title: Evaluation of serological tests for diagnosis of Bordetella pertussis infection in adolescents and adults.
abstract: OBJECTIVE
  Bacterial agglutination antibodies against Bordetella pertussis, Yamaguchi and Tohama strains, are frequently measured for serodiagnosis of pertussis infection in Japan. To determine the serological criteria, the comparative titres of bacterial agglutination antibody and anti-pertussis toxin (PT) antibody were evaluated.
  
  
  METHODS
  Antibody titres were analysed in 36 definitive (fourfold increase in agglutination antibody) and 137 presumptive (high titre of single-antibody) cases of B. pertussis infection among adolescents and adults, and in a control group of 318 healthy volunteers.
  
  
  RESULTS
  When a single Yamaguchi agglutinin titre of ≥ 1:1280 (> three SD above the geometric mean for the control group) was taken as diagnostic, the sensitivity and specificity at 4-5 weeks after onset of cough were 58% and 98%, respectively. Using this criterion, the clinical findings in presumptive cases were almost identical to those in definitive cases. When the two tests were compared using 318 control sera, there was no association between the Tohama agglutinin titre and the anti-PT antibody titre, whereas a weak association between the Yamaguchi agglutinin titre and the anti-PT antibody titre was observed. When the numbers of pertussis cases with high antibody titres in the two tests were compared, 60% of cases with a Yamaguchi agglutinin titre of ≥1:1280 showed an anti-PT antibody titre of ≥100 EU/mL.
  
  
  CONCLUSIONS
  These results indicate that the bacterial agglutination test is a method with low sensitivity and specificity for the diagnosis of B. pertussis infection. Therefore, to yield an accurate diagnosis, anti-PT antibody levels should be measured instead of bacterial agglutination antibody.
authors.affiliation: Departments of Internal Medicine I             Pediatrics, Kawasaki Medical School, Okayama, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Miyashita
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kawai
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Ouchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000373:Agglutinins / Q000097:blood; D001886:Bordetella pertussis / Q000276:immunology / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D037342:Pertussis Toxin / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012698:Serologic Tests; D014917:Whooping Cough / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D055815:Young Adult
chemical_list: D000373:Agglutinins; D037342:Pertussis Toxin