{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T02:36:29Z","timestamp":1774665389405,"version":"3.50.1"},"reference-count":24,"publisher":"BMJ","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gut"],"published-print":{"date-parts":[[1994,3]]},"abstract":"<jats:p>For oesophageal pH monitoring, the pH probe is usually positioned 5 cm above the lower oesophageal sphincter (LOS). This is by convention, and has not been compared with other positions in its ability to discriminate between physiological and abnormal acid reflux. Using simultaneous two level 24 hour pH monitoring (5 and 10 cm above manometrically determined LOS) in 31 controls and 51 patients with reflux oesophagitis, the significance of the precise position of the probe in the oesophagus was examined. Secondly, this study compared the discrimination between the two groups achieved at the two levels. Patients had greater acid exposure than controls at both levels. In controls, acid exposure was greater at distal than at the proximal level except the supine acid exposure, which was similar at both levels. In patients, acid exposure was greater at the distal level for all variables (median % of total time pH &lt; 4 = 11.7 v 7.6; p = 0.001). There was excellent correlation between the two levels for all variables in controls (r = 0.883, 0.935, 0.813, and p &lt; 0.001 for percentage of time pH &lt; 4 for total, supine, and upright times) as well as in patients (r = 0.848, 0.848, 0.779, and p &lt; 0.001). On discriminant and receiver operating characteristic analysis, pH threshold 4 seemed as good as or better than other pH thresholds in discriminating between controls and patients. The percentage of total time pH below 4 seemed to discriminate as well or better than other variables at both levels. The distal level (5 cm above LOS) provided slightly better discrimination than proximal level (10 cm) (percentage of subjects correctly classified=81.7 v 75.6). The critical factor for the reliability of the test is not the precise position of the pH probe relative to the LOS, but that the same position is consistently used in patients and controls.<\/jats:p>","DOI":"10.1136\/gut.35.3.304","type":"journal-article","created":{"date-parts":[[2007,9,18]],"date-time":"2007-09-18T17:41:31Z","timestamp":1190137291000},"page":"304-308","source":"Crossref","is-referenced-by-count":19,"title":["Simultaneous two level oesophageal pH monitoring in healthy controls and patients with oesophagitis: comparison between two positions."],"prefix":"10.1136","volume":"35","author":[{"given":"P","family":"Singh","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R H","family":"Taylor","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D G","family":"Colin-Jones","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[1994,3,1]]},"reference":[{"key":"ref_1","first-page":"225","article-title":"Detection of gastroesophageal reflux by simultaneous measurement of intraluminal","volume-title":"pressure and pH. Proc Soc Exp Biol Med 1958","volume":"98","author":"Tuttle, S.G.; Grossman, M.I.","unstructured":"Tuttle SG, Grossman MI. Detection of gastroesophageal reflux by simultaneous measurement of intraluminal pressure and pH. Proc Soc Exp Biol Med 1958; 98: 225-7."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"656","DOI":"10.1016\/S0022-5223(19)37879-1","article-title":"and clinical use of 24-hour esophageal pH monitoring","volume":"79","author":"DeMeester, T.R.; Wang, C.I.; Wermly, J.A.; Pellegrini, C.A.; Little, A.G.; Klementschitsch, P.","year":"1980","unstructured":"DeMeester TR, Wang CI, Wermly JA, Pellegrini CA, Little AG, Klementschitsch P, et al. Technique, indications, and clinical use of 24-hour esophageal pH monitoring. ] Thorac Cardiovasc Surg 1980; 79: 656-70.","journal-title":"Thorac Cardiovasc Surg"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1136\/gut.28.5.519","article-title":"Daytime gastro-oesophageal reflux is important in oesophagitis","volume":"28","author":"de Caestecker JS; JN, Blackwell; A, Pryde; RD, Heading","year":"1987","unstructured":"de Caestecker JS, Blackwell JN, Pryde A, Heading RD. Daytime gastro-oesophageal reflux is important in oesophagitis. Gut 1987; 28: 519-26.","journal-title":"Gut"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/0016-5085(87)90318-0","article-title":"Optimal thresholds, sensitivity, and specificity of long-term pH-metry for the detection ofgastrooesophageal reflux disease","volume":"93","author":"Schindlbeck, N.E.; Heinrich, C.; Konig, A.; Dendorfer, A.; Pace, F.; Muller-Lissner, S.A.","year":"1987","unstructured":"Schindlbeck NE, Heinrich C, Konig A, Dendorfer A, Pace F, Muller-Lissner SA. Optimal thresholds, sensitivity, and specificity of long-term pH-metry for the detection ofgastrooesophageal reflux disease. Gastroenterology 1987; 93: 85-90.","journal-title":"Gastroenterology"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/S0140-6736(87)91921-0","article-title":"Is 24 h ambulatory oesophageal pH monitoring useful in a district general hospital?","volume":"i:","author":"Donald, I.P.; Ford, G.A.; Wilkinson, S.P.","year":"1987","unstructured":"Donald IP, Ford GA, Wilkinson SP. Is 24 h ambulatory oesophageal pH monitoring useful in a district general hospital? Lancet 1987; i: 89-92.","journal-title":"Lancet"},{"key":"ref_6","first-page":"1242","article-title":"Does the position of the probe affect the results of oesophageal pH monitoring?","volume":"27","author":"Walker, S.J.; Holt, S.; Sanderson, C.J.; Stoddard, C.J.; Shields, R.","year":"1986","unstructured":"Walker SJ, Holt S, Sanderson CJ, Stoddard CJ, Shields R. Does the position of the probe affect the results of oesophageal pH monitoring? Gut 1986; 27: A1242.","journal-title":"Gut"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1016\/S0140-6736(87)90261-3","article-title":"24 hour monitoring of oesophageal pH in outpatients","volume":"i:","author":"Dehn, T.C.; Kettlewell, M.","year":"1987","unstructured":"Dehn TC, Kettlewell M. 24 hour monitoring of oesophageal pH in outpatients [Letter]. Lancet 1987; i: 625-6.","journal-title":"Lancet"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"399","DOI":"10.3109\/00365528609015154","article-title":"Oesophageal reflux tests, manometry, endoscopy, biopsy, and radiology in healthy subjects","volume":"21","author":"Johansson, K.E.; Boeryd, B.; Fransson, S.G.; Tibbling, L.","year":"1986","unstructured":"Johansson KE, Boeryd B, Fransson SG, Tibbling L. Oesophageal reflux tests, manometry, endoscopy, biopsy, and radiology in healthy subjects. Scand J Gastroenterol 1986; 21: 399-406.","journal-title":"Scand J Gastroenterol"},{"key":"ref_9","first-page":"579","article-title":"Evaluation of the 24 hour pH test at two different levels of the esophagus","volume-title":"disorders: pathophysiology and therapy","author":"Johansson, K.E.; Tibbling, L.","year":"1985","unstructured":"Johansson KE, Tibbling L. Evaluation of the 24 hour pH test at two different levels of the esophagus. In: DeMeester TR, Skinner DB, eds. Esophageal disorders: pathophysiology and therapy. New York: Raven Press, 1985: 579-80."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1016\/0016-5085(91)90011-9","article-title":"Regional esophageal distribution and clearance of refluxed gastric acid","volume":"101","author":"Shaker, R.; Dodds, W.J.; Helm, J.F.; Kern, M.K.; Hogan, W.J.","year":"1991","unstructured":"Shaker R, Dodds WJ, Helm JF, Kern MK, Hogan WJ. Regional esophageal distribution and clearance of refluxed gastric acid. Gastroenterology 1991; 101: 355-9.","journal-title":"Gastroenterology"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1305","DOI":"10.1136\/gut.30.10.1305","article-title":"Histamine-2-receptor antagonists in gastrooesophageal reflux","volume":"30","author":"Colin-Jones, D.G.","year":"1989","unstructured":"Colin-Jones DG. Histamine-2-receptor antagonists in gastrooesophageal reflux. Gut 1989; 30: 1305-8.","journal-title":"Gut"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1590","DOI":"10.1136\/gut.33.12.1590","article-title":"Oesophageal motor function before and after healing of oesophagitis","volume":"33","author":"Singh, P.; Adamapoulos, A.; Taylor, R.H.; Colin-Jones, D.G.","year":"1992","unstructured":"Singh P, Adamapoulos A, Taylor RH, Colin-Jones DG. Oesophageal motor function before and after healing of oesophagitis. Gut 1992; 33: 1590-6.","journal-title":"Gut"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1148\/radiology.143.1.7063747","article-title":"The meaning and use of the area under a receiver operating characteristic (ROC) curve","volume":"143","author":"Hanley, J.A.; McNeil, B.J.","year":"1982","unstructured":"Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology 1982; 143: 29-36.","journal-title":"Radiology"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"720","DOI":"10.1007\/BF00956712","article-title":"Perceptual and statistical analysis of cardiac phase and amplitude images","volume":"18","author":"Houston, A.; Craig, A.","year":"1991","unstructured":"Houston A, Craig A. Perceptual and statistical analysis of cardiac phase and amplitude images. Eur3r Nucl Med 1991; 18: 720-4.","journal-title":"Eur3r Nucl Med"},{"key":"ref_15","first-page":"575","article-title":"Specificity and sensitivity of objective diagnosis of gastroesophageal reflux disease","volume":"102","author":"Fuchs, K.H.; DeMeester, T.R.; Albertucci, M.","year":"1987","unstructured":"Fuchs KH, DeMeester TR, Albertucci M. Specificity and sensitivity of objective diagnosis of gastroesophageal reflux disease. Surgery 1987; 102: 575-80.","journal-title":"Surgery"},{"key":"ref_16","first-page":"1160","article-title":"The role of prolonged esophageal pH monitoring in the diagnosis of gastroesophageal reflux","volume":"252","author":"Fink, S.M.; McCallum, R.W.","year":"1984","unstructured":"Fink SM, McCallum RW. The role of prolonged esophageal pH monitoring in the diagnosis of gastroesophageal reflux. J3AMA 1984; 252: 1160-4."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1145","DOI":"10.1136\/gut.28.9.1145","article-title":"Ambulatory 24 hour intraoesophageal pH monitoring in the diagnosis of gastrooesophageal reflux disease","volume":"28","author":"Johnsson, F.; Joelsson, B.; Isberg, P.E.","year":"1987","unstructured":"Johnsson F, Joelsson B, Isberg PE. Ambulatory 24 hour intraoesophageal pH monitoring in the diagnosis of gastrooesophageal reflux disease. Gut 1987; 28: 1145-50.","journal-title":"Gut"},{"key":"ref_18","first-page":"421","article-title":"Revelations about ambulatory esophageal pH monitoring","volume":"94","author":"Shaker, R.; Helm, J.F.; Dodds, W.J.; Hogan, W.J.","year":"1988","unstructured":"Shaker R, Helm JF, Dodds WJ, Hogan WJ. Revelations about ambulatory esophageal pH monitoring. Gastroenterology 1988; 94: A421.","journal-title":"Gastroenterology"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1016\/S0002-9610(88)80123-5","article-title":"Computerized ambulatory esophageal pH monitoring in 50 asymptomatic volunteer subjects. Results and clinical implications","volume":"155","author":"Cheadle, W.G.; Vitale, G.C.; Sadek, S.A.; Cuschierie, A.","year":"1988","unstructured":"Cheadle WG, Vitale GC, Sadek SA, Cuschierie A. Computerized ambulatory esophageal pH monitoring in 50 asymptomatic volunteer subjects. Results and clinical implications. Am] Surg 1988; 155: 503-8.","journal-title":"Am] Surg"},{"key":"ref_20","first-page":"797","article-title":"Limitations of 24-hour intraesophageal pH monitoring","volume-title":"the hospital setting. Gastroenterology 1985; 89","author":"Schlesinger, P.K.; Donahue, P.E.; Schmid, B.; Layden, T.J.","unstructured":"Schlesinger PK, Donahue PE, Schmid B, Layden TJ. Limitations of 24-hour intraesophageal pH monitoring in the hospital setting. Gastroenterology 1985; 89: 797-804."},{"key":"ref_21","first-page":"724","article-title":"Computerized 24-hour esophageal pH monitoring anld esophagogastroduodenoscopy in the reflux patient. A comparative study","author":"Vitale, G.C.; Cheadle, W.G.; Sadek, S.; Michel, M.E.; Cuschieri, A.","year":"1984","unstructured":"Vitale GC, Cheadle WG, Sadek S, Michel ME, Cuschieri A. Computerized 24-hour esophageal pH monitoring anld esophagogastroduodenoscopy in the reflux patient. A comparative study. Ann Surg 1984; 200: 724-8."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1080\/00365521.1990.12067095","article-title":"Ambulatory 24 hour pH-metry in the diagnosis of gastroesophageal reflux disease. Determination of criteria and relation to endoscopy","volume":"25","author":"Masclee, A.A.M.; de Best, A.C.A.M.; de Graaf, R.; Cluysenaer, O.J.J.; Jansen, J.B.M.J.","year":"1990","unstructured":"Masclee AAM, de Best ACAM, de Graaf R, Cluysenaer OJJ, Jansen JBMJ. Ambulatory 24 hour pH-metry in the diagnosis of gastroesophageal reflux disease. Determination of criteria and relation to endoscopy. Scand J Gastroenterol 1990; 25: 225-30.","journal-title":"Scand J Gastroenterol"},{"issue":"53","key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/lary.1991.101.s53.1","article-title":"The otolaryngologic manifestations of gastroesophageal refiux disease (GERD): a clinical investigation of 225 patients using ambulatory 24-hour pH monitoring and an experimental investigation of the role of acid and pepsin in the development of laryngeal injury","volume":"101","author":"Koufman, J.A.","year":"1991","unstructured":"Koufman JA. The otolaryngologic manifestations of gastroesophageal refiux disease (GERD): a clinical investigation of 225 patients using ambulatory 24-hour pH monitoring and an experimental investigation of the role of acid and pepsin in the development of laryngeal injury. Laryngoscope 1991; 101 (suppl 53): 1-78.","journal-title":"Laryngoscope"},{"key":"ref_24","first-page":"38","article-title":"Ambulatory esophageal and hypopharyngeal pH monitoring in patients with hoarseness","volume":"85","author":"P0, Katz","year":"1990","unstructured":"Katz P0. Ambulatory esophageal and hypopharyngeal pH monitoring in patients with hoarseness. Am]Z Gastroenterol 1990; 85: 38-40."}],"container-title":["Gut"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/gut.35.3.304","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,13]],"date-time":"2025-12-13T09:15:03Z","timestamp":1765617303000},"score":1,"resource":{"primary":{"URL":"https:\/\/gut.bmj.com\/lookup\/doi\/10.1136\/gut.35.3.304"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1994,3]]},"references-count":24,"journal-issue":{"issue":"3","published-online":{"date-parts":[[1994,3,1]]},"published-print":{"date-parts":[[1994,3]]}},"alternative-id":["10.1136\/gut.35.3.304"],"URL":"https:\/\/doi.org\/10.1136\/gut.35.3.304","relation":{},"ISSN":["0017-5749","1468-3288"],"issn-type":[{"value":"0017-5749","type":"print"},{"value":"1468-3288","type":"electronic"}],"subject":[],"published":{"date-parts":[[1994,3]]}}}