Overview: Anti-Streptolysin-O Titer TestIntroduction: The Anti-Streptolysin-O Titer Test detects antibodies to streptococcal infection, which may cause sore throat, fever, or complications like rheumatic fever. Aligned with 2023 IDSA guidelines, it uses an immunoassay for high sensitivity, aiding in infectious disease screening. This test is critical for guiding treatment, monitoring streptococcal complications, and improving outcomes in immunology for patients with suspected post-streptococcal conditions.
Other Names: ASO Titer Assay, Streptolysin-O Antibody Test.
FDA Status: Laboratory-developed test (LDT), meeting immunology standards for diagnostic accuracy.
Historical Milestone: Streptococcal antibody testing began in the 1950s with ASO titers. Immunoassays emerged in the 1970s, and by the 2000s, high-sensitivity methods improved detection of complications.
Purpose: Diagnoses streptococcal infections, guides treatment, and monitors complications like rheumatic fever in patients with sore throat or fever.
Test Parameters: 1. Anti Streptolysin O
Pretest Condition: No fasting required. Collect serum or saliva at any time, ideally after symptom onset. Report symptoms like sore throat or fever, and list medications like antibiotics.
Specimen: 2-5 mL serum (SST) or 1-2 mL saliva (sterile container). Centrifuge serum within 1 hour. Transport in a biohazard bag within 8 hours.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document streptococcal symptoms, recent infections, or family history of rheumatic fever. Include current medications, especially antibiotics or NSAIDs.
Consent: Written consent required, detailing the tests purpose, diagnostic implications, and potential need for treatment or further testing.
Procedural Considerations: Uses an immunoassay to measure ASO titers. Results are available in 1-2 days, enabling rapid clinical decisions.
Factors Affecting Result Accuracy: Recent antibiotic treatment may suppress antibody levels, causing false negatives. Hemolysis or improper storage can degrade samples.
Clinical Significance: Elevated ASO titers confirm recent streptococcal infection, prompting treatment for complications like rheumatic fever. Normal levels may require anti-DNase B testing.
Specialist Consultation: Consult an infectious disease specialist for result interpretation. A cardiologist referral is advised for rheumatic fever cases.
Additional Supporting Tests: Anti-DNase B test, throat culture, or echocardiogram to confirm streptococcal infection or assess complications.
Test Limitations: False negatives may occur with early infection or treatment. Results require clinical correlation with other streptococcal markers.
References: IDSA Streptococcal Guidelines, 2023; Clinical Infectious Diseases, Shulman ST, 2022.
