Davis's Lab & Diagnostic Tests

Antideoxyribonuclease-B, Streptococcal

General

Synonym/Acronym:
ADNase-B, AntiDNase-B titer, antistreptococcal DNase-B titer, streptodornase.

Common Use:
To assist in assessing the cause of recent infection, such as streptococcal exposure, by identification of antibodies.

Specimen:
Serum (1 mL) collected in a red-top tube.

Normal Findings:
(Method: Nephelometry)

AgeNormal Results
1–6 yrLess than 70 units/mL
7–17 yrLess than 170 units/mL
18 yr and olderLess than 120 units/mL

Description

The presence of streptococcal deoxyribonuclease (DNase)-B antibodies is an indicator of recent group A, beta hemolytic streptococcal infection, especially if a rise in antibody titer can be shown. This test is more sensitive than the antistreptolysin O (ASO) test. Anti-DNase B titers rise more slowly than ASO titers, peaking 4 to 8 wk after infection. They also decline much more slowly, remaining elevated for several months. A rise in titer of two or more dilution increments between acute and convalescent specimens is clinically significant.

Indications

  • Investigate the presence of streptococcal antibodies as a source of recent infection

Potential Diagnosis

Increased In:

Presence of antibodies, especially a rise in titer, is indicative of exposure.

  • Post streptococcal glomerulonephritis
  • Rheumatic fever
  • Streptococcal infections (systemic)

Decreased In:
N/A

Critical Findings

N/A

Interfering Factors

N/A

Nursing Implications Procedure

Pretest

  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this test can assist in documenting recent streptococcal infection.
  • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s immune system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values).
  • Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • There are no food, fluid, or medication restrictions unless by medical direction.

Intratest

  • If the patient has a history of allergic reaction to latex, avoid the use of equipment containing latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
  • Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
  • Promptly transport the specimen to the laboratory for processing and analysis.

Post Test

  • A report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
  • Administer analgesics and antibiotics if ordered. Remind the patient of the importance of completing the entire course of antibiotic therapy, even if signs and symptoms disappear before completion of therapy.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Inform the patient that a convalescent specimen may be requested in 7 to 10 days. Answer any questions or address any concerns voiced by the patient or family.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs