Wanneer is het kinkhoest? Verband tussen laboratoriumdiagnostische bevindingen en klachten

– The relationship between the occurrence of whooping cough complaints and positive laboratory findings was investigated. Data concerning persons (n = 422) examined for whooping cough by the Municipal Health Service of Amsterdam were studied retrospectively. The diagnostic procedure included cultures from nasopharyngeal swabs in 194 cases and serological determination of pertussis-specific IgA- and IgG-a-LPF antibodies in 329 cases. 180 patients showed a positive laboratory result (culture andor serological confirmation positive).

There is no evidence of a clear relationship between laboratory findings and complaints. This could possibly be explained if the probability of developing symptoms were connected with the immunity status of infected persons, for instance, high levels of immunity leading to serological evidence of infection but not to complaints. The cases with complaints but without laboratory evidence remain unexplained however. Age turned out to be a confounding factor with respect to the serodiagnosis: older persons are more likely to have positive findings.

The value and present use of laboratory findings for the confirmation of the diagnosis of whooping cough are questioned. More research into the relationship between symptoms and laboratory tests is recommended.