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Anti-DNase B blood test

Anti-DNase B is a blood test to look for antibodies to a substance (protein) produced by group A streptococcus. This is the bacteria that cause strep throat.

When used together with the ASLO titer test, more than 90% of past streptococcal infections can be correctly identified.

How the Test is Performed

How to Prepare for the Test

No special preparation is necessary.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

This test is most often done to tell if you have previously had a strep infection and if you might have rheumatic fever or kidney problems (glomerulonephritis) due to that infection.

Normal Results

A negative test is normal. Some people have low concentrations of antibodies, but they have not had a recent strep infection. Therefore, normal values in different age groups are:

  • Adults: less than 85 units/milliliter (mL)
  • School-age children: less than 170 units/mL
  • Preschool children: less than 60 units/mL

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

Increased levels of DNase B levels indicate exposure to group A streptococcus.

Risks

Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks:

  • Excessive bleeding
  • Fainting or feeling lightheaded
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

Alternative Names

Strep throat - anti-DNase B test; Antideoxyribonuclease B titer; ADN-B test

Images

References

Bryant AE, Stevens DL. Streptococcus pyogenes. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 199.

Chernecky CC, Berger BJ. Antideoxyribonuclease B antibody titer (anti-DNase B antibody, streptodornase) – serum. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. Philadelphia, St Louis, MO: Elsevier Saunders; 2013:145.

Review Date 5/18/2017

Updated by: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.