Anti-DNase B Health Article

Definition

Anti-DNase B is a blood test to look for a substance produced by Group A Streptococcus bacteria, which causes strep throat.

See also:

• ASO titer
• Strep throat
• Streptococcal screen

Alternative Names

Antideoxyribonuclease B titer; ADN-B test

How the test is performed

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.

Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

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.

Normal Values

A negative test is normal.

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

What abnormal results mean

Increased levels of DNase B levels may be due to:

• Rheumatic fever
• Post-streptococcal glomerulonephritis after strep throat or strep-related skin infection

What the risks are

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)

Special considerations

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