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LDL Cholesterol, Serum/Plasma — Ultracentrifugation, Mass Concentration

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

Measures LDL (“bad”) cholesterol in blood using ultracentrifugation, a method sometimes used when a direct LDL measurement is requested.

Quick summary

["This test measures LDL cholesterol, a blood lipid associated with the buildup of fatty plaque in arteries."]

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

Key facts at a glance

LOINC
18261-8
Short code
LDLc SerPl.Ultracent-mCnc
Synonyms
LDLc SerPl.Ultracent-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 low-density lipoprotein cholesterol (LDL-C) in your blood. LDL is sometimes called “bad” cholesterol because it can contribute to fatty plaque buildup in artery walls.

Why might I need this test?

Your clinician may order this test to assess your risk of heart disease and stroke, monitor cholesterol-lowering treatment, or evaluate unusually high or low cholesterol levels.

How is the test performed?

A blood sample is collected, usually by a vein in your arm. The laboratory separates and measures the cholesterol in different lipoprotein fractions using ultracentrifugation, which spins the sample at very high speeds to separate its components.

How do I prepare for the test?

Fasting for about 9 to 12 hours may be required, and water is usually allowed. Follow your clinician’s instructions, especially if you take cholesterol-lowering medicines, because food and medication can affect the result.

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. Total cholesterol includes cholesterol carried by all major lipoproteins, while this test measures the portion found in LDL particles.
Why is ultracentrifugation used for some LDL cholesterol tests?
Ultracentrifugation physically separates lipoprotein fractions before measuring them. It may be used when a direct laboratory measurement is preferred over an estimated calculation.
Do I need to fast before this test?
Fasting may be required, commonly for 9 to 12 hours. Ask your clinician or the laboratory for specific instructions because some tests can be performed without fasting.
  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