Gastric juice for the diagnosis of H pylori infection in patients on proton pump inhibitors

Table 1 Comparison of histology, gastric biopsy and juice PCR for the diagnosis of H pylori infection with and without PPI n (%)

	Medication		P value
	On PPI	Without PPI
	n = 37	n = 48
Histology
H pylori positive gastritis	23 (62)	34 (71)	0.24
H pylori negative gastritis	14 (38)	14 (29)
Gastric juice PCR
Positive	30 (81)	36 (75)	0.50
Negative	7 (19)	12 (25)
Gastric biopsy PCR
Positive	35 (95)	37 (77)	0.02
Negative	2 (5)	11 (23)

Table 2 Comparison of gastric juice PCR and histology using gastric biopsy PCR as the gold standard n (%)

	PCR of gastric biopsy		P value
Over all (n = 85)
Histology	Positive	Negative
Positive	56 (78)	1 (8)	< 0.001
Negative	16 (22)	12 (92)
Gastric juice PCR
Positive	63 (87)	3 (23)	< 0.001
Negative	9 (13)	10 (77)
On PPI (n = 37)
Histology
Positive	23 (66)	0	0.17
Negative	12 (34)	2 (100)
Gastric juice PCR
Positive	30 (86)	0	0.003
Negative	5 (14)	2 (100)
No PPI (n = 48)
Histology
Positive	33 (89)	1 (9)	< 0.001
Negative	4 (11)	10 (91)
Gastric juice PCR
Positive	33 (89)	3 (27)	< 0.001
Negative	4 (11)	8 (73)

Table 3 Comparison of gastric juice PCR and histology with and without PPI using gastric biopsy PCR as the gold standard

	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	Likelihood ratio LR+	Likelihood ratio LR-	Accuracy (%)
Over all (n = 85)
Histology	77	92	98	43	9.6	0.25	80
Gastric juice PCR	87	77	95	53	3.7	0.16	85
On PPI (n = 37)
Histology	73	100	100	14	0.6	2.7	74
Gastric juice PCR	86	100	100	29	9.5	1.4	86
No PPI (n = 48)
Histology	89	90	97	71	0.89	0.12	85
Gastric juice PCR	89	72	91	67	3.17	0.15	85