Insulinoma laboratory tests: Difference between revisions
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==Various Tests== | ==Various Tests== | ||
===Lab Tests=== | ===Lab Tests=== | ||
The diagnosis of insulinoma is suspected in a patient with symptomatic fasting hypoglycemia. The conditions of [[Whipple’s triad]] need to be met for the diagnosis of "true hypoglycemia" to be made:< | The diagnosis of insulinoma is suspected in a patient with symptomatic fasting hypoglycemia. The conditions of [[Whipple’s triad]] need to be met for the diagnosis of "true hypoglycemia" to be made:<ref name="pmid23430217">{{cite journal| author=Okabayashi T, Shima Y, Sumiyoshi T, Kozuki A, Ito S, Ogawa Y et al.| title=Diagnosis and management of insulinoma. | journal=World J Gastroenterol | year= 2013 | volume= 19 | issue= 6 | pages= 829-37 | pmid=23430217 | doi=10.3748/wjg.v19.i6.829 | pmc=PMC3574879 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23430217 }} </ref> | ||
:1. Hypoglycemia(plasma glucose < 50 mg/dL) | |||
: | :2. Neuroglycopenic symptoms | ||
:3. | :3. Reversibility of symptoms with administration of glucose | ||
===Blood tests=== | ===Blood tests=== | ||
Revision as of 14:47, 5 October 2015
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Parminder Dhingra, M.D. [2]
Overview
Various Tests
Lab Tests
The diagnosis of insulinoma is suspected in a patient with symptomatic fasting hypoglycemia. The conditions of Whipple’s triad need to be met for the diagnosis of "true hypoglycemia" to be made:[1]
- 1. Hypoglycemia(plasma glucose < 50 mg/dL)
- 2. Neuroglycopenic symptoms
- 3. Reversibility of symptoms with administration of glucose
Blood tests
The following blood tests are needed to diagnose insulinoma:
- glucose
- insulin
- C-peptide
If available, a proinsulin level might be useful as well. Other blood tests may help rule out other conditions which can cause hypoglycemia.
Suppression tests
Normally, endogenous insulin production is suppressed in the setting of hypoglycemia. A 72-hour fast, usually supervised in a hospital setting, can be done to see if insulin levels fail to suppress, which is a strong indicator of the presence of an insulin-secreting tumour.
- During the test, the patient may have calorie-free and caffeine-free liquids. Capillary blood glucose is measured every 4 hours using a reflectance meter, until values < 60 mg/dL (3.3 mmol/L) are obtained. Then, the frequency of blood glucose measurement is increased to every hour until values are < 49 mg/dL (2.7 mmol/L). At that point, or when the patient has symptoms of hypoglycemia, a blood test is drawn for serum glucose, insulin, proinsulin, and C-peptide levels. The fast is stopped at that point, and the hypoglycemia treated with intravenous dextrose or calorie-containing food or drink.
References
- ↑ Okabayashi T, Shima Y, Sumiyoshi T, Kozuki A, Ito S, Ogawa Y; et al. (2013). "Diagnosis and management of insulinoma". World J Gastroenterol. 19 (6): 829–37. doi:10.3748/wjg.v19.i6.829. PMC 3574879. PMID 23430217.