Proinsulin, Intact/Insulin Ratio
Also known as: PRO INS
Use
Aids in the detection of insulinoma by measuring the ratio of proinsulin to intact insulin. It is important for the assessment of patients suspected of having an insulinoma, which is a typically benign tumor of the pancreas that can cause excessive insulin production, leading to symptoms of hypoglycemia. This test provides critical information for diagnosis but is not intended for diagnosing diabetes mellitus.
Special Instructions
Patient must be fasting for 10-12 hours prior to collection. Use serum separator tube (SST) for collection. Transfer 1 mL serum to an ARUP standard transport tube and freeze immediately. Maintain specimens in a critical frozen state. Separate, untreated specimens are needed for multiple tests ordered concurrently.
Limitations
Heparinized plasma, vitreous and I.V. fluids, and hemolyzed specimens are unacceptable for testing. The test reactions vary with different insulin analogs; insulin detemir shows about 50 percent cross-reactivity, and glulisine has negligible reaction. Environmental and handling conditions such as repeated freeze/thaw cycles may affect test accuracy. This test is specifically structured for insulinoma evaluation and may not cover other insulin-related disorders.
New York Approved
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 10451-3
- 27873-9
- 45338-1
- 27873-9
- 10451-3
- 45338-1
Result Turnaround Time
1-6 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.8 mL
Container
ARUP standard transport tube
Collection Instructions
Use serum separator tube (SST). Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP standard transport tube and freeze immediately.
Patient Preparation
Fasting for 10-12 hours prior to collection.
Storage Instructions
CRITICAL FROZEN.
Causes for Rejection
Heparinized plasma. Vitreous or I.V. fluids. Hemolyzed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 24 hours |
| Frozen | 2 months (avoid repeated freeze/thaw cycles) |
Other tests from different labs that may be relevant