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

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

This blood test measures low-density lipoprotein (LDL) cholesterol, often called “bad” cholesterol. It is used to help assess cardiovascular risk and monitor cholesterol treatment.

Quick summary

["LDL cholesterol helps estimate the buildup of fatty plaque in the arteries and your risk of heart attack or stroke."]

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

Key facts at a glance

LOINC
43393-8
Short code
LDL4 SerPl-mCnc
Synonyms
LDL4 SerPl-mCnc
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 test measures the amount of LDL cholesterol in a blood sample. LDL carries cholesterol from the liver to body tissues, and higher levels can contribute to fatty plaque buildup in arteries.

Why might I need this test?

LDL cholesterol is usually measured as part of a lipid panel to help assess the risk of heart disease and stroke. It may also be checked to monitor treatment for high cholesterol or to evaluate risk factors such as diabetes, high blood pressure, smoking, or a family history of early heart disease.

How is the test performed?

A blood sample is drawn from a vein and analyzed by a laboratory. Some laboratories measure LDL directly, while others calculate it from other cholesterol and triglyceride results; the report identifies the method used.

How do I prepare for the test?

Fasting may or may not be required, depending on the test ordered and the laboratory. If instructed to fast, avoid food and drinks other than water for the period specified by your clinician, and continue medications unless directed 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.

◆Associated findings1

Short name

LDL cholesterol

Frequently asked questions

Is LDL cholesterol the same as “bad” cholesterol?
Yes. LDL is commonly called “bad” cholesterol because it can contribute to plaque buildup in the arteries.
Does this test require fasting?
It depends on the laboratory and the reason for testing. Your clinician or laboratory should tell you whether you need to fast and for how long.
Can medications or lifestyle changes lower LDL cholesterol?
Often, yes. Heart-healthy eating, physical activity, weight management, and stopping smoking may help, and your clinician may prescribe medication if needed. Do not stop or change prescribed medicines without medical advice.
  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