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LDL Cholesterol, Serum/Plasma — Mass Concentration

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

This blood test measures LDL (“bad”) cholesterol, a type of fat that can build up in artery walls and increase cardiovascular risk.

Quick summary

["LDL cholesterol helps assess how much “bad” cholesterol is in your blood and your risk of heart disease and stroke."]

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

Key facts at a glance

LOINC
91107-3
Short code
LDL3c SerPl-mCnc
Synonyms
LDL3c 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 concentration of LDL cholesterol in your blood. LDL is often called “bad” cholesterol because it can contribute to fatty buildup in arteries.

Why might I need this test?

LDL cholesterol is usually checked as part of a lipid panel to help assess your risk of heart disease, stroke, and conditions caused by narrowed arteries. It may also be monitored if you have heart disease, diabetes, or high cholesterol.

How is the test performed?

A blood sample is collected from a vein and tested in a laboratory. LDL cholesterol may be calculated from other lipid measurements or measured directly, depending on the laboratory method.

How do I prepare for the test?

Fasting for about 9 to 12 hours may be required, especially when the test is ordered with a complete lipid panel. Water is generally allowed; follow your clinician’s instructions and do not stop prescribed medicines unless advised.

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 total cholesterol?
No. LDL is one component of total cholesterol. The lipid panel measures total cholesterol, LDL, HDL, and triglycerides.
Does a high LDL result mean I have a heart attack?
No. LDL is a risk factor for cardiovascular disease, but one result alone cannot diagnose a heart attack or blocked artery.
Can I lower LDL cholesterol before my appointment?
A heart-healthy diet, regular physical activity, and taking prescribed medicines can help, but you should not change treatment based on a single result 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