An optimized 13C-urea breath test for the diagnosis of H pylori infection

Table 1 Performance of protocols (P1 and P2) in terms of sensitivity, specificity, accuracy, positive and negative predictive values, Youden index and likelihood ratios for a positive (LR+ve) or (LR-ve) test with the different DOB cut-off values at 10, 20 and 30 min

Time(min)	DOB	Sensitivity		Specificity		Accuracy		Positive predictive value		Negative predictive value		Youden index		LR+ve		LR-ve
		P1	P2	P1	P2	P1	P2	P1	P2	P1	P2	P1	P2	P1	P2	P1	P2
10	0.5	100	97.83	45.83	62.5	81.43	85.71	77.97	83.33	100	93.75	0.46	0.6	1.85	2.61	1	0.03
	1.0	100	97.83	83.33	79.17	94.29	91.43	92	90.0	100	95	0.83	0.77	6.00	4.7	1	0.03
	1.5	100	97.83	95.83	95.83	98.57	97.14	97.87	97.83	100	95.83	0.96	0.94	24.00	23.48	1	0.02
	2.0	100	97.83	100	100	100	98.57	100	100	100	96	1.00	0.98	2	2	1	0.02
	2.5	100	95.65	100	100	100	97.14	100	100	100	92.31	1.00	0.96	2	2	1	0.04
	3.0	97.83	95.65	100	100	98.57	97.14	100	100	96.0	92.31	0.98	0.96	2	2	0.02	0.04
	3.5	97.83	95.65	100	100	98.57	97.14	100	100	96.0	92.31	0.98	0.96	2	2	0.02	0.04
	4.0	95.65	95.65	100	100	97.14	97.14	100	100	92.31	92.31	0.96	0.96	2	2	0.04	0.04
	4.5	93.48	95.65	100	100	95.71	97.14	100	100	88.89	92.31	0.93	0.96	2	2	0.07	0.04
	5.0	86.96	95.65	100	100	91.43	97.14	100	100	80	92.31	0.87	0.96	2	2	0.13	0.04
	5.5	84.78	95.65	100	100	90	97.14	100	100	77.42	92.31	0.85	0.96	2	2	0.15	0.04
20	0.5	100	97.83	66.67	62.5	88.57	85.71	85.19	83.33	100	93.75	0.67	0.6	3.00	2.61	1	0.03
	1.0	100	97.83	95.83	75	98.57	90	97.87	88.24	100	94.74	0.96	0.73	24.00	3.91	1	0.03
	1.5	100	97.83	100	83.33	100	92.86	100	91.84	100	95.24	1.00	0.81	2	5.87	1	0.03
	2.0	100	97.83	100	100	100	98.57	100	100	100	96	1.00	0.98	2	2	1	0.02
	2.5	100	95.65	100	100	100	97.14	100	100	100	92.31	1.00	0.96	2	2	1	0.04
	3.0	97.83	95.65	100	100	98.57	97.14	100	100	96	92.31	0.98	0.96	2	2	0.02	0.04
	3.5	95.65	95.65	100	100	97.14	97.14	100	100	92.31	92.31	0.96	0.96	2	2	0.04	0.04
	4.0	89.13	95.65	100	100	92.86	97.14	100	100	82.76	92.31	0.89	0.96	2	2	0.11	0.04
	4.5	84.78	95.65	100	100	90	97.14	100	100	77.42	92.31	0.85	0.96	2	2	0.15	0.04
	5.0	82.61	95.65	100	100	88.57	97.14	100	100	75	92.31	0.83	0.96	2	2	0.17	0.04
	5.5	82.61	93.48	100	100	88.57	95.71	100	100	75	88.89	0.83	0.93	2	2	0.17	0.07
30	0.5	100	97.83	54.17	45.83	84.29	80	80.7	77.59	100	91.67	0.54	0.44	2.18	1.81	1	0.05
	1.0	100	97.83	91.67	70.83	97.14	88.57	95.83	86.54	100	94.44	0.92	0.69	12.00	3.35	1	0.03
	1.5	100	97.83	100	83.33	100	92.86	100	91.84	100	95.24	1.00	0.81	2	5.87	1	0.03
	2.0	95.65	97.83	100	91.67	97.14	95.71	100	95.74	92.31	95.65	0.96	0.89	2	11.74	0.04	0.02
	2.5	91.3	97.83	100	100	94.29	98.57	100	100	85.71	96	0.91	0.98	2	2	0.09	0.02
	3.0	84.78	95.65	100	100	90	97.14	100	100	77.42	92.31	0.85	0.96	2	2	0.15	0.04
	3.5	82.61	95.65	100	100	88.57	97.14	100	100	75	92.31	0.83	0.96	2	2	0.17	0.04
	4.0	78.26	95.65	100	100	85.71	97.14	100	100	70.59	92.31	0.78	0.96	2	2	0.22	0.04
	4.5	78.26	95.65	100	100	85.71	97.14	100	100	70.59	92.31	0.78	0.96	2	2	0.22	0.04
	5.0	76.09	95.65	100	100	84.29	97.14	100	100	68.57	92.31	0.76	0.96	2	2	0.24	0.04
	5.5	71.74	93.48	100	100	81.43	95.71	100	100	64.86	88.89	0.72	0.93	2	2	0.28	0.07

DOB: Delta-over-baseline;

¹: ≈ 0;

²: Φ +.

Table 2 Distribution of DOB values in H pylori positive and negative individuals for both protocols at 10, 20 and 30 min

H pylori-positive individuals
	10 min		20 min		30 min
	Protocol 1	Protocol 2	Protocol 1	Protocol 2	Protocol 1	Protocol 2
Mean	17.38	17.69	18.25	22.32	15.44	22.08
Median	13.64	12.02	12.63	17.07	10.98	17.50
SD	14.47	12.68	22.80	15.01	17.75	13.00
H pylori-negative individuals
	10 min		20 min		30 min
	Protocol 1	Protocol 2	Protocol 1	Protocol 2	Protocol 1	Protocol 2
Mean	0.32	0.33	0.11	0.45	0.21	0.62
Median	0.51	0.32	0.28	0.34	0.38	0.59
SD	0.91	0.8	0.77	0.86	0.84	0.91

DOB: Delta-over-baseline.

Table 3 ¹³C-UBT protocol with best diagnostic performance from each study with samples obtained within 30 min of ¹³C-urea administration: Review of literature

First author(reference)	Year	Measuring equipment	Gold standard	n	Pre-analytical	13C-urea dose(mg)	13C-urea formulation and via of administration	Test meal	Additional information related to 13C-urea administration	t	Cut-off point(DOB)	Sens.(%)	Spec.(%)	PPV(%)	NPV(%)	Acc.(%)
Braden[32]	1994	IRMS	13C-UBT	217	Overnight fasting	75	NA	None		20	5	99	100
Koletzko[33]	1995	IRMS,NDIRS	13C-UBT	51	Overnight fasting	75	Powder in 150 mL 0.033 mol/L citric acid solution	Taken with 13C-urea		15	5	100	100
Klein[34]	1996	IRMS	H	465	NA	125	Powder in 90 mL sterile water (Meretek kit)	Ensure		30	2.4	95.4	87.9			94.8
Malaty[35]	1996	IRMS	H, RUT, C	66	Overnight fasting	125	Powder in 100 mL water	None		20	2.4	96	100
Taniguchi[36]	1996	NDIRS	H	153	Overnight fasting	100	Powder in 30 mL water	None		15	1	97.8	74
Domínguez-Muños[37]	1997	IRMS	H, RUT, C	80	Overnight fasting	80	Powder in 50 mL water	200 mL 0.1 mol/L citric acid solution		30	4	100	100
Epple[38]	1997	IRMS	H	77	Overnight fasting	75	NA	Citric acid		30	1.3	96	100
Kato[39]	1998	IRMS	H, C, RUT	133	Overnight fasting	100	Powder in 100 mL of water	None	Mouth rinsing after 13C-urea	10	3.5	99	100
Miwa[40]	1998	IRMS	H	409	8 h fasting	100	Powder	None	Mouth rinsing before and after 13C-urea	20	5	97	97
Ohara[41]	1998	IRMS	H, RUT, C	248	Overnight fasting	100	Powder in 100 mL tap water	None	Mouth rinsing after 13C-urea	20	2.5	98	98			98
Hamlet[42]	1999	IRMS	13C-UBT, H, RUT, C	134	Overnight fasting	100	Two tablets (Diabact UBT) with 50 mg of 13C-urea + 456 mg of anhydrous citric acid swallowed with 200 mL of water	Taken with 13C-urea		10	1.8	95	100
Leodolter[43]	1999	IRMS	H, RUT, C	50	NA	75	Powder in 200 mL 0.1 mol/L citric acid solution	Taken with 13C-urea		30	4	100	100
Leodolter[44]	1999	IRMS	H, RUT, C	233	NA	75	Powder in 200 mL citric acid solution	Taken with 13C-urea		30	4	95	98			97
Savarino[45]	1999	IRMS	H, RUT	134	Overnight fasting	75	Powder in 150 mL 0.033 mol/L citric acid solution	Taken with 13C-urea		30	5	100	100
Van der Hulst[46]	1999	LARA	H, C	544	NA	100	Powder in 50 mL sterile water	Ensure		30	6.3-7.5	93-95	94-96	95-98	86-94
Gisbert[47]	2000	IRMS	13C-UBT,H	53	Overnight fasting	100	Powder in 50 mL water (TAU-KIT)	None		30	3.3-3.9	100	100
Peng[48]	2000	IRMS	H, RUT, C	136	6 h fasting	100	Powder in 50 mL sterile water	100 mL milk	Mouth rinsing after 13C-urea and laid on their sides, changing sides every 5 min	15	4.8	94	89
Riepl[49]	2000	NDIRS	H, C	100	Overnight fasting	75	Powder in 200 mL orange juice	Taken with 13C-urea		15	6.5	92	94	89	94
Savarino[50]	2000	IRMS	H, RUT	117	Overnight fasting	75	Powder in 150 mL 0.033 mol/L citric acid solution	Taken with 13C-urea		30	5	98	97	98	97	98
Sheu[51]	2000	IRMS	H, C	441	Overnight fasting	100	NA	100 mL of fatty test meal	Mouth rinsing before and after 13C-urea	15	4	98	97
Sheu[52]	2000	IRMS,NDIRS	H, C	177	Overnight fasting	50	NA	100 mL citric acid solution	Mouth rinsing after 13C-urea	15	3.5	96	99	99	97
Wong[53]	2000	IRMS	H, RUT	202	Overnight fasting	75	Powder in 50 mL distilled water	2.4 g of citric acid		30	5	96	98	98	96	97
Yoshida[54]	2000	LARA	H, C, PCR	104	Overnight fasting	100	Powder in 50 mL distilled water	None	Mouth rinsing after 13C-urea	20	2.7	98	100			99
Mana[55]	2001	NDIRS	H	223	Overnight fasting	75	Powder	20 mL 0.1 mol/L citric acid solution		10		100	95	94	100
Wong[56]	2001	IRMS	H, RUT	101	Overnight fasting	75	Powder in 50 mL water	None		30	3.5-4.5	100	100			100
Chua[57]	2002	IRMS	H, RUT, S	100	NA	100	Powder in solution Containing citric acid and 13C-urea		Pacients laid on their left side for 30 min	30	3.5	94	100	100	89
Liao[58]	2002	IRMS	H, RUT	152	Overnight fasting	50	Powder in 50 mL sterile water	200 mL full-cream cow's milk	Patients gargled with water 3 times after 13C-urea and laid on their sides, changing sides every 3 min	15	2.5-3.0	99	97	99	97	99
Ng[59]	2002	IRMS	H, RUT	123	Regular meal within 2 h of the 13C-urea	75	Powder in 50 mL water	2.4 g citric acid in 200 mL solution		30	5.5	93	97	100	97
Chen[60]	2003	NDIRS	H, RUT, C, SAT	586	Overnight fasting	100	Powder in 100 mL of water	None	Patients gargled with water 3 times after 13C-urea and laid down on the left side for 5 min	20	3.5	98	97			98
Gatta[61]	2003	IRMS	H, RUT, C	200	Overnight fasting	50	Tablet (Diabact UBT) with 50 mg of 13C-urea and 456 mg of anhydrous citric acid swallowed with 200 mL of water	Citric acid		10	1.65-3.15	100	100
Gisbert[62]	2003	IRMS	H, RUT	36	Overnight fasting	100	Powder in 50 mL water(TAU-KIT)	200 mL solution with 4.2 g citric acid		30	5	96	100	100	91
Wong[63]	2003	IRMS	H, RUT	150	Overnight fasting	50	Tablet (Diabact UBT) with 50mg of 13C-urea and 456 mg of anhydrous citric acid swallowed with 200 mL of water	Citric acid		20	2.1	100	100
Ohara[64]	2004	IRMS	13C-UBT, H, C, RUT	254	Overnight fasting	100	Film-coated tablet swallowed with 100 mL of water	None		20	2.5	98	98			98
Urita[65]	2004	IRMS	H, S	129	Overnight fasting	100	Powder in 100 mL tap water	None	Sample taken through nostril	20	2.5	100	100			100
Beiki[66]	2005	NDIRS	14C-UBT, H, RUT	76	Overnight fasting	75	Powder in 200 mL orange juice			30	3.5	100	97	98	100	99
Kopacova[67]	2005	IRMS	13C-UBT	27	Overnight fasting	100	Powder in 50 mL distilled water with 1 g citric acid	150 mL Distilled water with 3 g citric acid, orange juice or distilled water		10	3.5	100	100			100
Peng[68]	2005	IRMS	H, RUT, C	50	6 h fasting	100	Capsule with water	None	Mouth rinsing before and after 13C-urea and laid on their sides, changing sides every 5 min	15	4-5	100	100			100
Gatta[69]	2006	IRMS	H, RUT	100	Overnight fasting	25	Dissolved in water	Citric acid (1 g)		30	4.4-6.26	100	100
Mauro[70]	2006	IRMS	H, C	176	Overnight fasting	75	Powder in 100 mL citric acid solution	Taken with 13C-urea		30	3	100	99	95-98	100
Mauro[71]	2006	IRMS	H, C	67	Overnight fasting	75	Powder in 100 mL citric acid solution	Taken with 13C-urea		10	3	100	96	95-98	99-100
Present study	2007	IRMS	13C-UBT	70	Overnight fasting	50	Powder in 10 mL sterile water immediately followed by 200 mL sterile water	None	Patients made a circular motion around the waistline for a few times	10	2.0-2.5	100	100	100	100	100

n: Participating individuals; t: Sampling time; PPV: Positive predictive value; NPV: Negative predictive value; Acc: Accuracy; UBT: Urea breath test; H: histology; C: Culture; RUT: Rapid urease test; S: Serology; NA: Not available; IRMS: Isotope ratio mass spectrometry; NDIRS: Non-dispersive infrared spectrometry; LARA: Laser assisted ratio analyser; DOB: Delta-over-baseline.