EXHIBIT F
                                                                       ---------

                            CERTIFICATE OF AMENDMENT
                                       OF
                            ARTICLES OF INCORPORATION
                                       OF
                                  LABONE, INC.
                       ----------------------------------

      Pursuant to the provisions of the General and Business Corporation Law of
Missouri, the undersigned Corporation certifies the following:

      (1)   The name of the corporation is LabOne, Inc. (the "Corporation").

      (2)   The amendment to the Corporation's Articles of Incorporation set
            forth below was adopted by the shareholders of the Corporation on
            [___________] [___], [20__].

      (3)   Article X of the Company's Articles of Incorporation is hereby
            amended by deleting in its entirety Section B(2) and replacing it
            with the following:

            "2. The term "Related Person" shall mean any individual,
            corporation, partnership or other person or entity which, as of the
            record date for the determination of shareholders entitled to notice
            of and to vote on any Business Combination, or immediately prior to
            the consummation of any such Business Combination, is a "Beneficial
            Owner" (as defined in Rule 13d-3 of the General Rules and
            Regulations under the Securities Exchange Act of 1934 as in effect
            at the date of the adoption of this Article X by the shareholders of
            the Corporation) (collectively and as so in effect, the "Exchange
            Act") of shares of any class or series of capital stock of the
            Corporation which, when combined with the shares of such class or
            series of stock of which any "Affiliates" or "Associates" (as
            defined in Rule 12b-2 of the Exchange Act) of such individual,
            corporation, partnership or other person or entity are Beneficial
            Owners, amount to ten percent (10%) or more of the outstanding
            shares of such class or series of stock, and any Affiliate or
            Associate of such Related Person; provided, however, that neither
            Welsh, Carson, Anderson & Stowe IX, L.P. ("WCAS") nor any of its
            general partners or Controlled Entities ("WCAS Parties") shall be
            considered a Related Person. "Controlled Entities" shall mean
            entities in which any one or more of the WCAS Parties owns a
            majority of the voting shares or securities or has the ability
            (whether through the ownership of voting securities, contracts or
            otherwise) to elect a majority of the board of directors or similar
            governing body or of which any one or more of the WCAS Parties has
            the authority to control or direct investment decisions."



      (4)   Article X of the Company's Articles of Incorporation is hereby
            amended by deleting in its entirety Section B(3) and replacing it
            with the following:

            "3. The term "Continuing Directors" shall mean the individuals who
            constituted the Board of Directors of the Corporation on the date of
            this amendment to Article X (the "Incumbent Directors"); provided,
            that any individual becoming a director during any year shall be
            considered to be an Incumbent Director if (i) such individual's
            election, appointment or nomination was recommended or approved by
            at least two-thirds of the other Incumbent Directors continuing in
            office following such election, appointment or nomination present,
            in person or by telephone, at any meeting of the Board of Directors
            of the Corporation, after the giving of a sufficient notice to each
            Incumbent Director so as to provide a reasonable opportunity for
            such Incumbent Directors to be present at such meeting or (ii) such
            individual was nominated, appointed or selected by the holders of
            Series B-1 Preferred Stock or nominated, appointed or selected in
            accordance with Section 6.02 of that certain Securities Purchase
            Agreement dated August 31, 2001 among the Company, WCAS and the
            other purchasers named on Schedule I thereto."

      (5)   On the record date for the shareholders meeting held on
            [_____________] [___], [20__], the Corporation had [____________]
            shares outstanding. All [____________] shares were entitled to vote
            on the amendment.






      IN WITNESS WHEREOF, the President of LabOne, Inc. has executed this
      instrument and the Secretary of LabOne, Inc. has affixed its corporate
      seal hereto and attested said seal on the [____] day of [__________],
      [20__].


                                                  LABONE, INC.


                                                  By:_______________________
                                                  W. T. Grant II
                                                  President


         ATTEST:


         __________________________
         Joseph C. Benage
         Secretary






         STATE OF KANSAS   )
                           ) ss.
         COUNTY OF JOHNSON )

               I, _______________________, a Notary Public do hereby certify
         that on this ____ day of _____________, 20__, personally appeared
         before me ________________, who being by me first sworn, declared that
         he is the President of LabOne, Inc., that he signed the foregoing
         document as President of the corporation, and that the statements
         therein contained are true.


                                                     _________________________
                                                     Notary Public

         My commission expires:


         ______________________