Product number: NCM0161

DNase Agar is used for the differentiation of microorganisms on the basis of deoxyribonuclease activity and is not intended for use in the diagnosis of disease or other conditions in humans.

In 1956, Weckman and Catlin showed a correlation between increased DNase activity of Staphylococcus aureus and positive coagulase activity. Their research suggested DNase activity could be used to identify potentially pathogenic staphylococci. DiSalvo confirmed their results by obtaining excellent correlation between coagulase and DNase activity of staphylococci isolated from clinical specimens. Jeffries, Holtman, and Guse incorporated DNA in agar to study DNase production by bacteria and fungi. Polymerized DNA precipitates in the presence of 1N HCl, creating an opaque medium. Organisms that degrade DNA produce a clear zone around an inoculum streak. Fusillo and Weiss studied calcium requirements of staphylococci for DNase production, and concluded additional calcium was unnecessary when a complete nutritive medium was used.


Formula Liter
Enzymatic Digest of Casein 15.0 g/L
Enzymatic Digest of Animal Tissue 5.0 g/L
Sodium Chloride 5.0 g/L
Deoxyribonucleic Acid 2.0 g/L
Agar 15.0 g/L

Final pH: 7.3 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Inoculate plates by spotting or streaking a heavy inoculum of test organism.
  2. Use a spot approximately 5 mm in diameter or a 1 – 2 cm streak approximately 5 mm wide.
  3. Incubate plates at 35 ± 2°C for 18 – 24 hours and up to 48 hours.
  4. Flood plates with 1 N HCl.
  5. Observe for clearing around the spot or streak. Record results.

Product was previously known as Acumedia Product: 7129 DNase Agar; and LabM Product: LAB095 DNase Agar

Order Details

Product # Product Description
NCM0161A DNase Agar, 500 g
NCM0161B DNase Agar, 5 kg
NCM0161C DNase Agar, 10 kg
NCM0161D DNase Agar, 25 kg (European only size)
NCM0161E DNase Agar, 50 kg (US only size)

Reference Material

NCM0161 - DNase Test Agar, Technical Specifications Sheet [US English]
7129 - DNase Test Agar, Product Information Sheet [English] [Portuguese]
7129 - DNase Test Agar, Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]

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