May 1, 2007 Beckman Coulter, Inc. Louisiana Acquisition Sub, Inc.

Exhibit (d)(8)

May 1, 2007

Xxxxxxx Xxxxxxx, Inc.

Louisiana Acquisition Sub, Inc.

0000 X. Xxxxxx Xxxxxxxxx

Fullerton, CA 92834-3100

Attn: Xxxx Xxxxx

Dear Xx. Xxxxx:

I hereby acknowledge that the terms of the Tender and Stockholder Support Agreement, dated March 24, 2007, by and among Xxxxxxx Xxxxxxx, Inc., Louisiana Acquisition Sub, Inc., Xxx X. Xxxxxxxxxxxx and Xxxx Xxxxxxxxxxxx remain in full force and effect and continue to apply to the terms of the Agreement and Plan of Merger dated as of March 24, 2007 by and among Xxxxxxx Xxxxxxx, Inc., Louisiana Acquisition Sub, Inc. and Biosite Incorporated, as amended by the Amendment to the Agreement and Plan of Merger, dated May 1, 2007.

Yours Truly,

/s/    XXX X. XXXXXXXXXXXX        

Xxx X. Xxxxxxxxxxxx