Cat. no. C7620 CRITERION™ Modified Casman Agar Base 86gm
Cat. no. C7621 CRITERION™ Modified Casman Agar Base 500gm
Cat. no. C7622 CRITERION™ Modified Casman Agar Base 2kg
Cat. no. C7623 CRITERION™ Modified Casman Agar Base 10kg
Cat. no. C7624 CRITERION™ Modified Casman Agar Base 50kg


Hardy Diagnostics CRITERION™ Modified Casman Agar Base is recommended for the cultivation of fastidious microorganisms, such as Haemophilus spp.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.


In 1947, Casman developed a medium for the cultivation of fastidious microorganisms that did not require the use of fresh meat infusion in the basal medium, but instead utilized beef and yeast extracts and peptones.(1) Beef extract enhances the development of pathogenic cocci.(2,3) Along with peptones, beef extract provides amino acids and other complex nitrogenous nutrients. Yeast extract serves as a source of B-complex vitamins. Dextrose, corn starch and purified agar are also incorporated into the medium. Dextrose enhances the development of pathogenic cocci while corn starch and purified agar allow for the growth of Neisseria gonorrhoeae without interfering with hemolytic reactions.

CRITERION™ Modified Casman Agar Base is a non-selective, peptone-based medium that can be supplemented with blood for the growth of fastidious microorganisms. Blood supplies hemin (X-factor) and nicotinamide adenine dinucleotide (NAD or V-factor), which are growth factors required by Haemophilus influenzae . Rabbit and horse bloods are generally preferred as they are relatively free of the enzyme NADase that destroys V-factor. However, sheep blood has a longer shelf life and is less prone to spontaneous hemolysis and contamination. Therefore, if sheep blood is used, nicotinamide (also known as niacinamide or nicotinic acid amide) should be incorporated into the medium to inhibit the nucleotidase of sheep blood erythrocytes that can destroy the V-factor.(3) CRITERION™ Modified Casman Agar Base formulation contains this ingredient.

CRITERION™ Modified Casman Agar Base can also be supplemented with antibiotics, such as bacitracin, thereby making the medium selective for Haemophilus spp. Modified Casman Agar is also useful in identifying the various species of Haemophilus by pattern of hemolysis. H. influenzae and H. parainfluenzae will grow but will not exhibit beta-hemolysis. H. hemolyticus and H. parahemolyticus will also grow but will not be beta-hemolytic. Bacitracin can be used to inhibit most strains of streptococci, staphylococci, Neisseria and Micrococcus species.


Gram weight per liter: 43.0gm/L
Yeast Etract 5.0gm
Casein Peptone 10.0gm
Meat Peptone 5.0gm
Sodium Chloride 5.0gm
Beef Extract 3.0gm
Corn Starch 1.0gm
Niacinamide 0.5gm
Glucose 0.5gm
Agar 14.0gm

Additional ingredients, if desired: **
Animal blood (horse, rabbit and/or sheep) 50.0ml
Bacitracin 375.0mg

Final pH 7.3 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

** Items sold separately.


Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original beige.

Store the prepared culture media at 2-8ºC.



1. Suspend 43gm of the dehydrated culture media in 1 liter of distilled or deionized water. Stir to mix thoroughly.

2. Heat to boiling for one minute to dissolve completely.

3. Sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC.

5. Aseptically add 50ml of animal blood (horse, rabbit and/or sheep) and 375mg of bacitracin, if desired. Stir while dispensing.

6. Aseptically pour into desired sterile containers.


For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. J82 for Haemophilus identification.



Standard microbiological supplies and equipment such as autoclaves, incinerators, antibiotics, animal blood and incubators, etc., are not provided.


Test Organisms Inoculation Method* Incubation Results***
Time Temperature Atmosphere
Haemophilus parahaemolyticus
ATCC ® 10014
A 24-48hr 35°C CO 2 ** Growth; faint beta-hemolysis at 48hrs
Haemophilus influenzae
ATCC ® 10211
A 24-48hr 35°C CO 2 ** Growth; no hemolysis

** Atmosphere of incubation is enriched with 5-10% CO2.

*** Expected results when prepared with 5% sheep blood.

User Quality Control

Physical Appearance

CRITERION™ Modified Casman Agar Base powder should appear homogeneous, free-flowing, and beige in color. The prepared basal media should appear opaque, and beige in color. The prepared media, after the addition of animal blood, should appear opaque, with no hemolysis, and red in color.


1. Casman. 1947. Am. J. Clin. Pathol.; 17:281.

2. Casman. 1942. J. Bacteriol.; 43:33.

3. Casman. 1947. J. Bacteriol.; 53:561.

4. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

5. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

6. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

7. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

8. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Wayne, PA.

ATCC is a registered trademark of the American Type Culture Collection.