Anti-DNase B Antibody Test
🧪 Anti-DNase B Antibody Test — Complete Guide
1. Overview of Anti-DNase B Antibody Test
The Anti-DNase B (anti–deoxyribonuclease B) antibody test is essential for detecting immune response following Group A Streptococcus (GAS, Streptococcus pyogenes) infection.
Key points:
- Detects post-streptococcal complications such as:
- Acute Rheumatic Fever (ARF)
- Post-streptococcal Glomerulonephritis (PSGN)
- Complements ASO (Antistreptolysin O) testing, especially in cases where ASO may be negative (e.g., skin infections)
- Monitored by CDC and WHO for public health management
2. Test Purpose
- Detect recent Group A Streptococcus infection
- Tonsillitis, pharyngitis, or skin infection history
- Anti-DNase B rises 1–2 weeks post-infection, peaks at 4–6 weeks
- Assess post-streptococcal complications
- ARF, PSGN
- Useful even if initial infection was asymptomatic
- Combined assessment with ASO
- Enhances diagnostic sensitivity
- ASO more sensitive to pharyngeal infections
- Anti-DNase B more sensitive to skin infections
3. Specimen and Test Method (Nephelometry, NEP)
Specimen
- Serum
Test Principle: Nephelometry (NEP)
- Anti-DNase B antibodies in the patient serum bind to DNase B antigen, forming immune complexes
- Light scattering from complexes is measured → quantitative antibody concentration
Advantages:
- Rapid and automated
- High reproducibility
- Provides precise quantitative results
4. Reference Ranges (Typical Values)
| Age Group | Reference Range (U/mL) |
|---|---|
| <5 years | < 251 |
| 5–17 years | < 376 |
| ≥18 years | < 301 |
Repeat testing after 2–3 weeks can confirm rising titers, supporting recent infection. Values may vary by manufacturer and region.
5. Clinical Significance
- Recent GAS infection evidence
- Antibody rises 1–2 weeks post-infection, peaks at 4–6 weeks
- Can remain elevated for several months
- Diagnosis of post-streptococcal complications
- ARF and PSGN may occur even without obvious infection symptoms
- Anti-DNase B is critical for confirming recent exposure
- Complementary to ASO testing
- Skin infections (impetigo) often show ASO negative, Anti-DNase B positive
6. Situations Affecting Levels
High Values (Elevated)
- Recent GAS infection
- ARF
- PSGN
- Recovery phase after pharyngitis or skin infection
- Invasive streptococcal infections
Low or Normal Values
- Early infection (antibodies not yet formed)
- Certain GAS strains
- Severe immunodeficiency
- Declining antibody phase after months
7. Interpretation Considerations
- Not a standalone diagnostic test → indicates recent infection, not active infection
- Age-specific reference ranges → children may have higher baseline antibodies
- Combined testing with ASO → increases diagnostic accuracy
- Antibody decline is gradual → timing affects interpretation
- Chronic kidney disease or protein-losing conditions → may lower antibody levels, consider patient history
8. Summary Table
| Item | Key Points |
|---|---|
| Test Name | Anti-DNase B Antibody |
| Specimen | Serum |
| Test Method | Nephelometry (NEP) |
| Reference Range | <5 yr: <251 U/mL, 5–17 yr: <376 U/mL, ≥18 yr: <301 U/mL |
| Clinical Use | Detect recent GAS infection, post-streptococcal complications (ARF, PSGN), complement ASO testing |
| Limitations | Not for acute infection diagnosis; interpret with ASO, infection history, and clinical findings |
9. References
- CDC. Group A Streptococcal (GAS) Disease Guidelines
- Kaplan EL. “Antistreptococcal Antibody Tests in the Diagnosis of Post-Streptococcal Diseases.” Pediatrics Infect Dis J.
- Johnson DR, et al. “Laboratory diagnosis of streptococcal infections.” Clinical Microbiology Reviews
- WHO. Streptococcal disease laboratory recommendations