Antibody levels against B. pertussis in neonates measured in dried blood spots.

AIM: We designed this study to investigate if immunoglobuline G-Pertussis toxin (IgG-PT) against Bordetella pertussis in umbilical cord blood can reliably be determined in dried blood spots on filter paper (Guthrie) cards. PATIENTS AND METHODS: We prospectively included 129 mothers and their newborns born in a general hospital in the Netherlands. The relation between IgG-PT against B. pertussis from the umbilical cord measured in dried blood spots (Guthrie card) and in serum samples was studied by means of a Bland-Altman graph, using regression analysis to evaluate the level of agreement of both measurement methods. RESULTS: IgG-PT in Guthrie cards show a high coefficient of correlation with IgG-PT in serum samples from the umbilical cord when calibrated against blood spot calibrators (p<0.05). CONCLUSION: Maternal IgG-PT against B. pertussis measured in cord blood applied to Guthrie cards and calibrated against blood spot calibrators show good agreement with measurement of IgG-PT in cord serum. This offers new perspectives for future studies concerning B. pertussis antibodies.