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Anti-DNase B

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

How the Test is Performed

A blood sample is drawn from a vein.

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, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

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. This means:

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

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

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 light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)


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



Bisno AL, Stevens DL. Streptococcus pyogenes. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill-Livingstone; 2009:chap 198.

Low DE. Nonpneumococcal streptococcal infections, rhematic fever. In: Goldman L, Schafer Al, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 298.

Update Date 5/19/2013

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