Proinsulin, Plasma
Use
The Proinsulin, Plasma test is useful in the diagnostic workup of conditions such as insulinoma, prohormone convertase 1/3 deficiency, and proinsulin variations. In suspected insulinomas, it aids in demonstrating nonsuppressed insulin levels in the presence of hypoglycemia. It also helps in identifying elevated proinsulin levels which are common in patients with insulin-producing islet cell tumors, potentially leading to hypoglycemic attacks. Elevated proinsulin can also indicate conditions such as type 2 diabetes or insulin resistance.
Special Instructions
Patients are required to fast for 8 hours before the test. Infants under 2 years should fast for a maximum of 6 hours. Collection of specimens should be done using ice-cooled lavender top (EDTA) tubes, and plasma should be aliquoted into plastic vials and sent frozen.
Limitations
Proinsulin measurements must be interpreted considering coexisting illnesses, blood glucose concentration at sample time, and other related tests such as insulin and C-peptide measurements. Patients with chronic kidney failure or type 2 diabetes mellitus may show increased proinsulin levels without suppressed blood glucose concentrations, which can cause diagnostic confusion.
New York Approved
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 27882-0
- 27882-0
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.5 mL
Minimum Volume
0.25 mL
Container
Plastic vial
Collection Instructions
After collection, place the whole blood on ice for at least 10 minutes, then centrifuge at refrigerated temperature. Aliquot plasma into a plastic vial and send frozen.
Patient Preparation
Fasting: 8 hours required; infants under 2 years should fast a maximum of 6 hours.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 30 days |