Intra-individual variability of CO₂ breath isotope enrichment compared to blood glucose in the oral glucose tolerance test.

Background: Glucose tolerance can be assessed noninvasively using (13)C-labeled glucose added to a standard oral glucose load, by measuring isotope-enriched CO(2) in exhaled air. In addition to the clear advantage of the noninvasive measurements, this approach may be of value in overcoming the high variability in blood glucose determination.

Methods: We compared within-individual variability of breath CO(2) isotope enrichment with that for blood glucose in a 75-g oral glucose tolerance test (OGTT) by adding 150 mg of d-[(13)C]glucose ((13)C 99%) to a standard 75-g glucose load.

Novel noninvasive breath test method for screening individuals at risk for diabetes.

Objective: Diagnosis of pre-diabetes and early-stage diabetes occurs primarily by means of an oral glucose tolerance test (OGTT), which requires invasive blood sampling. The aim of this study was to determine whether differences exist in breath (13)CO(2) excretion during a (13)C-labeled OGTT between individuals with normal glucose tolerance (NGT) and individuals with pre-diabetes and early-stage diabetes (PDED) and whether these differences correlated with blood glucose kinetics.

Research Design And Methods: Blood and breath samples were collected at baseline and every 30 min for a 10-h period after ingestion of 75 g glucose isotopically labeled with 150 mg [U-(13)C(6)]D-glucose.

Effect of triglyceride structure on fecal excretion of 13C-labeled triglycerides.

Objective: The aim of this work was to determine the effects of specific changes in the structure of (13)C-labeled triglyceride (TG*) on its fecal excretion relative to total stool fat excretion determined simultaneously in patients with reduced exocrine pancreatic function.

Methods: A series of 47 studies were conducted in 26 young cystic fibrosis (CF) patients and 11 adult patients with chronic pancreatitis over a five year period. Each test consisted of ingesting a single high fat test meal containing both (13)C-labeled triglyceride (TG*) and dysprosium chloride (DyCl(3)) a nonabsorbable marker of intestinal transit; in most studies the food colorant brilliant blue (FD&C blue #1) was administered along with the DyCl(3).

Dysprosium chloride as a nonabsorbable gastrointestinal marker for studies of stable isotope-labeled triglyceride excretion in man.

Objective: The aim of this work was to determine if dysprosium chloride (DyCl(3)) is a suitable nonabsorbable marker for studies of labeled-triglyceride excretion in cystic fibrosis patients allowing excretion to be determined accurately after analysis of one or two stools.

Methods: A series of 66 absorption studies were conducted in 36 young cystic fibrosis patients over a five year period. All tests consisted of ingesting a single test meal containing both (13)C-labeled triglyceride (TG*) and DyCl(3); in most studies the food colorant brilliant blue (FD&C blue #1) was administered along with the DyCl(3).