Days Set Up
Daily, 24 hrs
Analytic Time

2 hours

MiChart Code
Antistreptolysin O
Soft Order Code

Test Updated:


Antistreptolysin O Antibody
ASO (Anti-Streptolysin O)
Streptolysin O Antibodies

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All specimens should be accompanied by a requisition.

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Test Overview

Test Methodology


Test Usage

Document exposure to group A streptococcal antigen, particularly streptolysin O. A marked rise or persistently elevated level indicates that a focus of streptococcal infection or poststreptococcal sequelae is present. Over 80% of patients with acute rheumatic fever and over 95% of patients with acute glomerulonephritis have elevated ASO levels.

Reference Range

< 5 years: 0-99 IU/ml; 5-15 years: 0-249 IU/ml; Adult: 0-199 IU/ml

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

Collect specimen in an SST tube. Cause for Rejection: Grossly lipemic (triglyceride levels greater than 900 mg/dl)samples are not recommended for analysis.

Collection Offsite

Collect specimen in an SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate up to 48 hours or freeze for longer storage.

Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.25 mL serum

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.