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Test Code GLUCG Glucagon, Plasma

Reporting Name

Glucagon, P

Useful For

Diagnosis and follow-up of glucagonomas and other glucagon-producing tumors

 

Assessing diabetic patients with problematic hyper- or hypoglycemic episodes (extremely limited utility)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Plasma EDTA


Specimen Required


Patient Preparation: Fasting (8 hours)

Supplies: Aliquot Tube, 5 mL (T465)

Collection Container/Tube: Lavender top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: 2 mL

Collection Instructions:

1. Pre-chill tube at 4° C before drawing the specimen.

2. Draw into the pre-chilled tube, and process as follows:

a. After drawing specimen, chill tube in wet ice for 10 minutes.

b. Centrifuge in a refrigerated centrifuge or in chilled centrifuge carrier.

c. Immediately after centrifugation, aliquot plasma into a plastic vial, and freeze.


Specimen Minimum Volume

0.45 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma EDTA Frozen 90 days

Reference Values

≤6 hours: 100-650 pg/mL

1-2 days: 70-450 pg/mL

2-4 days: 100-650 pg/mL

4-14 days: declining gradually to adult levels

>14 days: ≤80 pg/mL (range based on 95% confidence limits)

 

Glucagon levels are inversely related to blood glucose levels at all ages. This is particularly pronounced at birth and shortly thereafter, until regular feeding patterns are established. This explains the higher levels immediately after birth, which then first fall as the glucagon release mobilizes the infant's glucose stores, then rise again as stores are depleted, finally normalizing towards adult levels as regular feeding patterns are established.

 

For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Day(s) and Time(s) Performed

Thursday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82943

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GLP Glucagon, P 2338-2

 

Result ID Test Result Name Result LOINC Value
9358 Glucagon, P 2338-2

Clinical Reference

1. Tomassetti P, Migliori M, Lalli S, et al: Epidemiology, clinical features and diagnosis of gastroenteropancreatic endocrine tumours. Ann Oncol. 2001;12 Suppl 2:S95-99

2. Jhiang G, Zhang BB: Glucagon and regulation of glucose metabolism. Am J Physiol Metab. 2003;284:E671-E678

3. vanBeek AP, de Haas ER, van Vloten WA, et al: The glucagonoma syndrome and necrolytic migratory erythema: a clinical review. Eu J Endocrinol. 2004;151:531-537

4. Cruz-Bautista I, Lerman I, Perez-Enriquez B, et al: Diagnostic challenge of glucagonoma: case report and literature review. Endocr Pract. 2006 Jul-Aug;12(4):422-426

5. Falconi M, Eriksson B, Kaltsas G, et al: ENETS Consensus guidelines update for the management of patients with functional pancreatic neuroendocrine tumors and non-functional pancreatic neuroendocrine tumors. Neuroendocrinology. 2016;103(2):2153-2171

Method Description

Big plasma glucagon (BPG), which is considered to be biologically inactive, is extracted using ethanol prior to assay of the specimen. Following ethanol extraction, glucagon reacts with an anti-glucagon antibody that is attached to magnetic beads. After incubation and washing, a second detection antibody is added and attaches to any bead-bound glucagon, forming a sandwich assay. A streptavidin-phycoerythrin (SPE) tag binds to the glucagon-antibody complex. Laser-based fluorescent analysis of the resulting glucagon-antibody-SPE complex is performed on the Luminex 200 instrument.(Package insert: Human Glucagon Magnetic Bead Kit, Millipore Sigma; Rev. 12/26/2018)

Analytic Time

2 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Method Name

Immunoassay