Antistreptolysin O (ASO) Antibodies
Use
The test is used to document exposure to streptococcal streptolysin O. A significant rise in the ASO titer or a persistently elevated titer indicates a current or past infection with Streptococcus, or poststreptococcal sequelae. ASO levels help in diagnosing and managing diseases caused by Group A Streptococcus infections, particularly rheumatic fever and glomerulonephritis.
Special Instructions
The ASO titer begins to rise approximately one week after infection and peaks in two to three weeks. Without complications or reinfection, the ASO levels typically return to preinfection levels within 6 to 12 months. Clinical evaluation should be correlated with laboratory findings for an accurate diagnosis.
Limitations
False-positive results can occur due to elevated serum β-lipoprotein levels seen in liver disease, or contamination of the serum with Bacillus cereus and Pseudomonas species. Although ASO titers are elevated in about 85% of rheumatic fever patients, they may not be elevated in cases involving skin or renal sequelae. For such conditions, the anti-DNase B test may be a more suitable option. It is important to correlate ASO titer results with clinical presentations and other diagnostic procedures.
Methodology
Immunoassay (Other)
Biomarkers
LOINC Codes
- 5370-2
- 5370-2
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
0.5 mL
Container
Red-top tube or gel-barrier tube
Storage Instructions
Room temperature
Causes for Rejection
Gross hemolysis; lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |