Cat. no. Z68 Lactophenol Cotton Blue Stain 15ml


Hardy Diagnostics Lactophenol Cotton Blue Stain is recommended for mounting and staining yeast and molds.


Lactophenol Cotton Blue Stain is formulated with lactophenol, which serves as a mounting fluid, and cotton blue. Organisms suspended in the stain are killed due to the presence of phenol. The high concentration of the phenol deactivates lytic cellular enzymes thus the cells do not lyse. Cotton blue is an acid dye that stains the chitin present in the cell walls of fungi.


Ingredients per liter:*

Phenol 200.0gm
Cotton Blue 0.5gm
Glycerol 400.0ml
Lactic Acid 200.0ml
Deionized Water 200.0ml

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


Upon receipt store at 2-30ºC. Product should not be used if there are any signs of contamination, deterioration, or if the expiration date has passed. Product is light sensitive; protect from light.


Warning: This product causes irritation, may cause eye burns and is harmful if inhaled. Avoid contact with skin. Use with adequate ventilation. Wash thoroughly after handling.


Specimen Collection: This product is intended to be used primarily with pure cultures, although certain specimens may be examined directly using this stain. Consult appropriate references for further information concerning the use of Lactophenol Cotton Blue Stain with specimens. (5,7,8)

Method of Use: Place a drop of Lactophenol Cotton Blue Stain in the center of a clean slide. Remove a fragment of the fungus colony 2-3mm from the colony edge using an inoculating or teasing needle or MycoMount™ adhesive strips (Cat. no. MM40). Place the fragment in the drop of stain and tease gently. Apply a coverslip. Do not push down or tap the cover slip as this may dislodge the conidia from the conidiophores. Examine the preparation under low and high, dry magnification for the presence of characteristic mycelia and fruiting structures. Consult appropriate references for diagnostic features of fungi isolated in clinical and non-clinical specimens. (1-6)


Lactophenol Cotton Blue Stain is useful in the recognition and presumptive identification of fungi. Additional characteristics including colony morphology and biochemical tests should be used where appropriate for final identification. For further information, consult the appropriate references.(1-6)


Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


Test Organisms Results
Aspergillus brasiliensis
formerly A. niger
ATCC ® 16404

Delicate blue hyphae and fruiting structures with a pale blue background.
Trichophyton mentagrophytes
ATCC ® 9533
Delicate blue hyphae and fruiting structures with a pale blue background.

User Quality Control

It is recommended that each new lot or shipment of reagent be tested with known positive and negative controls. (3,9)

Physical Appearance

Lactophenol Cotton Blue Stain should appear clear, and blue in color.

Lactophenol Cotton Blue Stain

Lactophenol Cotton Blue Stain (Cat. no. Z68).

Lactophenol Cotton Blue Stain, M. gypseum

Microscopic image of Microsporum gypseum stained with Lactophenol Cotton Blue Stain (Cat. no. Z68).


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

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

3. Centers for Medicare and Medicaid, Appendix C, Survey Procedures and Interpretive Guidelines for Laboratories and Laboratory Services. Subpart K - Quality System for Non-Waived Testing. 493;1200-1265.

4. Cumitech 11: Practical Methods for Culture and Identification of Fungi in the Clinical Microbiology Laboratory. 1980. American Society for Microbiology, Washington, D.C.

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

6. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

7. Larone, D.H. Medically Important Fungi: A Guide to Identification, American Society for Microbiology. Washington, D.C.

8. Kwon-Chung, K.J. and J.E. Bennett. 1992. Medical Mycology. Lea and Febiger, Malvern, PA.

9. Commission on Laboratory Accreditation. 2004. Laboratory Accreditation Program Microbiology Checklist. College of American Pathologists.

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