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Lactate Dehydrogenase (LDH) in Serum/Plasma

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

This test measures the level of lactate dehydrogenase, an enzyme found in many tissues throughout your body. It helps assess cell damage or disease activity in conditions like heart disease, liver disease, or certain cancers.

Quick summary

["LDH helps identify tissue injury or metabolic disorders by tracking enzyme levels in your blood."]

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

Key facts at a glance

LOINC
109686-6
Short code
LDH Msmt Pcar
Synonyms
LDH Msmt Pcar
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 checked alongside other tests to diagnose or monitor conditions such as heart attacks (myocardial infarction), liver disease, muscle injuries, or certain types of cancer. High levels may suggest widespread cell damage, while low levels are less commonly significant but could indicate certain metabolic or genetic conditions.

Common Conditions Monitored

Doctors may use LDH to evaluate symptoms like chest pain (possible heart attack), unexplained fatigue, or jaundice (yellowing of skin/eyes). It can also help guide treatment decisions for conditions like hemolytic anemia or certain infections.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where LDH activity is measured using an enzymatic method. Results are typically available within 24 hours.

What Do Results Mean?

Results are compared to a reference range specific to your lab, but they don’t provide absolute values for interpretation. Elevated LDH may indicate tissue damage, while persistently low levels may warrant further investigation for rare conditions.

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 Blood Test

Frequently asked questions

Why might my doctor order this test?
Your doctor may order LDH testing if you have symptoms like chest pain, unexplained fatigue, or signs of organ damage (e.g., liver or muscle issues). It’s also used in cancer monitoring to track treatment response or disease progression.
What causes LDH levels to change?
LDH levels can rise due to cell damage from conditions like heart attacks, liver disease, muscle injuries, or infections. Certain cancers (e.g., lymphoma) may also elevate LDH. Rarely, genetic disorders or medications can affect levels.
Do I need to prepare for this test?
No special preparation is needed, but avoid strenuous exercise or alcohol consumption 24 hours before the test, as they may influence 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