Patients with Gastric Antral Vascular Ectasia with cirrhosis or chronic kidney disease will undergo a gastric emptying breath test. This test is designed to show how quickly the stomach empties solids by measuring labeled carbon dioxide in a patient's breath.

Patients without Gastric Antral Vascular Ectasia with cirrhosis or chronic kidney disease will undergo a gastric emptying breath test. This test is designed to show how quickly the stomach empties solids by measuring labeled carbon dioxide in a patient's breath.

13C-Spirulina GEBT (Cairn Diagnostics) is non-radioactive, non-invasive breath based test validated against scintigraphy for the measurement of gastric emptying. Patients will be mailed test kits to be done in their homes remotely along with telehealth assistance from the study team. After overnight fast and providing duplicate pre-meal breath samples, the patient consumes 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.Patient will provide breath samples into provided glass tubes before and after test meal administration which are then mailed back to a central laboratory for analysis by gas isotope ratio mass spectrometry.

The Nepean Dyspepsia Index is a 10-item questionnaire that measures dyspepsia problems. Each item is scored from 1-5. 1 = Not at all, 5 = Extremely. Total scores range from 10 - 50, lower scores indicate less dyspepsia problems, higher scores indicate more dyspepsia problems.

The Abridged Bowel Disease Questionnaire is a 14-item questionnaire that measures Bowel Disease symptoms. Each item is scored as yes or no. Scores answering yes indicate more bowel disease, and scores answering no indicate less or no bowel disease.

The Leuven Postprandial Distress Scale is an 8-item questionnaire that measures symptoms of dyspepsia. Each item is scored from 1-5. 1 = Absent, 5 = very severe. Total scores range from 0-40 Lower scores indicate less or no symptoms of dyspepsia, higher scores indicate more symptoms of dyspepsia.

the Bowel Disease Screen Questionnaire is a 20 item questionnaire that measures stomach and bowel disease symptoms. Each item is scored from 1-5. 1=not at all, 5=Extremely. Total scores range from 10-95.

The C-Spirulina Gastric Emptying Breath Test is a non-radioactive, Non-invasive test for measurement of the rate in gastric emptying in adults by measuring the C-13 levels in the breath.