Antistrep-O Titer, Serum
Use
The Antistrep-O Titer test is useful for demonstrating acute or recent streptococcal infection, specifically group A streptococcal infections. These infections can lead to nonpurulent complications such as rheumatic fever and glomerulonephritis. The test helps in identifying elevated titers indicative of prior infection, which may have occurred asymptomatically during a latency period.
Special Instructions
Patients with acute glomerulonephritis following skin infection may have a reduced immune response to streptolysin O. In such cases, performing an alternative antibody test like Anti-DNase B Titer is recommended for better sensitivity. Fasting for 8 hours is preferred but not mandatory before specimen collection.
Limitations
The ASO test may not always diagnose acute group A streptococcal infections, particularly if the patient has been on antibiotics that could result in a negative culture. False-high titers can occur if sera are contaminated with bacterial organisms during shipment or storage, or in patients with liver disease due to high lipoprotein concentrations in the serum. Approximately 15% of individuals with rheumatic fever may not show elevated ASO titers, as these responses are not universal across all individuals with the infection. Skin infections often result in a poor ASO response, making alternative tests necessary for accurate results.
FDA ApprovedNew York Approved
Methodology
Immunoassay (Nephelometry)
Biomarkers
LOINC Codes
- 5370-2
- 5370-2
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Serum gel or red top tube; transfer to plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial.
Patient Preparation
Fasting for 8 hours preferred but not required
Causes for Rejection
Gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 28 days |
| Frozen | 28 days |