Detection of antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis: a comparison of the alkaline phosphatase and immunofluorescent techniques

Abstract

This study shows that the IALP method of ANCA detection is at least as sensitive as IF for the serological diagnosis of PSC. Indeed, combining data from all four centres, the IALP technique was significantly more sensitive than IF. We therefore recommend the use of the IALP technique, which is also easier to interpret and does not require the use of a specialist fluorescent microscope. The lack of a wide variation in sensitivity between IALP and IF for any individual patient group reported in this study suggests that the previously reported regional differences in ANCA prevalence in PSC of between 26% and 85% may be patient, related, rather than due to ethnic or methodological differences in ANCA detection, perhaps reflecting possible disease heterogeneity within PSC, or case selection bias. Further studies are needed to investigate this intriguing possibility. Such differences, if confirmed, will need to be taken into account when assessing the use of ANCA as a serological marker of PSC.