Appropriateness of antineutrophil cytoplasmic antibody testing in a tertiary hospital.

AIMS

To determine whether indications for ordering antineutrophil cytoplasmic antibodies (ANCA) meet the 1999 guidelines proposed for ANCA testing; and to examine the test characteristics of the ANCA test.

METHODS

The indications for all ANCA tests over a two-year period were assessed and compared to the 1999 guidelines for the appropriate testing of ANCA.

RESULTS

1127 tests were examined. Overall 33.4% had an indication meeting the 1999 guidelines. The commonest non-guideline indications were ocular or orbital inflammation, liver disease and inflammatory bowel disease. All tests with a positive ANCA had indications for testing in line with the 1999 guidelines. In all but one case an ANCA associated small vessel vasculitis (AASVV) was present.

CONCLUSIONS

ANCA is ordered for a wide range of guideline and non-guideline indications. No cases of AASVV would have been missed if ordering were restricted to tests meeting the 1999 guidelines.