagnose or monitor conditions such as heart attacks, liver disease, muscle injuries, or certain cancers.

What Does the Test Involve?

A blood sample is taken from a vein in your arm. The lab analyzes the enzyme activity in your serum or plasma, which is a liquid part of your blood without blood cells.

What Are Common Results and Interpretations?

While exact reference ranges vary by lab, elevated LDH levels may suggest damage to cells in organs like the heart, liver, or muscles. Lower levels might be less common but could indicate certain metabolic or genetic conditions.

What Conditions Might Affect Results?

LDH levels can be influenced by conditions like heart attacks, liver disease, muscle injuries, anemia, or certain infections. Medications, pregnancy, or recent blood transfusions may also impact results.

Reference range

Adult: 140-280 U/LN/A

Specimen: urine

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

What does an elevated LDH level mean?
An elevated LDH level may indicate damaged or stressed cells in organs like the heart, liver, or muscles. It can help identify conditions such as heart attacks, liver disease, or certain cancers, but further testing is needed to determine the exact cause.
What if my LDH level is normal?
A normal LDH level means there is no significant evidence of widespread cell damage detected by this test. However, it does not rule out all possible conditions—additional tests may still be needed if you have symptoms or concerns.
Can LDH levels change with diet or exercise?
LDH levels can be influenced by muscle activity (e.g., intense exercise) or certain foods, but diet alone typically does not significantly alter the test results. Always discuss any recent physical activity or dietary changes with your healthcare provider before testing.
  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