Skip to content

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

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

This test measures the amount of LDL cholesterol, a type of fat (lipid) in your blood that can build up in your arteries over time, increasing the risk of heart disease.

Quick summary

["LDL cholesterol is a key marker for heart health and risk of artery blockages."]

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

Key facts at a glance

LOINC
47215-9
Short code
LDL med SerPl Qn
Synonyms
LDL med SerPl Qn
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

Why This Test Matters

LDL cholesterol is often called the 'bad' cholesterol because high levels can contribute to plaque buildup in your arteries, which may restrict blood flow and increase the risk of heart attack or stroke. This test helps healthcare providers assess your cardiovascular risk and guide treatment plans.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw from a vein in your arm. If you’re fasting, your provider will advise you beforehand. Avoid smoking or consuming alcohol for a few hours before the test if instructed.

How the Test Works

Blood is drawn and sent to a lab where it is analyzed using an immunoassay method to measure LDL cholesterol levels. The results help determine your overall cholesterol profile and cardiovascular health.

Common Reasons for Testing

Your healthcare provider may order this test if you have risk factors for heart disease (such as high blood pressure, diabetes, or a family history of heart problems), if you’ve had a heart attack or stroke, or as part of routine cholesterol screening.

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

Short name

LDL Cholesterol

Frequently asked questions

How does LDL cholesterol relate to heart disease?
High LDL cholesterol levels increase the risk of plaque formation in your arteries, which can lead to narrowed or blocked arteries. This can restrict blood flow and increase the likelihood of heart attacks or strokes. Your provider may recommend lifestyle changes or medications to lower LDL if levels are elevated.
What if my LDL cholesterol is high?
If your LDL cholesterol is high, your healthcare provider may suggest dietary changes (such as reducing saturated fats), exercise, or medications like statins to help lower it. Follow-up tests may be scheduled to monitor progress.
Can LDL cholesterol be lowered naturally?
Yes, several lifestyle changes can help lower LDL cholesterol naturally, including eating a heart-healthy diet (rich in fruits, vegetables, and whole grains), exercising regularly, maintaining a healthy weight, and avoiding smoking.
  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