title: [Reliability of the cut-off value in the routine serodiagnosis of pertussis performed by the commercial ELISA assays].
abstract: In clinical practise, serodiagnosis of pertussis is mostly based on single-sample serology using a single cut-off. The reliability of the cut-off value has the crucial influence for the sensitivity and specificity of the used tests. In this context we compared the value of cut-off used in two commercial ELISA kits (NovaLisa Bordetella pertussis-NovaTec and ELISA Bordetella pertussis ELISA-Virotech) with cut-off settled by calculation the IgA and IgG results from the 60 healthy Polish children and 100 blood donors (arithmetic mean plus 2 or 3 standard deviations). Our study indicates that IgA cutoff used in NovaTec ELISA, in contrary to Virotech ELISA, correspond better to the level x+3SD calculated in children sera and x+2SD calculated in adult blood donors sera. The value of IgG cut-off used in Virotech ELISA was lower about 20% and 30% from the cut-off settled by us respectively on the level ofx+2SD and x+3SD in all tested sera. The most inadequate value had the IgG cut-offused in NovaTec ELISA, which was over three times lower than mean cut-off value settled by calculation results from the sera obtained from healthy children and blood donors. This low cut-off value established by the NovaTec was the reason that 23.3% of healthy children and 55.0% of blood donors have the IgG antibodies on the diagnostic significant level. Our data suggest that commercial ELISAs need further improvement and standardization.
authors.affiliation: Zakład Bakteriologii NIZP-PZH w Warszawie.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Rastawicki
authors.forename: Iwona
authors.initials: I
authors.lastname: Paradowska-Stankiewicz
authors.forename: Paweł
authors.initials: P
authors.lastname: Stefanoff
authors.forename: Aleksandra A
authors.initials: AA
authors.lastname: Zasada
mesh_terms: D000328:Adult; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D015203:Reproducibility of Results; D012698:Serologic Tests / Q000379:methods*; D014917:Whooping Cough / Q000097:blood* / Q000175:diagnosis*