Serum Insulin — Exclusion-Criteria Entry (PhenX)
This entry appears to refer to insulin measured in serum. “Exclusion criteria” and “PhenX” are not standard parts of a routine insulin test and may identify a special protocol.
["The test measures insulin in a blood sample, but the special exclusion-criteria qualifier may affect how the result should be used."]
Key facts at a glance
- LOINC
- 66505-9
- Short code
- Exclusion criteria serum insulin PhenX
- Synonyms
- Exclusion criteria serum insulin PhenX
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 2.6
- Ref high
- 24.9
- Fasting
- true
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- phenx
- CPT
- 83525
- SNOMED
- 413618004
- 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
What is this test?
This test measures the amount of insulin in serum, the liquid portion of blood. Insulin is a hormone that helps the body regulate blood sugar by moving glucose into cells and encouraging energy storage.
Why might I need this test?
A serum insulin test may be ordered to help assess how the body is handling glucose. It can be used in the evaluation of low or high blood sugar, insulin resistance, diabetes, or conditions involving insulin production, depending on the clinical situation.
How is the test performed?
Blood is collected through a vein, and the serum is separated from the clotted sample. The insulin level is then measured using a laboratory method. The “PhenX” qualifier in this entry is not clearly defined and should be confirmed with the ordering laboratory.
How do I prepare for the test?
Follow the preparation instructions provided by your clinician or laboratory. The test may be performed while fasting or at a specified time, and insulin levels can be affected by meals and glucose intake. Do not change medications or restrict food unless your clinician directs you to do so.
Reference range
Fasting: 2.6-24.9 μIU/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An insulin result is interpreted together with the blood glucose level, timing of the sample, symptoms, medications, and other laboratory findings. Insulin that is higher or lower than expected may reflect fasting, food intake, diabetes or insulin resistance, medication effects, or less common disorders of insulin production or action. The term “exclusion criteria” may mean that this result is being used in a specific decision rule, so the result should not be interpreted independently without that context.
Short name
Serum insulin
Frequently asked questions
Is this the same as a routine insulin blood test?
Do I need to fast before this test?
Can a serum insulin result diagnose diabetes?
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