Glucagon, Plasma
Use
This test is useful for the diagnosis and follow-up of glucagonomas and other glucagon-producing tumors. It is also used for assessing diabetic patients with problematic hyper- or hypoglycemic episodes, though the utility in this context is extremely limited. Glucagon secretion is crucial in the regulation of blood glucose levels, particularly during hypoglycemia. Inappropriately high levels can complicate conditions like diabetes, especially during ketoacidosis, and may also indicate the presence of glucagon-secreting tumors.
Special Instructions
Patients undergoing this test must fast for at least 8 hours prior to specimen collection. It is important to use a lavender top (EDTA) tube, pre-chilled at 4 degrees C, to collect the specimen. Fill the tube with blood and maintain it in wet ice for 10 minutes before centrifugation in a refrigerated centrifuge. Once separated, the plasma should be immediately aliquoted into a plastic vial and frozen. If not ordering electronically, complete and send the Oncology Test Request form (T729) with the specimen.
Limitations
The test results can vary depending on the glucagon assay used. Different assays may have different calibration standards or cross-reactivity with various glucagon isoforms, not all of which are biologically active. It's crucial for serial measurements to be performed using the same assay to ensure consistency. Also, heterophile antibody interference or human anti-mouse antibodies can affect results, leading to false readings. Additionally, this test, like other tumor markers, is not specific for malignancy. Therefore, unexpected results should be reviewed carefully, considering possible assay interferences.
FDA ApprovedNew York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 2338-2
- 2338-2
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
2 mL
Minimum Volume
0.45 mL
Container
Plastic vial
Collection Instructions
Pre-chill lavender top (EDTA) tube at 4 degrees C before collecting the specimen. Draw blood into the pre-chilled tube and process as follows: chill filled tube in wet ice for 10 minutes, centrifuge in a refrigerated centrifuge or a pre-chilled centrifuge carrier, then aliquot plasma into a plastic vial and freeze immediately.
Patient Preparation
Fasting: 8 hours, required
Causes for Rejection
Gross hemolysis, gross lipemia, gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 90 days |