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LDL Cholesterol, Serum/Plasma — Substance Concentration

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

Measures low-density lipoprotein (LDL) cholesterol in blood to help assess cardiovascular risk and guide cholesterol management.

Quick summary

["LDL is often called “bad” cholesterol because higher levels can contribute to plaque buildup in artery walls."]

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

Key facts at a glance

LOINC
91112-3
Short code
LDL1c SerPl-sCnc
Synonyms
LDL1c SerPl-sCnc
Category
lipid
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
100
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83721
SNOMED
113079007
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 this test?

This blood test measures low-density lipoprotein (LDL) cholesterol. LDL carries cholesterol from the liver to body tissues and can contribute to the buildup of fatty plaque in arteries.

Why might I need this test?

The test is commonly used to assess cardiovascular risk, especially during routine screening or when monitoring treatment for high cholesterol. It may also be used to evaluate people with heart disease, stroke, diabetes, or other risk factors.

How is the test performed?

A blood sample is drawn and analyzed in a laboratory. LDL cholesterol may be measured directly or calculated from the results of a lipid panel.

How do I prepare for the test?

Follow your clinician’s instructions about fasting. Some lipid panels are measured after an overnight fast, while others do not require fasting. Drinking water is usually permitted unless you are told otherwise.

Reference range

Optimal: <100 mg/dLN/A

Specimen: serum

Fasting for 12-14 hours preferred. Water is permitted. Avoid alcohol for 24 hours before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A higher LDL cholesterol level can indicate increased risk of fatty plaque buildup in the arteries, which may lead to heart attack or stroke. Interpretation depends on your overall cardiovascular risk, medical history, medications, and other results in the lipid panel.

Short name

LDL cholesterol

Frequently asked questions

Is LDL cholesterol the same as total cholesterol?
No. Total cholesterol includes LDL, HDL, and other cholesterol-containing particles. LDL is measured separately because of its role in cardiovascular risk.
Does this test require fasting?
It depends on the laboratory and the reason for testing. Your clinician or laboratory will provide fasting instructions if they are needed.
Can lifestyle changes lower LDL cholesterol?
Yes. Dietary changes, regular physical activity, weight management, and not smoking may help. Your clinician can recommend additional treatment if needed.
  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