Testing for Helicobacter pylori infection: validation and diagnostic yieldof a near patient test in primary care

Objective To evaluate the performance of a near patient test for Helicobact er pylori infection in primary care. Design Validation study performed within a randomised trial of four managem ent strategies for dyspepsia. Setting 43 general practices around Nottingham. Subjects 394 patients aged 18-70 years presenting with recent onset dyspeps ia. Main outcome measures Results of the FlexSure test compared with an enzyme linked immunosorbent assay (ELISA; HM-CAP) with an identical antigen profil e and with results of an earlier validation study in secondary care. Diagno stic yield of patients undergoing endoscopy on the basis of their FlexSure result compared with those of patients referred directly for endoscopy. Results When used in primary care FlexSure test had a sensitivity and speci ficity of 67% (95% confidence interval 59% to 15%) and 98% (95% to 99%) com pared with a sensitivity and specificity of 92% (87% to 97%) and 90% (83% t o 97%) when used previously in secondary care. Of the H pylori test and ref er group 14% (28/199) were found to have conditions for which H pylori erad ication was appropriate compared with 23% (39/170) of the group referred di rectly for endoscopy. Conclusions When used in primary care the sensitivity of the FlexSure test was significantly poorer than in secondary care. About a third of patients who would have benefited from H pylori eradication were not detected. Near patient tests need to be validated in primary care before they are incorpor ated into management policies for dyspepsia.