Use

Antibody levels above the reference range are highly suggestive of recent infection or vaccination. The PT antibody assay aids in diagnosis of Bordetella pertussis infection in patients with a persistent cough lasting more than 2 to 3 weeks. However, PT antibody results cannot be used to assess protective immunity, as the antibody levels that correlate with protection have not been well defined. PT IgG is preferred for identifying recent infection in individuals of all ages, with sensitivities and specificities >92%. PT IgA may be useful in children <10 years to distinguish infection versus vaccination.