DefinitionAnti-DNase B is a blood test to look for antibodies to a substance produced by Group A Streptococcus, the bacteria that cause strep throat.See also:ASLO titerStrep throatStreptococcal screen
Alternative NamesAntideoxyribonuclease B titer; ADN-B test
How the test is performedA blood sample is needed. For information on how this is done, see: Venipuncture.
How to prepare for the testNo special preparation is necessary.
How the test will feelWhen 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 performedThis 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 ValuesA negative test is normal. This means:Adults: less than 85 units/mLSchool-age children: less than 170 units/mLPreschool children: less than 60 units/mLNote: 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 meanIncreased levels of DNase B levels may indicate:Rheumatic feverPost-streptococcal glomerulonephritis after strep throat or strep-related skin infection
What the risks areVeins 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 bleedingFainting or feeling light-headedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)
Special considerationsWhen used together with the ASO titer test, more than 90% of past streptococcal infections can be correctly identified.
ReferencesBisno AL, Stevens DL. Streptococcus pyogenes. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 198.Stevens DL. Streptococcal infections. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 312.