Anti-DNase B blood test

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Anti-DNase B is a blood test to look for antibodies to a substance produced by Group A Streptococcus. This is the bacteria that causes strep throat.

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

Alternative Names

Antideoxyribonuclease B titer; ADN-B test

How the Test is Performed

A blood sample is needed.

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

or kidney problems () due to that infection.

Normal Results

A negative test is normal. However, people with low concentrations of antibodies also likely do not have a recent strep infection. This means:

  • 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 doctor about the meaning of your specific test results.

What Abnormal Results Mean

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


Veins and arteries vary in size from one patient 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)



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. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 199.

Hall GS, Woods GL. Medical bacteriology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 57.

Version Info

  • Last reviewed on 5/1/2015
  • 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, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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