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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 in your blood, a type of fat that can build up in your arteries and increase your risk of heart disease.

Quick summary

["LDL cholesterol is a key measure of heart health; higher levels may raise your risk of cardiovascular issues."]

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

Key facts at a glance

LOINC
17846-7
Short code
LDL SerPl Ql
Synonyms
LDL SerPl Ql
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 it can contribute to plaque buildup in your arteries. High levels may increase your risk of heart attack or stroke, so monitoring it is important for long-term heart health.

What to Expect Before the Test

You’ll typically have a simple blood draw from a vein in your arm. No special preparation is needed, but fasting (not eating or drinking) for 9–12 hours before the test may be required, depending on your doctor’s instructions.

How the Results Are Used

Your doctor will use these results to assess your overall cholesterol profile and help determine if lifestyle changes, medications, or other treatments are needed to manage your heart health.

Common Causes of High LDL Cholesterol

High LDL cholesterol can result from genetics, poor diet (high in saturated fats), lack of physical activity, obesity, smoking, or certain medical conditions like diabetes or hypothyroidism.

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.

Elevated LDL cholesterol is a major risk factor for atherosclerosis (plaque buildup in arteries), which can lead to serious cardiovascular events. Regular monitoring helps doctors identify and manage risk early to prevent complications.

Short name

LDL Cholesterol

Frequently asked questions

What does an elevated LDL cholesterol level mean?
An elevated LDL cholesterol level suggests your body may be producing too much or your liver isn’t removing it efficiently. This can increase your risk of artery damage over time, so your doctor may recommend lifestyle changes or medications to lower it.
What if my LDL cholesterol is within the normal range?
Even if your LDL cholesterol is normal, your doctor may still monitor other cholesterol types (like HDL or triglycerides) or recommend lifestyle adjustments to support heart health, as risk factors like diet, exercise, and smoking habits also play a role.
Can diet or exercise lower my LDL cholesterol?
Yes! Diet changes (e.g., reducing saturated fats, increasing fiber), regular exercise, and quitting smoking can help lower LDL cholesterol naturally. Your doctor may also prescribe medications if lifestyle changes aren’t enough.
  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