Serum antibodies anti‐H. pylori and anti‐CagA: A comparison between four different assays

摘要

The authors compare efficacy of two ELISA assays (one supplied by DIAMEDIX [Delta Biological s.r.l.], and the other by RADIM [RADIM I]) in detecting total anti‐ antibodies, and of two further ELISA methods (one supplied by EUROSPITAL [Helori CTX IgG] and the other by RADIM [RADIM 2]) in identifying anti‐CagA antibodies, using sera from 69 controls (20 adults and 49 children) and from 96 patients, obtained before endoscopy. Seventy‐three of the patients had infection, while the remaining 23 were negative (histology and polymerase chain reaction [PCR]). Fifty‐two of the positive patients, had cagA‐positive strain infection, identified by PCR. The DIAMEDIX assay was found to be more sensitive (92%) than RADIM 1 (79%) in identifying positive patients, irrespective of the infecting strain. On the other hand, the DIAMEDIX assay was less specific than RADIM 1 for ‐negative patients (43% vs. 83%). However, when patients already treated for infection were excluded from the group of ‐negative patients, the DIAMEDIX assay had a specificity of 89%. In identifying anti‐CagA antibodies, the kit supplied by RADIM (RADIM 2) had a sensitivity of 90% and a specificity of 94%, whereas that supplied by EUROSPITAL had a sensitivity of 100% and a specificity of 76%. The performances of the two methods in the identification of anti‐CagA antibodies were found to be similar. The authors conclude that, in view of its high sensitivity, the DIAMEDIX assay may be useful in screening for infection. J. Clin. Lab. Anal. 13:194–198, 1999. © 1999 Wiley‐Liss, Inc.