Skip to content

Streptococcal DNAse B Test (Qualitative)

Published: August 9, 2026Updated: August 16, 2026

This test checks whether your sample contains DNA from certain bacteria (Group A Streptococcus). It helps determine if infection is likely and guides treatment decisions.

Quick summary

["A quick way to identify possible Group A strep infection in your body fluids."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
14207-5
Short code
Strep DNAse B Titr Ser
Synonyms
Strep DNAse B Titr Ser
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

The test detects the presence of **DNAse B**, an enzyme produced by some strains of Group A Streptococcus (GAS). If GAS is present, the enzyme breaks down DNA, and the test can identify this activity. This is a qualitative (yes/no) result, not a measurement of exact amounts.

Why It’s Done

Doctors may order this test if you have symptoms like sore throat, fever, or skin infections that could be caused by GAS. It’s often used alongside other tests (like rapid strep swabs) to confirm or rule out infection.

Sample and Method

The test uses a **serum/plasma sample** (liquid from blood) and relies on a **turbidimetric (turb)** method to detect DNA breakdown. No special preparation is needed, but blood should be drawn early in the morning for best accuracy.

What the Results Mean

A **positive result** (DNA breakdown detected) suggests GAS may be present and could require antibiotics. A **negative result** means no DNA breakdown was found, but other infections or conditions may still be possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test helps confirm Group A strep infections quickly, which is critical for treating sore throats, skin infections, or other symptoms. Early treatment with antibiotics can prevent complications like rheumatic fever. However, it’s not a standalone test—results should be interpreted by your healthcare provider alongside symptoms and other tests.

Short name

Strep DNAse B Screen

Frequently asked questions

How long does it take to get results?
Results are typically available within **1–2 business days**, depending on lab processing. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
No special diet is needed, but avoid heavy meals or alcohol before blood drawing. Follow any instructions your doctor or lab provides for best accuracy.
Is this test painful?
The blood draw itself may cause mild discomfort, but the test itself is non-invasive and painless. Most people tolerate it well, and numbing cream can be used if needed.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy