How does anti-DNase B differ from ASO?

ASO detects antibodies to streptolysin O and is more sensitive after pharyngitis; anti-DNase B is more sensitive after skin infection and remains elevated longer. Dual testing captures over 90 per cent of recent streptococcal infections and is recommended when a single marker is negative but clinical suspicion remains.

When should anti-DNase B be ordered?

Order it when acute rheumatic fever or post-streptococcal glomerulonephritis is suspected — particularly if the antecedent infection was a skin infection such as impetigo — and when ASO is negative or borderline but recent streptococcal infection remains clinically likely.

Does a positive anti-DNase B result mean active infection?

No. A positive result indicates recent infection within the preceding weeks to months, not active bacterial infection. Group A streptococci are typically cleared by the time antibodies peak. Clinical correlation is essential to determine whether the elevated titre explains a post-streptococcal sequela.

Can the test be negative if infection occurred?

Yes. If the specimen is drawn too early (within the first week) or if early antibiotic treatment blunted the response, titres may be negative. Repeating serology two weeks later to capture a rising titre improves diagnostic sensitivity.

Why are paediatric reference ranges higher?

Children experience frequent group A streptococcal exposures, sustaining higher baseline and upper-limit titres than adults. Age-specific thresholds prevent over-diagnosis of recent infection in children with endemic exposure.

Is fasting required for this test?

No. Anti-DNase B is measured in serum and does not require fasting or special patient preparation.

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Anti-DNase B (Streptococcal) Antibodies

Q: What is anti-DNase B and why is it measured?

Anti-DNase B is an antibody to an enzyme produced by group A streptococci. It is measured to confirm recent streptococcal infection when a post-streptococcal complication such as acute rheumatic fever or glomerulonephritis is suspected, especially after the organism is no longer present in throat or skin.

Q: How long does anti-DNase B remain elevated?

Titres typically peak four to six weeks after infection and then decline slowly over several months. A persistently elevated titre after documented infection is common and does not indicate recurrent or ongoing disease without compatible clinical features.

The Anti-DNase B test measures serum antibodies to an extracellular deoxyribonuclease enzyme of group A streptococci, providing serological evidence of recent infection. Titres rise within one to two weeks and peak at four to six weeks; the response is particularly robust after skin infection.

Biomarkers

Blood (serum)

Sample

2–4 business days

Turnaround

Fasting

What is the Anti-DNase B test?

The Anti-DNase B test detects antibodies to an extracellular enzyme of group A streptococci, offering serological proof of recent infection when the organism is no longer recoverable from the throat or skin. Practitioners order it almost exclusively in the context of suspected post-streptococcal immune-mediated complications — acute rheumatic fever and acute post-streptococcal glomerulonephritis — where establishing temporal association with a streptococcal infection is a diagnostic prerequisite. Anti-DNase B complements rather than replaces the anti-streptolysin O (ASO) assay: ASO is more sensitive after pharyngitis, while anti-DNase B is more sensitive after skin infection and remains elevated longer. Dual testing increases the cumulative sensitivity for detecting recent infection to well above 90 per cent, so when a post-streptococcal sequela is suspected and ASO is normal or equivocal, anti-DNase B often resolves the diagnostic uncertainty.

What does the Anti-DNase B test measure?

Anti-DNase B(Anti-Deoxyribonuclease B Antibody)

Range: Typically <170–340 U/mL or titre <1:170 in adults; paediatric thresholds higher (often <480 U/mL). Assay-specific.Optimal: Reference laboratories report positive or elevated when the titre exceeds the age-specific upper limit; there is no single 'optimal' healthy value, and a negative result is expected in the absence of recent streptococcal infection.titre (dilution) / U/mL

Deoxyribonuclease B is an extracellular deoxyribonuclease enzyme produced by group A streptococci (Streptococcus pyogenes). During and after pharyngeal or cutaneous infection, the host mounts a specific antibody response to DNase B; titres rise within one to two weeks of infection, peak at four to six weeks, and then decline slowly over months. The response is particularly robust following skin infection (pyoderma, impetigo), where anti-streptolysin O (ASO) may be weak or absent because lipid-rich skin inactivates streptolysin O.

Anti-DNase B antibodies are serological evidence of recent group A streptococcal infection. Clinicians order the test when a post-streptococcal sequela — acute rheumatic fever or acute post-streptococcal glomerulonephritis — is suspected and to corroborate a streptococcal aetiology in patients with a negative or borderline ASO. Because the antibody response is more reliable after skin infection, anti-DNase B is especially useful for glomerulonephritis cases following impetigo, and dual testing (ASO plus anti-DNase B) captures the majority of true streptococcal exposures.

Why is the Anti-DNase B test ordered?

Investigation of suspected acute rheumatic fever in a patient presenting with migratory polyarthritis, carditis, chorea, erythema marginatum, or subcutaneous nodules, to fulfil the Jones criteria for recent streptococcal infection
Evaluation of acute post-streptococcal glomerulonephritis when haematuria, proteinuria, oedema, and hypertension appear one to three weeks after a skin or throat infection, particularly if that infection was pyoderma
Patients with a negative or borderline ASO titre in whom a post-streptococcal aetiology remains clinically suspected, to improve diagnostic sensitivity
Serial follow-up of confirmed post-streptococcal disease, though falling titres are expected and a persistently elevated titre alone does not imply ongoing active disease
Outbreak or epidemiological investigation of group A streptococcal infections in institutional or close-contact settings, when throat culture is no longer practical
Paediatric cases where skin infection predominates, since ASO may be falsely negative after impetigo

Sample collection and turnaround

Sample type

Blood (serum)

Fasting required

Collection method

Venipuncture at patient service centre

Turnaround

2–4 business days

Collection notes

Phlebotomy at LabCorp draw site; no special preparation. When acute rheumatic fever or glomerulonephritis is suspected, collect the specimen as soon as possible after presentation, and consider a convalescent specimen two weeks later if the initial result is equivocal, to demonstrate a rising titre.

Specimen requirements

Minimum 0.5 mL serum. Separate from cells promptly; stable refrigerated for up to one week or frozen for longer storage. Submit alongside or shortly after an ASO specimen for dual streptococcal serology.

What can affect Anti-DNase B results?

variableTiming of the specimen relative to infection

Titres begin rising one to two weeks after infection, peak at four to six weeks, and decline over months; a specimen drawn too early in the acute phase may be falsely negative, while one drawn months later may have returned to baseline.

elevatesPrior streptococcal infections and re-exposure

Repeated group A streptococcal exposure, especially in children in crowded settings, can sustain a moderately elevated titre without current disease, so clinical correlation is essential.

reducesAntibiotic treatment of the antecedent infection

Early antibiotic therapy may blunt or delay the antibody response, though titres usually still rise; a negative result does not exclude infection if treatment was prompt.

elevatesAge and background streptococcal exposure

Children and adolescents have higher baseline and upper-limit thresholds than adults because of frequent streptococcal exposures; reference ranges must be age-adjusted.

elevatesSkin versus pharyngeal streptococcal infection

Anti-DNase B response is particularly strong and sustained after skin infection (impetigo, pyoderma), whereas ASO may be weak because skin lipids inactivate streptolysin O; this makes anti-DNase B the preferred marker for post-impetigo glomerulonephritis.

What do Anti-DNase B results mean?

Elevated

An elevated or rising titre is serological evidence of recent group A streptococcal infection within the preceding weeks to months. In the appropriate clinical context — migratory arthritis, carditis, glomerulonephritis, low complement, erythema marginatum — it supports a diagnosis of acute rheumatic fever or post-streptococcal glomerulonephritis. A single elevated titre indicates exposure but not necessarily active disease; clinical correlation, timing, and the presence of compatible sequelae are required for diagnosis.

Normal

A normal or negative anti-DNase B in the setting of suspected post-streptococcal disease makes recent infection less likely but does not exclude it, especially if ASO is also negative and clinical suspicion is high. In that situation consider repeat serology in one to two weeks to capture a rising titre, or review the clinical diagnosis.

Reduced

A titre below the laboratory threshold is interpreted as negative and indicates no serological evidence of recent streptococcal infection. It does not, however, exclude infection if the specimen was drawn too early (first week) or if the patient received early antibiotic treatment that blunted the response.

Note: Anti-DNase B must be interpreted with the timing of the suspected infection, the clinical syndrome, and the ASO result. Dual testing (ASO plus anti-DNase B) achieves the highest sensitivity. A persistently elevated titre after documented infection is common and does not itself indicate recurrent or ongoing disease. Reference limits differ by age, assay, and laboratory, so note the performing lab for serial comparisons.

Frequently asked questions

Anti-DNase B is an antibody to an enzyme produced by group A streptococci. It is measured to confirm recent streptococcal infection when a post-streptococcal complication such as acute rheumatic fever or glomerulonephritis is suspected, especially after the organism is no longer present in throat or skin.

How to access the Anti-DNase B test

The Anti-DNase B reference page is free and open to all practitioners. Create a free practitioner account to see pricing, save tests to your list, and generate requisition forms. Verification takes 1–2 business days.

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About this page

Published: October 7, 2026

Last reviewed: October 7, 2026

References:

Gerber MA, et al. Prevention of rheumatic fever and diagnosis and treatment of acute streptococcal pharyngitis: a scientific statement from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee. (2009)
Carapetis JR, et al. Acute rheumatic fever. Lancet. (2005)
Rodriguez-Iturbe B, Musser JM. The current state of poststreptococcal glomerulonephritis. J Am Soc Nephrol. (2008)
Ayoub EM, Wannamaker LW. Evaluation of the streptococcal deoxyribonuclease B and diphosphopyridine nucleotidase antibody tests in acute rheumatic fever and acute glomerulonephritis. Pediatrics. (1962)

This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.