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Low-Density Lipoprotein Cholesterol (LDL-C) in Serum

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

This test measures the amount of LDL cholesterol, a type of fat in your blood that can build up in your arteries over time.

Quick summary

["LDL cholesterol is important for managing heart health and preventing artery blockages."]

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

Key facts at a glance

LOINC
54434-6
Short code
LDL SerPl-sCnc
Synonyms
LDL SerPl-sCnc
Category
chemistry
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

This test measures the level of low-density lipoprotein (LDL) cholesterol in your blood. Your doctor orders it to evaluate your risk of heart disease and stroke, to monitor how well your cholesterol treatment is working, and to help decide whether you need lifestyle changes or medication.

Your healthcare provider may order an LDL cholesterol test to check your risk of heart disease, stroke, or other cardiovascular problems. It’s often part of a broader lipid panel that also includes tests for HDL cholesterol and total cholesterol.

A high LDL level means excess cholesterol can build up on the walls of your arteries, narrowing them and raising your risk of heart attack and stroke. A low or normal LDL level lowers that risk and usually shows that your prevention plan is working. Your doctor will read your result together with your other risk factors, since very low levels are rarely a concern.

High LDL cholesterol levels may increase your risk of artery blockages, which can lead to heart attacks or strokes. Low levels are generally less concerning unless other health conditions are present.

A trained health professional draws a small sample of blood from a vein in your arm, usually on the inside of the elbow or the back of the hand. The sample goes to a laboratory, where the LDL cholesterol level is measured and reported in mg/dL. The draw takes only a few minutes, and you may feel a quick pinch or brief soreness at the site.

A blood sample is taken from a vein, usually in your arm. The blood is then processed to separate serum (the liquid part after clotting) for testing.

Your care team may ask you to fast for 9 to 12 hours before the blood draw, taking nothing but water, although many lipid panels today do not require fasting. Tell your doctor about every prescription drug, vitamin, and supplement you use, because some of them can change your results, and follow any other instructions you are given.

Follow your healthcare provider’s instructions, which may include fasting for 8–12 hours before the test to get more accurate results.

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.

Clinical Significance: LDL Cholesterol and Heart Health

Short name

LDL Cholesterol

Frequently asked questions

LDL cholesterol is often called the 'bad' cholesterol because it tends to stick to artery walls, forming plaques that can restrict blood flow and increase the risk of heart disease.
Most healthy adults should have their LDL cholesterol checked every 4 to 6 years as part of routine care. You may need testing more often, such as once or twice a year, if you have high cholesterol, heart disease, diabetes, a family history of early heart disease, or if you are starting or changing cholesterol medicine.
Your healthcare provider will determine how often you need this test based on your overall health, risk factors, and medical history. Regular check-ups are important to monitor your cholesterol levels over time.
For most adults, an LDL level below 100 mg/dL is considered optimal, 100 to 129 mg/dL is near optimal, and 130 to 159 mg/dL is borderline high, while 160 mg/dL or above is high and 190 mg/dL or higher is very high. Your personal target may differ, so always review your result with your doctor.
There is no single 'normal' range for LDL cholesterol because it varies by individual health needs. Your results will be compared to your personal baseline and risk profile.
Yes! Eating a heart-healthy diet (low in saturated fats and cholesterol), exercising regularly, and maintaining a healthy weight can help lower LDL cholesterol levels.
  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