Table 1

The proportion of fresh samples from different sources with pH ≤5.5 and the diagnostic accuracy of using this cut-off to detect gastric source overall, and in the presence or absence of prior antacid medication and confounding factors

SampleAllAntacid medicationNo antacid
medication
All confounding
factors*
Number with pH ≤5.5/total n (%)
Gastric65/96 (68)30/42 (71)35/54 (65)32/44 (73)
Oesophageal59/90 (66)26/41 (63)33/49 (67)26/42 (62)
Saliva2/101 (2)2/40 (5)0/61 (0)2/43 (5)
Bronchial0/103 (0)0/41 (0)0/62 (0)0/45 (0)