Antistreptolysin O (ASLO)

General Information

Antistreptolysin O

Antistreptolysin O (ASLO) is an antibody that the body produces Group A beta-hemolytic streptococcus (Streptococcus pyogenes) In response to streptolysin-O toxin produced by Streptococcus pneumoniae. The test is used to confirm a recent streptococcal infection and to assess its possible complications.

Streptolysin is a hemolytic toxin produced by group A streptococcus. In infected patients, streptolysin acts as an antigen against which the body produces specific antibodies – O antistreptolysins. An increase in the concentration of antistreptolysin antibodies indicates the body's sensitization to streptococcal antigens. The increase in the concentration of ASL-O begins 1 week after the diagnostics of streptococcal infection and its level reaches a maximum in 2-4 weeks. In the absence of complications or recurrence of infection, the level of ASL-O returns to normal after 6-12 months.

A persistent increase in antistreptolysin O levels increases the risk of developing rheumatoid diseases. During the convalescence period, the indicator decreases compared to the acute period. Serial testing (approximately 1-2 weeks apart) has the greatest diagnostic and prognostic value. ASL-O titer can also be increased in healthy carriers of streptococci.