Free Erythrocyte Cholesterol (FEC) from Whole Blood, Measured by Electrochemiluminescence
This test measures the amount of cholesterol found in red blood cells, specifically the free (unesterified) form. It may be used to assess lipid metabolism or identify conditions affecting red blood cell cholesterol.
["Understanding your red blood cell cholesterol levels can help identify potential health risks."]
Key facts at a glance
- LOINC
- 33159-5
- Short code
- Fet CRL from GA.ASUM00
- Synonyms
- Fet CRL from GA.ASUM00
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-estimated-from-asum
- 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 Might Be Ordered
Your healthcare provider may recommend this test if they suspect conditions like hereditary erythropoietic porphyria, certain metabolic disorders, or if you have a family history of red blood cell-related lipid abnormalities. It could also be part of a broader evaluation for unexplained symptoms like fatigue, anemia, or skin changes.
What to Expect Before the Test
No special preparation is typically needed. You may have a small needle inserted into your arm to draw a blood sample. If you’re nervous, let your healthcare provider know—they can offer ways to make it more comfortable.
What the Test Results Mean
This test measures the concentration of free cholesterol in your red blood cells. While reference ranges vary by lab, abnormal results may signal conditions affecting red blood cell lipid metabolism. Your provider will discuss findings in the context of your overall health.
Common Conditions Linked to FEC Testing
Elevated or low FEC levels can be associated with hereditary disorders, metabolic syndromes, or conditions affecting red blood cell structure. For example, certain porphyrias or lipid storage disorders may show distinct patterns in red blood cell cholesterol.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical significance of FEC includes identifying hereditary lipid disorders, evaluating red blood cell membrane stability, and supporting diagnoses in conditions where red blood cells play a key role in metabolic or structural dysfunction.
Short name
FEC (Whole Blood)
Frequently asked questions
What does a high or low FEC result mean?
How often should I get this test?
Can lifestyle changes affect FEC results?
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