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Low-Density Lipoprotein Cholesterol (LDL-C), Calculated, Serum/Plasma — Substance Concentration

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

Measures LDL cholesterol in blood, often calculated from other lipid values, to help assess cardiovascular risk and guide cholesterol management.

Quick summary

["This test helps estimate the amount of LDL, or “bad,” cholesterol in your blood and is commonly used to assess heart disease risk."]

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

Key facts at a glance

LOINC
56138-1
Short code
LDL3 SerPl-sCnc
Synonyms
LDL3 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?

Low-density lipoprotein cholesterol (LDL-C) is a type of cholesterol carried in the blood. This test commonly calculates LDL-C from the results of a cholesterol panel, including total cholesterol, HDL cholesterol, and triglycerides.

Why might I need this test?

LDL-C is used to help estimate your risk of heart attack, stroke, and other cardiovascular problems. It may also be used to monitor the effects of diet, physical activity, and cholesterol-lowering treatment.

How is the test performed?

A blood sample is drawn and analyzed as part of a lipid panel. In many laboratories, the LDL-C result is calculated using the other values in that panel; some laboratories can also measure LDL-C directly.

How do I prepare for the test?

Fasting is often not required, but your clinician or laboratory may request a fasting sample, particularly when triglycerides are elevated or other lipid tests are being checked. Follow the laboratory's instructions and avoid heavy eating and alcohol for the recommended period if fasting is required.

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

Calculated LDL Cholesterol

Frequently asked questions

Is this the same as “bad cholesterol”?
Yes. LDL-C is commonly called “bad cholesterol” because it can contribute to plaque buildup in arteries.
Do I need to fast before this test?
Not always. A lipid panel may be performed without fasting, but fasting may be recommended when triglycerides are elevated or when the laboratory specifically requests it.
Can calculated LDL-C be used to monitor treatment?
Yes. Repeat lipid panels can show how LDL-C responds to lifestyle changes or cholesterol-lowering medication. Direct LDL-C measurement may be considered in certain situations, such as when standard calculated results are not appropriate.
  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