title: Normal ranges of streptococcal antibody titers are similar whether streptococci are endemic to the setting or not.
abstract: Group A streptococcal (GAS) serology is used for the diagnosis of post-streptococcal diseases, such as acute rheumatic fever, and occasionally for the diagnosis of streptococcal pharyngitis. Experts recommend that the upper limits of normal for streptococcal serology be determined for individual populations because of differences in the epidemiology of GAS between populations. Therefore, we performed a study to determine the values of the upper limit of normal for anti-streptolysin O (ASO) and anti-DNase B (ADB) titers in Fiji. Participants with a history of GAS disease, including pharyngitis or impetigo, were excluded. A total of 424 serum samples from people of all ages (with a sample enriched for school-aged children) were tested for their ASO and ADB titers. Reference values, including titers that were 80% of the upper limit of normal, were obtained by regression analysis by use of a curve-fitting method instead of the traditional nonparametric approach. Normal values for both the ASO titer and the ADB titer rose sharply during early childhood and then declined gradually with age. The estimated titers that were 80% of the upper limit or normal at age 10 years were 276 IU/ml for ASO and 499 IU/ml for ADB. Data from our study are similar to those found in countries with temperate climates, suggesting that a uniform upper limit of normal for streptococcal serology may be able to be applied globally.
authors.affiliation: Centre for International Child Health, University of Melbourne, Melbourne, Victoria, Australia. andrew.steer@rch.org.au
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Steer
authors.forename: Suzanna
authors.initials: S
authors.lastname: Vidmar
authors.forename: Roselyn
authors.initials: R
authors.lastname: Ritika
authors.forename: Joseph
authors.initials: J
authors.lastname: Kado
authors.forename: Michael
authors.initials: M
authors.lastname: Batzloff
authors.forename: Adam W J
authors.initials: AW
authors.lastname: Jenney
authors.forename: John B
authors.initials: JB
authors.lastname: Carlin
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Carapetis
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003851:Deoxyribonucleases / Q000276:immunology; D019353:Endemic Diseases; D005260:Female; D005367:Fiji / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000276:immunology*; D013301:Streptolysins / Q000276:immunology; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D013301:Streptolysins; C025964:streptolysin O; D003851:Deoxyribonucleases; C020069:deoxyribonuclease B