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.
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.
- 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.
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
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. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial Team.