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Serum Cholesterol (Total)

Published: August 9, 2026Updated: August 17, 2026

This test measures the total amount of cholesterol in your blood, which includes both low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol. Cholesterol is a type of fat that your body needs to function properly, but having too much can increase your risk of heart disease.

Quick summary

["Cholesterol levels help assess your heart health risk and guide treatment plans for managing blood fat levels."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
102247-4
Short code
Codfish IgE RAST
Synonyms
Codfish IgE RAST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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 Cholesterol Matters

Cholesterol is an essential substance your body uses for cell membranes, hormone production, and vitamin D synthesis. However, high cholesterol levels can build up in your arteries, restricting blood flow and increasing the risk of heart disease or stroke. This test helps doctors monitor your cholesterol status and recommend lifestyle or medical interventions if needed.

What to Expect Before the Test

No special preparation is required for this test. You may have a blood sample drawn from a vein in your arm, typically during a routine office visit or lab visit. If you’re fasting, your doctor may instruct you to avoid eating or drinking anything except water for 12 hours before the test to get a more accurate reading of your cholesterol levels.

How the Test Works

Blood is collected and sent to a lab, where it is analyzed to measure the total cholesterol concentration. The test does not differentiate between HDL and LDL cholesterol at this stage, though these are often measured separately in full lipid panels.

What Your Results Mean

Results are typically reported as a single number representing total cholesterol. While specific reference ranges vary by lab, higher-than-normal levels may signal the need for further evaluation or lifestyle changes to improve heart health.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Cholesterol

Frequently asked questions

What causes high cholesterol?
High cholesterol can result from a combination of factors, including genetics, diet high in saturated or trans fats, lack of physical activity, obesity, and certain medical conditions like diabetes or thyroid disorders. Lifestyle choices, such as eating a balanced diet and exercising regularly, can help lower cholesterol levels.
What if my cholesterol is high?
If your cholesterol test results show high levels, your healthcare provider may recommend dietary changes (such as reducing saturated fats), increased physical activity, or medications like statins to help lower cholesterol. Follow-up tests may also be scheduled to monitor progress.
How often should I get this test?
The frequency of cholesterol testing depends on your age, overall health, and risk factors. Typically, adults with no known risk factors may get tested every 4–6 years, while those with risk factors (like high blood pressure or a family history of heart disease) may need testing more often, often every 1–2 years.
  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 17, 2026. · Read our editorial policy