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Intermediate-Density Lipoprotein (IDL) Cholesterol, Serum/Plasma — Substance Concentration

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

Measures cholesterol carried in intermediate-density lipoprotein particles, which are a type of remnant cholesterol. It is often included with an advanced lipid profile.

Quick summary

["IDL cholesterol helps assess one type of circulating cholesterol, usually alongside the rest of your lipid profile."]

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

Key facts at a glance

LOINC
56134-0
Short code
IDL1c SerPl-sCnc
Synonyms
IDL1c 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 blood test measures the amount of cholesterol in intermediate-density lipoprotein, or IDL. IDL particles form when cholesterol-rich remnants from triglyceride metabolism circulate in the blood.

Why might I need this test?

IDL cholesterol may be included in an advanced lipid profile to help evaluate cardiovascular risk, especially when standard cholesterol results need additional context. Your clinician may also order it when researching unusually high or low levels of other lipids.

How is the test performed?

A blood sample is collected, and the serum or plasma portion is analyzed. Depending on the laboratory, IDL cholesterol may be measured directly or calculated from other results in the lipid panel.

How do I prepare for the test?

Follow the laboratory's instructions about fasting. Fasting may be requested for the complete lipid panel, so avoid eating for the specified period if told to do so, and tell the laboratory if you have recently eaten.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IDL cholesterol

Frequently asked questions

Is IDL the same as LDL cholesterol?
No. IDL and LDL are different classes of cholesterol-carrying particles. IDL particles are denser than VLDL but less dense than LDL.
Does this test require fasting?
It depends on the laboratory and the other tests being performed. A lipid panel is often fasting, so follow any preparation instructions provided when the test is ordered.
What does a high IDL cholesterol result mean?
A high result may indicate increased circulating remnant cholesterol. Your clinician will consider it together with your other lipid results, cardiovascular risk factors, and medical history.
  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