LDL Cholesterol, Serum/Plasma — Substance Concentration
This blood test measures low-density lipoprotein (LDL) cholesterol, a substance that transports cholesterol in the blood and can contribute to plaque buildup in arteries.
["LDL cholesterol is one part of cholesterol testing and is commonly used to help assess cardiovascular risk."]
Key facts at a glance
- LOINC
- 56136-5
- Short code
- LDL1 SerPl-sCnc
- Synonyms
- LDL1 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?
This test measures the concentration of LDL cholesterol in serum or plasma. LDL is often called “bad” cholesterol because high levels can promote cholesterol buildup in artery walls.
Why might I need this test?
LDL measurement is commonly part of a lipid panel used to evaluate heart disease and stroke risk. It may also be checked to monitor cholesterol-lowering treatment or a diet aimed at improving cholesterol levels.
How is the test performed?
A blood sample is collected, usually by a venous blood draw. The laboratory separates the serum or plasma and measures LDL cholesterol using a validated biochemical method.
How do I prepare for the test?
Fasting for about 9 to 12 hours may be recommended, especially when the test is ordered with other cholesterol measurements. Water is generally allowed, but follow the specific instructions provided by your healthcare professional.
Reference range
Optimal: <100 mg/dLN/A
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.
A higher LDL cholesterol concentration can indicate increased cardiovascular risk, particularly when other risk factors are present. Results should be interpreted with total cholesterol, HDL cholesterol, triglycerides, medical history, and other risk factors because an LDL value alone does not determine a diagnosis or treatment plan.
Short name
LDL Cholesterol
Frequently asked questions
Is LDL cholesterol the same as total cholesterol?
Do I need to fast before this test?
Can diet and medicines change LDL cholesterol?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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