Cat. no. U259 Deionized Water with Tween®80, 125ml Polycarbonate Bottle, 100ml 16 bottles/box
Cat. no. V03 Water with Tween® 80, 13x100mm Tube, 3ml 20 tubes/box
Cat. no. V13 Water with Tween® 80, 16x125mm Tube, 13ml 20 tubes/box
Cat. no. V25 Water with Tween® 80, 20x125mm Tube, 24ml 20 tubes/box


The Hardy Diagnostics Water with Tween® 80 products are recommended for the preparation of microbial suspensions.

Product is not intended to be used for the diagnosis of human disease.


Diluent solutions are used for preparing microbial and antimicrobial suspensions when it is necessary to deliver a standardized inoculum of microbes or standard concentration of antimicrobial agents. Delivery of a standard inoculum of microbes and antimicrobials provides consistent test results and allows quantitative analysis of drug potencies and susceptibilities of microbes. Test results are made even more reliable by the addition of Tween® 80 to the diluent. Tween® 80, a wetting agent, is used to reduce the surface tension that develops when using plastic seed trays and plastic pipets. Tween® 80 prevents the dispersion of microbes, thereby allowing the delivery of a consistent inoculum which further assures reliability of test results.


Ingredients per liter of deionized water:*

Cat. no. U259:
Tween® 80 1.0ml

Final pH 7.2 +/- 0.2 at 25 ºC.

Cat. no. V03, V13, and V25:
Tween® 80 0.2ml

Final pH 7.2 +/- 0.3 at 25 ºC.

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


Storage: Upon receipt, store the product at 2-30 ºC. Products should not be used if there are any signs of contamination, deterioration, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.


Product nos. V03, V13, and V25:

Product no. U259:


Specimen Collection: Specimen collection is not applicable since Water with Tween® 80 is not used in the primary isolation of microbes from clinical specimens.

Method of Use: Solutions for inoculation should be prepared by inoculating the diluent with one to five isolated colonies of test organism. The suspension should be adjusted to the concentration of the appropriate McFarland inoculum Standard.

Refer to the Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS) publications "Standards for Antimicrobial Susceptibility Testing" for further details.(1,2)


Water with Tween® 80 lacks nutrient substances, and therefore does not support microbial growth. However, nutrient carry-over may allow growth to continue.


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


Water with Tween® 80 is not a growth medium. It is tested for sterility only.


Water with Tween® 80 should appear clear and colorless.


1. Performance Standards for Antimicrobial Disk Susceptibility Tests, M2-current edition. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Villanova, PA.

2. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically, 2nd ed., M7-current edition. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Villanova, PA.

3. 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.

4. Versalovic, J., et al. Manual of Clinical Microbiology. American Society for Microbiology, Washington, D.C.

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

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

Tween is a registered trademark of ICI Americas, Inc.