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LDL Cholesterol Calculated, Serum/Plasma — Substance Concentration

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

A blood test that measures low-density lipoprotein (LDL) cholesterol, often calculated from total cholesterol, HDL cholesterol, and triglycerides to help assess cardiovascular risk.

Quick summary

["LDL cholesterol helps estimate the buildup of cholesterol in artery walls 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
91114-9
Short code
LDL3c SerPl-sCnc
Synonyms
LDL3c SerPl-sCnc
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?

LDL cholesterol is a type of cholesterol that circulates in the blood. This test may be measured directly or calculated from other lipid values. It is used as part of assessing cardiovascular risk.

Why might I need this test?

Your clinician may order this test during a lipid panel, for a routine health check, or to monitor cholesterol-lowering treatment. It can help guide lifestyle changes or medication decisions.

How is the test performed?

A blood sample is drawn from a vein and analyzed in the laboratory. The report may identify the result as calculated or direct, depending on the laboratory method used.

How do I prepare for the test?

Follow your clinician's instructions about fasting. Some lipid tests are more accurate after an overnight fast, while others may not require fasting. Tell your clinician if you are taking cholesterol-lowering medicines or if you have recently changed your diet.

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 cholesterol is commonly called “bad” cholesterol because it can contribute to cholesterol deposits in artery walls. HDL cholesterol is often called “good” cholesterol and has different functions in the body.
Does this test require fasting?
Fasting may be requested, especially when triglycerides are also being measured, but requirements vary by laboratory and clinical situation. Follow the specific instructions provided with the test order.
What can I do if my LDL cholesterol is high?
Your clinician may review diet, physical activity, weight, smoking, and other risk factors. Depending on your overall cardiovascular risk, treatment may include lifestyle changes and/or cholesterol-lowering medication.
  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