GEBT & Gastroparesis

GEBT & GASTROPARESIS

GEBT & GASTROPARESIS

For many patients and physicians, the pathway to a definitive diagnosis can be complex, slow and frustrating. At Cairn Diagnostics, our mission is to develop tests that eliminate complexity and create a safer, faster and clearer path to diagnosis.

Use of our proprietary and validated analytical methods allows us to create diagnostic tests that are user- and patient-friendly and convenient, yet powerful in their ability to deliver a definitive diagnosis.

CAIRN GEBT FOR GASTROPARESIS

Gastroparesis is characterized by delayed gastric emptying in the absence of a mechanical obstruction in the stomach.

While scintigraphy can be used to diagnose gastroparesis, it requires referral to specialized outpatient centers and exposes patients to radiation. As a result, scintigraphy is often used late in the diagnostic pathway, if at all, after other conditions such as dyspepsia, gastroesophageal reflux disease and ulcers are first ruled out.

This challenging pathway can extend the time required to arrive at a definitive diagnosis. Patients are often treated empirically and without confirmation of delayed stomach emptying. Moreover, because symptomology is not highly predictive of gastroparesis, empirical treatment may be unsuccessful, resulting in the patient using disproportionately more health care services and incurring greater health care costs.

The Cairn 13C-Spirulina Gastric Emptying Breath Test (GEBT) is a non-radioactive, non-invasive and conveniently administered test for measurement of the rate of gastric emptying in adults. Validated against the gold standard reference method of gastric scintigraphy, the Cairn GEBT enables rapid and accurate identification of gastroparesis.

The test can be administered right in the physician’s office and does not require imaging equipment, specialized training or radioactive material. Patient test results are sent directly to the ordering physician allowing for timely diagnosis of gastroparesis without the need for expensive, time-consuming referrals.

THE SCIENCE BEHIND THE CAIRN GASTRIC EMPTYING BREATH TEST

After an overnight fast and providing duplicate pre-meal breath samples, the patient consumes the 13C-Spirulina Gastric Emptying Breath Test (GEBT) meal. This meal consists of 27 grams of re-hydrated, precisely formulated, pasteurized scrambled egg mix containing a dose of 43 mg of 13C (provided by approximately 100 mg of 13C-Spirulina), 6 saltine crackers and 6 ounces (180 mL) of potable water. The caloric value of the meal is approximately 230 kCal.

As the egg meal containing the 13C-Spirulina is triturated by the stomach to a particle size of 1 – 2 mm, it passes through the pylorus into the intestine. In the upper small intestine, the labeled products of 13C-Spirulina digestion (proteins, carbohydrates and fats) are absorbed and subsequently metabolized, giving rise to 13C-labeled carbon dioxide (13CO2) expired in the breath. Breath samples, collected periodically in capped glass tubes before and after test meal administration, are returned to a central laboratory for analysis by gas isotope ratio mass spectrometry (GIRMS) to determine the ratio of 13CO2 to 12CO2 in each sample.

By measuring the change in this ratio over time as compared to the pre-meal value, the rate of 13CO2 excretion can be calculated and the individual’s gastric emptying rate determined. The rate of gastric emptying is proportional to the rate of 13CO2 excretion at any measurement time “t.”

Cairn GEBT test results are reported using the metric “kPCD.” At any measurement time t, kPCD(t) = 1000 X [Percent carbon-13 dose (PCD) in test meal excreted (as 13CO2) per minute]. A larger kPCD value means a faster 13CO2 excretion rate which is proportional to a faster rate of gastric emptying.

Once the clinical laboratory has assayed each of the patient’s breath samples, test results are presented as 13CO2 excretion curves, depicting excretion rate (kPCD per minute) over time. Increasing rates of 13CO2 excretion (kPCD min-1) reflect increasing rates of gastric emptying.  The shape and height of the patient’s excretion curve relative to the reference range provides diagnostically valuable information for identifying gastroparesis.