EX-99.A.5

Exhibit (a)(5)

OFFER TO PURCHASE FOR CASH

ALL OUTSTANDING SHARES OF COMMON STOCK

(Including the Associated Rights to Purchase Shares of Series A Junior

Participating Preferred Stock)

DADE BEHRING HOLDINGS, INC.

$77 Net Per Share in Cash

BELFAST MERGER CO.

a wholly-owned subsidiary of

SIEMENS CORPORATION

an indirect, wholly-owned subsidiary of

SIEMENS AKTIENGESELLSCHAFT

THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON WEDNESDAY, SEPTEMBER 5, 2007, UNLESS THE OFFER IS EXTENDED.

, 2007

To Brokers, Dealers, Commercial Bank, Trust Companies and Other Nominees:

We have been appointed by Belfast Merger Co., a Delaware corporation (“Purchaser”), which is a wholly-owned subsidiary of Siemens Corporation, a Delaware corporation (“Parent”), which is an indirect, wholly-owned subsidiary of Siemens Aktiengesellschaft, a corporation formed under the laws of the Federal Republic of Germany, to act as Dealer Manager in connection with Purchaser’s offer to purchase all outstanding Shares of common stock, par value $0.01 per share (the “Common Stock”), of Dade Behring Holdings, Inc., a Delaware corporation (the “Company”), together with the associated rights to purchase shares of Series A Preferred Junior Participating Stock (the “Rights”) issued pursuant to the Rights Agreement (the “Rights Agreement”), dated as of October 3, 2002, between the Company and Mellon Investor Services LLC, as Rights Agent (the Common Stock and the Rights together being referred to herein as the “Shares”), at $77.00 per Share, net to the seller in cash, upon the terms and subject to the conditions set forth in the Offer to Purchase dated August 8, 2007, and in the related Letter of Transmittal (which, together with any amendments or supplements hereto or thereto, collectively constitute the “Offer”) enclosed herewith. Please furnish copies of the enclosed materials to those of your clients for whose accounts you hold Shares registered in your name or in the name of your nominee.

The Offer is being made in accordance with an Agreement and Plan of Merger (the “Merger Agreement”), dated as of July 25, 2007, by and among Parent, Purchaser and the Company. The Merger Agreement provides for, among other things, the making of the Offer by Purchaser, and further provides that Purchaser will merge with and into the Company (the “Merger”) as soon as practicable following the satisfaction or waiver of each of the conditions to the Merger set forth in the Merger Agreement. Following the Merger, the Company will continue as the surviving corporation, wholly-owned by Parent, and the separate corporate existence of Purchaser will cease.

The Board of Directors of the Company, at a meeting held on July 24, 2007, determined by unanimous vote that the Merger Agreement and the transactions contemplated thereby, including the Offer and the Merger, are advisable, fair to and in the best interests of the Company’s stockholders, and approved and adopted the Merger Agreement and the transactions contemplated thereby. The Board of Directors unanimously recommends that the Company’s stockholders tender their Shares pursuant to the Offer and, if required under Delaware law, vote to adopt the Merger Agreement.

The Offer is conditioned upon, among other things, (i) a number of Shares being validly tendered and not withdrawn on the applicable Expiration Date (as defined in the Offer to Purchase) of the Offer that, together with any Shares beneficially owned by Parent or any of its direct or indirect subsidiaries (including Purchaser), constitute a majority of (a) all outstanding Shares plus, at the election of Parent, (b) Shares issuable upon exercise of options and other similar rights that by their terms are or will become exercisable before six months after the acceptance for purchase by Purchaser of Shares pursuant to the Offer and (ii) the receipt of approvals required by or the expiration or termination of the applicable waiting period under United States antitrust law and the European Merger Control Law. The Offer is also subject to the satisfaction or waiver of certain other conditions. See Sections 1 and 13 of the Offer to Purchase.

For your information and for forwarding to your clients for whom you hold Shares registered in your name or in the name of your nominee, we are enclosing the following documents:

1. Offer to Purchase dated August 8, 2007;

2. Letter of Transmittal for your use in accepting the Offer and tendering Shares and for the information of your clients;

3. Notice of Guaranteed Delivery to be used to accept the Offer if certificates for the Shares and all other required documents cannot be delivered to Mellon Investor Services LLC (the “Depositary”), or if the procedures for book-entry transfer cannot be completed, by the Expiration Date or the expiration of any Subsequent Offering Period (as defined in the Offer to Purchase);

4. A printed form of letter which may be sent to your clients for whose accounts you hold Shares registered in your name or in the name of your nominee, with space provided for obtaining such clients’ instructions with regard to the Offer;

5. A letter to stockholders of the Company from Jim Reid-Anderson, Chief Chairman, President and Executive Officer of the Company, together with a Solicitation/Recommendation Statement on Schedule 14D-9 dated August 8, 2007, which has been filed by the Company with the Securities and Exchange Commission and includes the

recommendation of the Board of Directors of the Company that stockholders accept the Offer and tender their Shares to Purchaser pursuant to the Offer;

6. Guidelines of the Internal Revenue Service for Certification of Taxpayer Identification Number on Substitute Form W-9; and

7. A return envelope addressed to the Depositary.

Upon the terms and subject to the conditions of the Offer (including, if the Offer is extended or amended, the terms and conditions of any such extension or amendment), Purchaser will accept for payment and pay for any Shares which are validly tendered prior to the Expiration Date, or any Subsequent Offering Period, and not theretofore properly withdrawn, when permitted, when, as and if Purchaser gives oral or written notice to the Depositary of Purchaser’s acceptance of such Shares for payment pursuant to the Offer. Payment for any Shares purchased pursuant to the Offer will in all cases be made only after timely receipt by the Depositary of (i) certificates for the Shares, or timely confirmation of a book-entry transfer of such Shares into the Depositary’s account at The Depository Trust Company, pursuant to the procedures described in Section 3 of the Offer to Purchase, (ii) a properly completed and duly executed Letter of Transmittal (or a properly completed and manually signed facsimile thereof) or an Agent’s Message (as defined in the Offer to Purchase) in connection with a book-entry transfer and (iii) all other documents required by the Letter of Transmittal.

Purchaser will not pay any fees or commissions to any broker or dealer or other person (other than the Depositary, the Information Agent and the Dealer Manager as described in the Offer to Purchase) for soliciting tenders of the Shares pursuant to the Offer. Purchaser will, however, upon request, reimburse brokers, dealers, commercial banks and trust companies for customary mailing and handling costs incurred by them in forwarding the enclosed materials to their customers.

Purchaser will pay or cause to be paid all stock transfer taxes applicable to its purchase of the Shares pursuant to the Offer, except as otherwise provided in Instruction 6 of the Letter of Transmittal.

WE URGE YOU TO CONTACT YOUR CLIENTS AS PROMPTLY AS POSSIBLE. PLEASE NOTE THAT THE OFFER AND WITHDRAWAL RIGHTS EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON WEDNESDAY, SEPTEMBER 5, 2007, UNLESS THE OFFER IS EXTENDED.

In order to take advantage of the Offer, (i) a duly executed and properly completed Letter of Transmittal (or a manually signed facsimile thereof), with any required signature guarantees, or an Agent’s Message (as defined in the Offer to Purchase) in connection with a book-entry transfer of the Shares, and any other required documents, should be sent to the Depositary and (ii) certificates representing the tendered Shares should be delivered or tendered by book-entry transfer, all in accordance with the Instructions set forth in the Letter of Transmittal and in the Offer to Purchase.

If holders of the Shares wish to tender, but it is impracticable for them to forward their certificates or other required documents or to complete the procedures for delivery by book-entry transfer prior to the Expiration Date, a tender may be effected by following the guaranteed delivery procedures specified in Section 3 of the Offer to Purchase.

Requests for additional copies of the enclosed materials may be obtained from the Information Agent. Any inquiries you may have with respect to the Offer should be addressed to the Information Agent or the undersigned at the addresses and telephone numbers set forth on the back cover of the Offer to Purchase.

Very truly yours,

J.P. MORGAN SECURITIES INC.

NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU AS AN AGENT OF PURCHASER, PARENT, THE COMPANY, THE DEALER MANAGER, THE INFORMATION AGENT, THE DEPOSITARY, OR ANY AFFILIATE OF ANY OF THE FOREGOING, OR AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR MAKE ANY STATEMENT ON BEHALF OF ANY OF THEM IN CONNECTION WITH THE OFFER OTHER THAN THE DOCUMENTS ENCLOSED HEREWITH AND THE STATEMENTS CONTAINED THEREIN.