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Peptide fragment analysis of proinsulin (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the breakdown products of proinsulin, a precursor hormone involved in blood sugar regulation. It helps assess insulin production and function.

Quick summary

["This test may help diagnose or monitor conditions affecting insulin processing."]

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

Key facts at a glance

LOINC
108144-7
Short code
C peptide sp1 SerPl-mCnc
Synonyms
C peptide sp1 SerPl-mCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85610
SNOMED
396252006
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 Is Done

Your doctor may order this test if they suspect issues with insulin production, such as type 1 or type 2 diabetes, or if you have symptoms like unexplained weight changes, fatigue, or abnormal blood sugar levels. It can also be part of routine monitoring for people with diabetes.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if instructed by your healthcare provider. Bring any medications you’re currently taking to your appointment.

How the Test Is Performed

A blood sample is drawn from a vein, typically in your arm, using a small needle. You may feel a slight pinch, but it usually doesn’t cause significant discomfort. The sample is sent to a lab for analysis using a specialized method to detect peptide fragments of proinsulin.

What the Results Mean

Abnormal results may indicate problems with insulin processing, such as diabetes, pancreatic issues, or other metabolic disorders. Your doctor will interpret the results in the context of your medical history and other test results.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: serum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Proinsulin Peptide Levels

Frequently asked questions

What questions might you have?
This test is primarily used to evaluate insulin metabolism and may help diagnose conditions like diabetes or insulin-related disorders. It’s not a routine screening test but is often included in specialized evaluations.
How often should I get this test?
The frequency depends on your health condition. If you have diabetes or a related disorder, your doctor may recommend testing as part of your ongoing management plan, possibly every few months or annually.
Can fasting affect this test?
Yes, fasting may influence proinsulin levels. If fasting is required, follow your doctor’s instructions to ensure accurate results.
  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