Document exposure to Streptococcal streptolysin O
Immediatley following collection, mix sample by gently inverting 5 times
Gold serum separator (SST) tube
Ambient (preferred) - 14 days
Refrigerated - 14 days
Frozen - 14 days
Freeze/thaw cycles - stable x 3
Latex immunoturbidimetry
0.0 - 200.0 IU/mL
A marked rise in titer or a persistently elevated titer indicates that a Streptococcus infection or poststreptococcal sequelae are present. Streptolysin is a hemolysin produced by group A streptococci. In an infected individual streptolysin O acts as a protein antigen, and the patient mounts an antibody response. A rise in antibody level begins about 1 week after infection and peaks 2-3 weeks later. In the absence of complications or reinfection, the ASO titer will usually fall to preinfection levels within 6-12 months. Both clinical and laboratory findings should be correlated in reaching a diagnosis.