Proinsulin-to-Insulin Ratio, Serum/Plasma
Measures the balance of proinsulin, an insulin precursor, to mature insulin in blood to help evaluate pancreatic insulin production.
["An altered proinsulin-to-insulin ratio may reflect impaired insulin processing or insulin resistance."]
Key facts at a glance
- LOINC
- 45338-1
- Short code
- Proinsulin/Insulin SerPl-Rto
- Synonyms
- Proinsulin/Insulin SerPl-Rto
- Category
- hormone
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 2.6
- Ref high
- 24.9
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 blood test compares the amount of proinsulin with the amount of mature insulin. Proinsulin is made by the pancreas and then processed into insulin, so the ratio can provide information about how the body is producing and handling insulin.
Why might I need this test?
A clinician may order this test when evaluating diabetes, insulin resistance, or unusual insulin levels. It may also be used in specialized assessments of pancreatic function or symptoms related to abnormal insulin production.
How is the test performed?
A blood sample is collected, and the laboratory measures proinsulin and insulin in the serum or plasma using validated laboratory methods. The results are then used to calculate their ratio.
How do I prepare for the test?
Fasting may be required depending on the laboratory's instructions and the reason for testing. Tell your clinician about insulin injections and other diabetes medicines, but do not stop or change any medication without medical guidance.
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.
A higher proinsulin-to-insulin ratio may occur when the pancreas releases more proinsulin than is efficiently converted into mature insulin, which can be associated with insulin resistance or type 2 diabetes. The ratio can also be affected by kidney disease, pancreatic conditions, medications, and laboratory factors, so results should be interpreted with the other parts of the medical evaluation.
Short name
Proinsulin/Insulin Ratio
Frequently asked questions
What does a high proinsulin-to-insulin ratio mean?
Is this the same as an insulin test?
Do I need to stop my diabetes medication before this test?
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