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Streptococcal D-Nase (Deoxyribonuclease) Activity in Serum

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

This test measures the activity of Streptococcus bacteria’s enzyme, deoxyribonuclease (DNase), in your blood serum. It helps assess whether certain types of group A Streptococcus (GAS) are present in your system.

Quick summary

["This test supports diagnosis of infections caused by specific bacteria and guides treatment decisions."]

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

Key facts at a glance

LOINC
58713-9
Short code
Strep DNAse B+ ASO Ab pnl Ser
Synonyms
Strep DNAse B+ ASO Ab pnl 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, an enzyme produced by some strains of group A Streptococcus bacteria. When these bacteria invade your body, they release DNase into your bloodstream. This enzyme breaks down DNA, and its activity can be measured to identify infection.

Why It Matters in Diagnosis

DNase activity is particularly useful for diagnosing infections caused by certain GAS strains, such as those linked to rheumatic fever or post-streptococcal glomerulonephritis. It helps clinicians confirm the presence of these bacteria before starting appropriate antibiotics.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in your arm. The serum portion (liquid part after blood clots) is tested for DNase activity. This test is usually performed on fresh or refrigerated serum within a few hours of collection.

When This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms suggestive of a bacterial throat or skin infection, such as sore throat, fever, or skin rashes. It may also be used in cases where other tests are inconclusive or to monitor treatment response.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Strep DNase Test

Frequently asked questions

Why was this test ordered?
Your doctor may have ordered this test to check for infections caused by specific types of group A Streptococcus bacteria. Positive results can help confirm the diagnosis and guide treatment decisions, such as antibiotic selection.
What do my results mean?
Results are interpreted by your healthcare provider based on clinical context. Elevated DNase activity may indicate an active infection, while normal levels suggest no infection or absence of the specific bacteria causing concern. Always discuss results with your doctor.
Can I eat or drink before this test?
You may eat and drink normally before this test, as it involves a simple blood draw. However, follow any specific instructions your healthcare provider gives you, such as fasting if required for other tests.
  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