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

OBJECTIVE

To evaluate the performance of a near patient test for Helicobacter pylori infection in primary care.

DESIGN

Validation study performed within a randomised trial of four management strategies for dyspepsia.

SETTING

43 general practices around Nottingham.

SUBJECTS

394 patients aged 18-70 years presenting with recent onset dyspepsia.

MAIN OUTCOME MEASURES

Results of the FlexSure test compared with an enzyme linked immunosorbent assay (ELISA; HM-CAP) with an identical antigen profile and with results of an earlier validation study in secondary care. Diagnostic 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 specificity of 67% (95% confidence interval 59% to 75%) and 98% (95% to 99%) compared with a sensitivity and specificity of 92% (87% to 97%) and 90% (83% to 97%) when used previously in secondary care. Of the H pylori test and refer group 14% (28/199) were found to have conditions for which H pylori eradication was appropriate compared with 23% (39/170) of the group referred directly 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 incorporated into management policies for dyspepsia.