Validation of a stable isotope gastric emptying test for normal, accelerated or delayed gastric emptying

Abstract

To validate a 13C-Spirulina platensis breath test for measurement of accelerated or delayed gastric emptying, we measured gastric emptying of egg containing 13C-S. platensis and 99mTc-sulphur colloid by breath 13 CO2 every 15 min over 3 h and scintigraphy every 15-30 min over 5 h in 57 healthy volunteers. Thirty-three received no treatment, 10 received erythromycin, and 14 atropine. A generalized linear regression model predicted half-emptying time by scintigraphy (t1/2S) from breath 13CO2 (t1/2B) data. Accuracy was assessed by standard deviation (SD) of differences between t1/2S and t1/2B and by receiver operating characteristic (ROC) curves. Regression models using breath samples at baseline, and 45, 90, 105 and 120 min, predicted t1/2B (mean +/- SD) at 118 +/- 59 min, similar to t1/2S (118 +/- 67 min). Correlation between t1/2B and t1/2S was significant (r=0.88; P < 0.0001). Differences between t1/2S and t1/2B were: 18-19.2 min for t1/2 < 70-150 min, and 68.3 min for t1/2 > 150 min. Breath test detected abnormal emptying with a sensitivity of 86% and specificity of 80%. Thus, the 13C-S. platensis test measures gastric emptying t1/2 for solids, which is accelerated or delayed to mimic a range of conditions from dumping syndrome to severe gastroparesis, with high sensitivity and specificity. Additional breath samples are needed to increase sensitivity in detecting accelerated gastric emptying.

Methods for measurement of gastric motility

“…In studies comparing 13 C gastric emptying breath tests (GEBT) performed simultaneously with scintigraphy, the 13 C GEBT provides an accurate assessment of the gastric emptying of solids with an acceptable coefficient of variation that is comparable to scintigraphy (25) and is similar with two different meal substrates [egg and biscuit (77)]. 13 C-S. platensis GEBT was able to identify accelerated or delayed gastric emptying induced pharmacologically with erythromycin or atropine (134). At present, there is no standardized meal for the breath test.…”

“…Breath excretion of 13 CO 2 from either the 13 C-S. Platensis or the [ 13 C]octanoic acid GEBTs may be affected by hemodynamic changes, including vigorous physical exercise, sepsis, or hyperdynamic circulation. The optimal mathematical analysis for GEBT is the subject of controversy with different approaches and corrections recommended (51,77,82,94,120,134). This also needs standardization before application of GEBT in clinical practice.…”

Prevalence of Delayed Gastric Emptying in Diabetic Patients and Relationship to Dyspeptic Symptoms

“…CO 2 production was corrected for age, sex, height, and weight using the algorithms of Schofield (22). Mathematical analysis of the 13 C values in the breath samples was performed using a generalized linear regression model adopted from Lee et al (18) and Viramontes et al (19).…”

“…The advantages of this test over the gold standard, the radioisotope technique, are the relatively low costs and the lack of radiation involved. Therefore, the 13 C-octanoic breath test has become a valuable and reliable tool to investigate gastric emptying in large cohorts of patients (19).…”

Evaluation of gastrointestinal transit in clinical practice: position paper of the American and European Neurogastroenterology and Motility Societies

“…37,41 Strengths and confounding issues No radiation is involved and the test is simple and does not require any special equipment on-site, and can be performed in the office or bed side. There are pitfalls in the interpretation of this test.…”