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Low-Density Lipoprotein Cholesterol, Serum/Plasma — Substance Concentration

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

Measures LDL cholesterol in blood to help assess cardiovascular risk and guide cholesterol treatment.

Quick summary

["Higher LDL cholesterol can increase the risk of heart disease and stroke."]

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

Key facts at a glance

LOINC
56135-7
Short code
IDL2c SerPl-sCnc
Synonyms
IDL2c SerPl-sCnc
Category
lipid
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 test measures low-density lipoprotein (LDL) cholesterol in serum or plasma. LDL is sometimes called “bad” cholesterol because it can build up in artery walls.

Why might I need this test?

An LDL cholesterol test may be part of a lipid panel or used to monitor cholesterol-lowering treatment. It helps assess your risk of heart disease and stroke, especially when combined with other cholesterol results and personal risk factors.

How is the test performed?

A blood sample is drawn, and the serum or plasma portion is analyzed in the laboratory. The result may be reported on its own or as part of a complete lipid panel.

How do I prepare for the test?

Fasting may be requested, so follow your clinician’s or laboratory’s instructions. Do not stop prescribed medicines unless your clinician tells you to, because some medicines can affect cholesterol levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A high LDL cholesterol level may increase the risk of plaque buildup in the arteries, heart disease, and stroke. Low LDL cholesterol can occur with certain medicines, illnesses, or nutritional conditions. Your clinician will interpret the result alongside HDL cholesterol, triglycerides, total cholesterol, and your overall cardiovascular risk.

Short name

LDL Cholesterol (LDL-C)

Frequently asked questions

Is LDL cholesterol the same as total cholesterol?
No. Total cholesterol includes cholesterol carried by several types of blood particles, while LDL cholesterol measures the amount found in LDL particles.
Do I need to fast before this test?
Fasting is not always required, but it may be requested for a lipid panel or when comparing results over time. Follow the specific instructions provided by your clinician or laboratory.
How often is LDL cholesterol checked?
The interval depends on your health, risk factors, and treatment plan. It may be checked during an initial assessment, after a medication change, or during routine monitoring.
  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