Days Set Up
Monday - Friday
Analytic Time

9 - 11 days

MiChart Code
Soft Order Code

Test Updated:


Somatotropin Release Inhibiting Factor

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Test Overview

Test Methodology


Test Usage

Somatostatin is a cyclic peptide originally isolated from sheep hypothalami and shown to inhibit the release of Growth Hormone. Somatostatin is present primarily in three main forms: a 14 amino acid peptide, a 28 amino acid peptide ("Big" Somatostatin), and a 12,000 molecular weight ProSomatostatin. This assay measures only the 14 amino acid form of Somatostatin. All three forms of Somatostatin have similar biological properties and overall potencies. Somatostatin is a physiological regulator of Islet Cell and gastrointestinal functions, and is a suppressor of many pituitary hormones including Growth Hormone, Prolactin, and Thyrotropin (TSH). Somatostatin levels are often elevated in diabetics, but the levels return to normal upon correction of the hormonal and metabolic deficiencies present. In many cases of APUDomas including VIPoma, Insulinoma, Glucagonoma, and Gastrinoma, elevated levels of Somatostatin are found.

Reference Range

< 25 pg/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Offsite

Collect specimen in "G.I. Preservative" tube (red top with preservative), available from MLabs. For baseline determination collect specimen following an overnight (10-12 hour) fast. Following collection place Vacutainer® tube on ice, then centrifuge, aliquot plasma into a plastic vial, and freeze. If possible, discontinue insulin medication prior to collection.

Red Top Tube
Normal Volume
3 mL plasma
Minimum Volume
1 mL plasma

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.