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                                                                    EXHIBIT 10.8

                         AMENDMENT TO THE UROCOR, INC.

                       1997 EMPLOYEE STOCK PURCHASE PLAN

THIS AGREEMENT, by UroCor, Inc. (the "Company"),

                                   WITNESSETH

         WHEREAS, the Company maintains the UroCor, Inc. 1997 Employee Stock
Purchase Plan (the "Plan");

         WHEREAS, the Company has reserved the right to amend the Plan from time
to time; and

         WHEREAS, the Company desires to amend the Plan in connection with the
instrument entitled "Agreement and Plan of Merger among Dianon Systems, Inc.,
UroCor Acquisition Corp. and UroCor, Inc.";

         NOW THEREFORE, the Company hereby agrees to amend the Plan, to provide
as follows:

         1. Section 4.4 of the Plan is hereby amended and restated to provide as
follows:

                    4.4 RIGHT TO DECREASE OR STOP PAYROLL DEDUCTIONS. A
               Participant shall have the right, at any time, to reduce, but not
               below one percent, or discontinue payroll deductions by filing an
               amended payroll deduction form with the Company.

         2. A new Section 6.4 is hereby added to the Plan to provide as follows:

                    6.4 EXPIRATION OF OFFERING PERIOD. Notwithstanding any other
               provision of the Plan to the contrary, as of the "Effective Time"
               defined in the instrument entitled "Agreement and Plan of Merger
               among Dianon Systems, Inc., UroCor Acquisition Corp. and UroCor,
               Inc." (the "Effective Time"), the Offering Period during which
               the Effective Time occurs shall expire. No shares of Stock may be
               purchased in accordance with the provisions of the Plan with
               respect to the expired Offering Period. The Company shall, at the
               Effective Time, pay to each Participant an amount in cash equal
               to the aggregate amount of the funds accumulated by such
               Participant through payroll deductions made during the expired
               Offering Period through the Effective Time.

         3. Section 8.1 of the Plan is hereby amended and restated to provide as
follows:

                    8.1 TERMINATION. The Company may, by action of the Board of
               Directors, terminate the Plan at any time and for any reason. The
               Plan shall automatically terminate upon the purchase by
               Participants of all shares of Stock committed to the Plan, unless
               the number of Shares committed to the Plan are increased by the
               Board of Directors and approved by the shareholders of the
               Company. In addition, the Plan shall automatically terminate as
               of the Effective Time. Upon termination of the Plan, as soon as
               administratively feasible there shall be refunded to each
               Participant the remaining funds in his payroll deduction account,
               and there shall be forwarded to the Participants certificates for
               all shares of Stock held under the Plan for the account of
               Participants.


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         4. Section 8.2 of the Plan is hereby amended and restated to provide as
follows:

                    8.2 AMENDMENT. The Board of Directors reserves the right to
               modify, alter or amend the Plan at any time and from time to time
               to any extent that it deems advisable, including, without
               limiting the generality of the foregoing, any amendment deemed
               necessary to ensure compliance of the Plan with section 423 of
               the Code. The Board of Directors may suspend operation of the
               Plan for any period as it may deem advisable. Any amendment
               changing the aggregate number of Shares to be committed to the
               Plan or the class of Employees eligible to receive Options under
               the Plan must have stockholder approval as set forth in Section
               1.4.

                    Dated:  June 27, 2001