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                     SECURITIES AND EXCHANGE COMMISSION
                           Washington, D.C. 20549

                                SCHEDULE TO
                               (Rule 14d-100)
               Tender Offer Statement Under Section 14(d)(1)
         or Section 13(e)(1) of the Securities Exchange Act of 1934
                             (Amendment No. 3)

                                    and

                                SCHEDULE 13D
                               (Rule 13d-101)

                              (Amendment No. 1)

                                VYSIS, INC.
                     (Name of Subject Company (Issuer))

                         RAINBOW ACQUISITION CORP.
                        a wholly owned subsidiary of
                            ABBOTT LABORATORIES
                    (Names of Filing Persons (Offerors))

                  COMMON STOCK, PAR VALUE $.001 PER SHARE
                       (Title of Class of Securities)

                                928961-10-1
                   (CUSIP Number of Class of Securities)

                              Jose M. de Lasa
            Senior Vice President, Secretary and General Counsel
                            Abbott Laboratories
                            100 Abbott Park Road
                      Abbott Park, Illinois 60064-6400
                               (847) 937-6100
                   (Name, address and telephone number of
                    person authorized to receive notices
              and communications on behalf of filing persons)

                              With a copy to:
                       Charles W. Mulaney, Jr., Esq.
              Skadden, Arps, Slate, Meagher & Flom (Illinois)
                           333 West Wacker Drive
                          Chicago, Illinois 60606
                         Telephone: (312) 407-0700
                         CALCULATION OF FILING FEE

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   Transaction Valuation*                             Amount of Filing Fee
      $375,598,258.50                                      $75,119.66
- ---------------------------------------------------------------------------
*    Estimated for purposes of calculating the filing fee only. The filing
     fee calculation assumes the purchase of 10,291,789 outstanding shares
     of common stock of Vysis, Inc. at a purchase price of $30.50 per
     share. The transaction value also includes the offer price of $30.50
     per share, multiplied by 2,002,908, the estimated number of options
     outstanding under Vysis, Inc's employee stock option plans which are
     or will be, as a result of the transaction, exercisable for shares of
     common stock of Vysis, Inc. The amount of the filing fee calculated in
     accordance with Rule 0-11 of the Securities Exchange Act of 1934, as
     amended, equals 1/50 of 1% of the transaction value.

[X]  Check the box if any part of the fee is offset as provided by Rule
     0-11(a)(2) and identify the filing with which the offsetting fee was
     previously paid. Identify the previous filing by registration
     statement number or the Form or Schedule and the date of its filing.

Amount Previously Paid: $75,119.66 Filing party: Abbott Laboratories and Rainbow Acquisition Corp. Form or Registration No.: Schedule TO Date Filed: October 31, 2001
[_] Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer. Check the appropriate boxes below to designate any transactions to which the statement relates: [X] third-party tender offer subject to Rule 14d-1. [_] issuer tender offer subject to Rule 13e-4. [_] going-private transaction subject to Rule 13e-3. [X] amendment to Schedule 13D under Rule 13d-2. Check the following box if the filing is a final amendment reporting the results of the tender offer: [X] =========================================================================== - --------------------- CUSIP No. 928961-10-1 - --------------------- - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) ABBOTT LABORATORIES (I.R.S. IDENTIFICATION NO. 36-0698440) - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |_| (b) |_| - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS OO - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS |_| REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION ILLINOIS - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY --------------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 10,192,813 REPORTING --------------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- --------------------------------------------------------- 10 SHARED DISPOSITIVE POWER 10,192,813 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 10,192,813 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES EXCLUDES CERTAIN ISSUES |_| - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 98.6% - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON CO - --------------------------------------------------------------------------- - -------------------------------------------- ------------------------------- CUSIP No. 928961-10-1 - -------------------------------------------- ------------------------------- xxx - --------------------------------------------------------------------------- 1 NAME OF REPORTING PERSON I.R.S. IDENTIFICATION NO. OF ABOVE PERSON (ENTITIES ONLY) RAINBOW ACQUISITION CORP. - --------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |_| (b) |_| - --------------------------------------------------------------------------- 3 SEC USE ONLY - --------------------------------------------------------------------------- 4 SOURCE OF FUNDS OO - --------------------------------------------------------------------------- 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS |_| REQUIRED PURSUANT TO ITEM 2(d) OR 2(e) - --------------------------------------------------------------------------- 6 CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE - --------------------------------------------------------------------------- NUMBER OF 7 SOLE VOTING POWER SHARES -0- BENEFICIALLY --------------------------------------------------------- OWNED BY 8 SHARED VOTING POWER EACH 10,192,813 REPORTING --------------------------------------------------------- PERSON 9 SOLE DISPOSITIVE POWER WITH -0- --------------------------------------------------------- 10 SHARED DISPOSITIVE POWER 10,192,813 - --------------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 10,192,813 - --------------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES EXCLUDES CERTAIN ISSUES |_| - --------------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 98.6% - --------------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON CO - --------------------------------------------------------------------------- This Amendment No. 3 (the "Amendment") amends and supplements the Tender Offer Statement on Schedule TO filed with the Securities and Exchange Commission (the "Commission") on October 31, 2001, as amended (the "Schedule TO") by Rainbow Acquisition Corp., a Delaware corporation (the "Purchaser") and a wholly owned subsidiary of Abbott Laboratories, an Illinois corporation ("Abbott") and the Schedule 13D filed with the Commission by Purchaser and Abbott on November 1, 2001. The Schedule TO relates to the offer by the Purchaser to purchase all outstanding shares of common stock, par value $.001 per share (the "Shares"), of Vysis, Inc., a Delaware corporation (the "Company"), at $30.50 per Share net to the seller in cash, upon the terms and conditions set forth in its Offer to Purchase dated October 31, 2001 (the "Offer to Purchase") and in the related Letter of Transmittal (which, together with the Offer to Purchase and any amendments or supplements thereto, collectively constitute the "Offer"). Capitalized terms used and not otherwise defined herein shall have the meanings assigned to such terms in the Offer to Purchase or in the Schedule TO. Items 4, 8 and 11. Items 4, 8 and 11 are hereby amended and supplemented to include the following: The Offer expired at 12:00 midnight, New York City time, on November 29, 2001, and was not extended. Based on information provided by EquiServe Trust Company, N.A., the depositary for the Offer (the "Depositary"), 10,192,813 Shares (including 346,500 Shares subject to guarantee of delivery), representing approximately 98.6% of the outstanding Shares, were validly tendered pursuant to the Offer. Purchaser has accepted for payment all Shares validly tendered and not withdrawn prior to the expiration of the Offer. Pursuant to the terms of the Agreement and Plan of Merger, dated as of October 24, 2001, among Abbott, Purchaser and the Company, Abbott intends to cause the merger of Purchaser with and into the Company (the "Merger") following the expiration of the Offer. Upon consummation of the Merger, each Share issued and outstanding immediately prior to the effective time of the Merger (other than Shares owned by Abbott or any of its subsidiaries or held by the Company as treasury stock or owned by any subsidiaries of the Company, all of which will be cancelled and retired and will cease to exist, and other than Shares that are held by stockholders, if any, who properly exercise their dissenters' rights in accordance with Delaware law) will be cancelled and converted automatically into the right to receive $30.50, without interest thereon, payable to the holder of such Share. On November 30, 2001, Abbott issued a press release announcing the results of the Offer. The full text of press release is filed as Exhibit (a)(5)(E) and is incorporated by reference herein. Item 11. Additional Information. Sections (a)(2) and (a)(3) of Item 11 are hereby amended and supplemented to include the following: On November 29, 2001, the German Federal Cartel Office approved the proposed acquisition of the Company by Abbott. Item 12. Exhibits. (a)(1)(A)* Offer to Purchase dated October 31, 2001. (a)(1)(B)* Letter of Transmittal. (a)(1)(C)* Notice of Guaranteed Delivery. (a)(1)(D)* Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees. (a)(1)(E)* Letter to Clients for use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees. (a)(1)(F)* Guidelines for Certification of Taxpayer Identification Number (TIN) on Substitute Form W-9. (a)(5)(A)* Press Release issued by Abbott on October 24, 2001, incorporated herein by reference to the Schedule TO filed by Abbott on October 24, 2001. (a)(5)(B)* Summary Advertisement as published in The Wall Street Journal on October 31, 2001. (a)(5)(C)* Press Release issued by Abbott on October 31, 2001. (a)(5)(D)* Press Release issued by Abbott on November 23, 2001. (a)(5)(E) Press Release issued by Abbott on November 30, 2001. (b) Not applicable. (d)(1)* Agreement and Plan of Merger, dated as of October 24, 2001, by and among Abbott, the Purchaser, and Vysis. (d)(2)* Stockholder Agreement, dated as of October 24, 2001, by and among Abbott, the Purchaser, Amoco Technology Company and BP America Inc. (d)(3)* Confidentiality Agreement, dated April 17, 2001, as amended on August 21, 2001, between Vysis and Abbott. (d)(4)* Confidentiality Agreement, dated August 21, 2001, between BP Corporation North America Inc. and Abbott. (g) Not applicable. (h) Not applicable. - --------------- * Previously filed. SIGNATURE After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. ABBOTT LABORATORIES By: /s/ RICHARD A. GONZALEZ --------------------------------------- Name: Richard A. Gonzalez Title: Executive Vice President, Medical Products RAINBOW ACQUISITION CORP. By: /s/ THOMAS C. FREYMAN --------------------------------------- Name: Thomas C. Freyman Title: Vice President Dated: November 30, 2001 EXHIBIT INDEX Exhibit No. Exhibit Name ----------- ------------ (a)(1)(A)* Offer to Purchase dated October 31, 2001. (a)(1)(B)* Letter of Transmittal. (a)(1)(C)* Notice of Guaranteed Delivery. (a)(1)(D)* Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees. (a)(1)(E)* Letter to Clients for use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees. (a)(1)(F)* Guidelines for Certification of Taxpayer Identification Number (TIN) on Substitute Form W-9. (a)(5)(A)* Press Release issued by Abbott on October 24, 2001, incorporated herein by reference to the Schedule TO filed by Abbott on October 24, 2001. (a)(5)(B)* Summary Advertisement as published in The Wall Street Journal on October 31, 2001. (a)(5)(C)* Press Release issued by Abbott on October 31, 2001. (a)(5)(D)* Press Release issued by Abbott on November 23, 2001. (a)(5)(E) Press Release issued by Abbott on November 30, 2001. (b) Not applicable. (d)(1)* Agreement and Plan of Merger, dated as of October 24, 2001, by and among Abbott, the Purchaser and Vysis. (d)(2)* Stockholder Agreement, dated as of October 24, 2001, by and among Abbott, the Purchaser, Amoco Technology Company and BP America Inc. (d)(3)* Confidentiality Agreement, dated April 17, 2001, as amended on August 21, 2001, between Vysis and Abbott. (d)(4)* Confidentiality Agreement, dated August 21, 2001, between BP Corporation North America Inc. and Abbott. (g) Not applicable. (h) Not applicable. - --------------- * Previously filed.
                                                          Exhibit (a)(5)(E)

For Immediate Release
- ---------------------
                                                   Media:
                                                   Kathleen O'Neil
                                                   (847) 938-3895

                                                   Financial Community:
                                                   John Thomas
                                                   (847) 938-2655


            ABBOTT LABORATORIES ACQUIRES CONTROL OF VYSIS, INC.
            ---------------------------------------------------

            ABBOTT PARK, Ill., November 30, 2001-- Abbott Laboratories
(NYSE: ABT) announced today that it has acquired control of Vysis, Inc.
(Nasdaq: VYSI).  Abbott's cash tender offer to purchase all of the
outstanding common stock of Vysis expired, as scheduled, at midnight, New
York City time, on Thursday, November 29, 2001. The offer has not been
extended.

            A total of 10,192,813 shares of Vysis common stock were validly
tendered and not withdrawn prior to the expiration of the offer, including
346,500 shares subject to guaranteed delivery procedures. Abbott has
accepted all of these shares for payment. These shares represent
approximately 98.6 percent of Vysis's outstanding shares.

            As the final step of the acquisition process, Abbott intends to
consummate a merger in which remaining Vysis shareholders will receive the
same $30.50 cash price per share as paid in the tender offer.

            Abbott Laboratories is a global, diversified health care
company devoted to the discovery, development, manufacture and marketing of
pharmaceuticals, nutritionals, and medical products, including devices and
diagnostics. The company employs approximately 70,000 people and markets
its products in more than 130 countries. In 2000, the company's sales and
net earnings were $13.7 billion and $2.8 billion, respectively, with
diluted earnings per share of $1.78.

            Abbott's news releases and other information are available on
the company's Web site at www.abbott.com.

            Vysis is a genomic disease management company that develops,
commercializes and markets DNA-based clinical products providing
information critical to the evaluation and management of cancer, prenatal
disorders and other genetic diseases. The company has direct sales
operations in the United States and Europe; a marketing partnership in
Japan with Fujisawa Pharmaceutical Co.; and a worldwide distribution
network. Vysis' news releases and other information are available on the
company's Web site at www.vysis.com.