RESUMEN
BACKGROUND: Antistreptolysin O (ASO) is very useful as an indicator of recent streptococcal infection and its sequelae, such as rheumatic fever and acute glomerulonephritis. Because the upper limit of normal (ULN) value of ASO varies according to age, the ULN value of ASO in an area should be evaluated to accurately interpret single ASO levels of patients. METHODS: The ULN value and distribution of ASO concentrations were investigated in three age groups of preschool children (N=162), elementary school children (N=436), and adults (N=231) in Chinju. ASO concentra-tions were measured quantitatively by autoanalyzer or nephelometer from sera of healthy population in Chinju who had no symptoms or signs of streptococcal infec-tions. RESULTS: The mean(+/-SD) ASO concentrations were 71(+/-107) IU/mL, 285(+/-246) IU/mL, and 80(+/-64) IU/mL and the UNL value of ASO concentrations were 131 IU/mL, 433 IU/mL, and 136 IU/mL in each group of preschool children, elementary school children, and adults, respectively. CONCLUSION: The distribution and ULN value of ASO concentrations varied according to age group. The ULN value of ASO concentrations should be set differ-ently according to the patient' s age. Group A strepto-coccal infections might be quite common in elementary school children, while very rare in preschool children or adults.