[Reference values of antistreptolysin O and asymptomatic carriers of β-hemolytic streptococci in adolescents and adults at Municipality Francisco Linares Alcántara, Venezuela].

INTRODUCTION: β-hemolytic streptococci (Streptococcus pyogenes) groups A, C or G, secretes streptolysin O, toxin which causes in the infected individual an adaptive humoral immune response with production of serum antibodies called anti-streptolysin O (ASO).

OBJECTIVES: To determine the reference value of ASO in a sample of 159 individuals aged 16-72 years from municipality Francisco Linares Alcántara, Aragua state, applying indirect (passive) agglutination test. By using a throat swab sample which was sown in blood agar 5% the frequency of asymptomatic carriers of β-hemolytic streptococci was also determined.

RESULTS AND DISCUSSION: As reference value for determining ASO by agglutination method a title of up to 200 IU/mL was obtained, this reference value differs from that recommended by the commercial equipment. Asymptomatic carriers frequency was 21.2% (n = 34). The distribution of β-hemolytic streptococci isolated were: group A (17.6%), group B (32.3%), group C (20.5%), group D (2.9%), group F (8.8%), group G (14.7%) and unclusterable (2.9%).

CONCLUSIONS: The new ASO reference value for teens and adults of the mentioned municipality is up to 200 IU/mL. β-hemolytic Streptococcus group B was the most frequently isolated.