Agglutination of sensitized sheep cells
Aid in the diagnosis of current or previous group A streptococcal infections. Screening for antibodies to streptococcal antigens NADase, DNAase, streptokinase (ASK), streptolysin O (ASO) and hyaluronidase (AH): Positive test titered to 1:800; endpoint beyond 1:800 reported as > 1:800.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
The value of a single determination is limited. Sequential determinations may give the trend in antibody production and allow clinical conclusions with regard to the progress of the disease and treatment. False negatives may be found in patients with decreased immune response. Since there is a 30% false negative Streptozyme incidence in sera which have only a slight elevation of a single antibody titer, the Streptozyme test could miss a borderline streptococcal antibody titer. Test Sensitivity: < 1:100.
Days Test Performed
Monday - Friday
Soft Order Code
ASO (Anti-Streptolysin O)
Streptolysin O Antibody
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Offsite Collection Instructions
Collect specimen in SST tube. Centrifuge, aliquot serum into a plastic vial and freeze at -20C
0.5 mL serum
0.3 mL serum
Antibodies to streptococcal A exoenzymes may develop in rheumatic fever, glomerulonephritis, bacterial endocarditis, scarlet fever, and other related conditions. The most conclusive data is an increase in titer on successive specimens taken several days apart. Antibodies increase 1-3 weeks after onset and decrease 8-10 weeks after uncomplicated infection. Approximately 80% of Streptozyme positive sera have an ASO of 166 IU or above while an additional 10% showed an ASK or AH also above 166 IU. The remaining 10% agglutination may be due to antibodies to other streptococcal exoenzymes or to the combined effect of several antibodies which individually would fall below 166 IU. The accuracy of the test in patients with streptococcals infection is 95% and correlates well in patients with streptococcal pyoderma and poststreptococcal kidney involvement.