|
|
Lab Dept:
|
Chemistry
|
Test Name:
|
PROINSULIN, PLASMA
|
General Information
|
Lab Order Codes:
|
PROIN
|
Synonyms:
|
Insulinoma
|
CPT Codes:
|
84206 - Proinsulin
|
Test Includes:
|
Proinsulin level reported in pmol/L.
|
Logistics
|
Test Indications:
|
As part of the diagnostic workup of suspected insulinoma, PC1/3 deficiency, or with suspected proinsulin mutations.
|
Lab Testing Sections:
|
Chemistry - Sendouts
|
Referred to:
|
Mayo Medical Laboratories (MML Test #: PINS/80908)
|
Phone Numbers:
Minneapolis:
Saint Paul:
|
|
612-813-6280
|
651-220-6550
|
Test Availability:
|
Daily, 24 hours
|
Turnaround Time:
|
2 – 7 days, performed Monday and Thursday
|
Special Instructions:
|
See special container, collection procedure and patient preparation.
|
Specimen
|
Specimen Type:
|
Blood
|
Container:
|
Ice cooled Lavender top (EDTA) tube
|
Draw Volume:
|
4.5 mL (Minimum: 2 mL) blood
|
Processed Volume:
|
1.5 mL (Minimum: 0.65 mL) plasma
|
Collection:
|
Routine venipuncture. Draw blood into an ice cooled lavender top tube from a fasting patient. After draw, chill the whole blood on ice for at least 10 minutes before processing.
|
Special Processing:
|
Lab Staff: Centrifuge specimen after the specimen has been on ice for at least 10 minutes in a refrigerated centrifuge. Remove plasma into a screw-capped plastic vial. Store and ship and frozen temperatures.
|
Patient Preparation:
|
Fasting specimen preferred
|
Sample Rejection:
|
Marked hemolysis; marked lipemia; warm specimens <2 hours; mislabeled or unlabeled specimens
|
Interpretive
|
Reference Range:
|
3 – 20 pmol/L
|
Critical Values:
|
N/A
|
Limitations:
|
To avoid misdiagnosis, all proinsulin measurements used in the diagnostic workup of patients with hypoglycemia must be interpreted in the context of coexisting illnesses, the blood glucose concentration at the time of sampling, and other test results (ie, insulin, C-peptide, beta-hydroxybutyrate, and sulfonylurea drug screen). For example, patients with chronic renal failure or type 2 diabetes mellitus can have increased proinsulin, C-peptide and insulin values, but usually without suppressed (<45 g/dL) blood glucose.
|
Methodology:
|
Immunochemiluminescent Assay
|
References:
|
Mayo Medical Laboratories Web Page September 2012
|
