TABLE 4.

Established test protocol for ¹³C‐UBT in adults and children

Reference		Test solution	Breath sampling	Cut off	Validity	Remarks
Leodolter 1999 15	Adults	75 mg 13 C‐urea dissolved in 200 ml 0.1 mol/L citric acid solution (∼4 g/200 ml water) with two tablets artificial sweetener	Before and 30 min after ingestion	≥4‰	SENS 95% SPEC 98% ACC 97%	Equal performance as test with citric acid solution 10 min before marker ingestion;
						With 200 ml orange juice instead of citric acid lower SENS (88%) with equally high SPEC (100%) 54 ; with semiliquid meals longer test duration required 55
Elitsur et al. 2009 56	Children	75 mg 13 C‐urea and 2 g citric acid dissolved in 4 ounces (∼120 ml) potable water	Baseline and 15 min after ingestion	≥2.4‰	SENS 97.9%	Test performed best in children aged >6 years; in ages 2–5 calculation of urea hydrolysis rate can lead to higher SENS and SPEC compared with DOB values
					SPEC 96.1%
					PPV 90.4%
					NPV 99.2%

Abbreviations: ACC, accuracy; DOB, δ over baseline; NPV, negative predictive value; PPV, positive predictive value; SENS, sensitivity; SPEC, specificity; UBT, urea breath test.