SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 8-A/A

               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                   PURSUANT TO SECTION 12(b) OR 12(g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934


                                  LABONE, INC.
            (Exact name of registrant as specified in its charter)


             Missouri                          43-1039532
     (State of Incorporation)        (I.R.S. Employer Identification Number)

         10101 Renner Boulevard
             Lenexa, Kansas                                  66219
  (Address of principal executive offices)                (Zip Code)

       Securities to be registered pursuant to Section 12(b) of the Act:

Title Of Each Class                  Name Of Each Exchange On Which
To Be So Registered                  Each Class Is To Be Registered
- -------------------                  ------------------------------
       None                                       None


      If this form relates to the registration of a class of securities pursuant
to  Section  12(b) of the  Exchange  Act and is  effective  pursuant  to General
Instruction A.(c), check the following box.
      [ ]

      If this form relates to the registration of a class of securities pursuant
to  Section  12(g) of the  Exchange  Act and is  effective  pursuant  to General
Instruction A.(d), check the following box. |X|

      Securities  Act  registration  statement  file  number to which this form
relates: _____________ (if applicable)

       Securities to be registered pursuant to Section 12(g) of the Act:

                         Preferred Stock Purchase Rights
                                (Title of class)







                INFORMATION REQUIRED IN REGISTRATION STATEMENT

Item 1.         Description of Registrant's Securities to be Registered

           Item 1 of the Registration  Statement is hereby amended by adding the
following paragraph at the end of Item 1 of the Registration Statement:

           "LabOne,  Inc. (the "Company") is a party to an Agreement and Plan of
Merger (the "Merger Agreement"),  dated as of August 8, 2005, by and among Quest
Diagnostics  Incorporated,  a Delaware corporation ("Quest"),  Fountain, Inc., a
Missouri  corporation and  wholly-owned  subsidiary of Quest ("Merger Sub"), and
the Company.  The Merger Agreement provides,  among other things, for the merger
of Merger Sub with and into the Company (the  "Merger")  subject to  shareholder
and regulatory approval and other terms and conditions.  In contemplation of the
Merger,  the Company and American  Stock Transfer and Trust Company (the "Rights
Agent")  entered  into  the  Amendment  No.  3  to  the  Rights  Agreement  (the
"Amendment"),  dated as of August 8, 2005, amending the Rights Agreement,  dated
as of February 11, 2000, as amended by Amendment No. 1 to the Rights  Agreement,
dated as of August 31, 2001, and Amendment No. 2 to the Rights Agreement,  dated
as of April 20, 2005 (the "Rights  Agreement"),  in order to provide  that:  (a)
none of  Quest  and its  Affiliates  and  Associates  shall be  deemed  to be an
Acquiring Person by virtue of the approval,  execution,  delivery or performance
of the  Merger  Agreement,  or  the  consummation  of  any  of the  transactions
contemplated by the Merger Agreement, (b) no Section 11(a)(ii) Event, Section 13
Event, Distribution Date, Stock Acquisition Date or Triggering Event shall occur
by virtue of the  approval,  execution,  delivery or  performance  of the Merger
Agreement,  or the consummation of any of the  transactions  contemplated by the
Merger Agreement,  and (c) the Agreement and the Rights established thereby will
terminate in all respects immediately prior to the Effective Time (as defined in
the Merger Agreement)."

           A form of the  Amendment  is  attached  hereto as Exhibit  4.4 and is
incorporated  herein by reference.  The foregoing  description  of the Amendment
does not purport to be complete and is qualified in its entirety by reference to
the Amendment.

Item 2.    Exhibits.

           4.1. Rights Agreement dated as of February 11, 2000,  between LabOne,
               Inc. and American Stock Transfer & Trust Company,  which includes
               as Exhibit A, the  Certificate of  Designations  Preferences  and
               Rights of Series A  Preferred  Stock,  as  Exhibit B, the Form of
               Rights  Certificate,  and as Exhibit C, the  Summary of Rights to
               Purchase Preferred Stock  (incorporated by reference from Exhibit
               4.1 to the Company's  Current  Report on Form 8-K filed  February
               14, 2000)

           4.2 Amendment No. 1 to Rights Agreement, dated as of August 31, 2001,
               between  LabOne,  Inc.  and  American  Stock  Transfer  and Trust
               Company,  as Rights Agent (incorporated by reference from Exhibit
               4.6 to the Company's  Current Report on Form 8-K filed October 5,
               2001).


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           4.3 Amendment  No. 2 to  Rights  Agreement,  dated  as of April  20,
               2005,  between  LabOne,  Inc.  and American  Stock  Transfer and
               Trust Company,  as Rights Agent  (incorporated by reference from
               Exhibit 4.1 to the  Company's  Current  Report on Form 8-K filed
               April 25, 2005).

           4.4 Amendment  No. 3 to  Rights  Agreement,  dated as of  August  8,
               2005,  between  LabOne,  Inc.  and American  Stock  Transfer and
               Trust Company,  as Rights Agent  (incorporated by reference from
               Exhibit 4.1 to the  Company's  Current  Report on Form 8-K filed
               August 8, 2005).



                                    SIGNATURE

      Pursuant to the requirements of Section 12 of the Securities  Exchange Act
of 1934, the registrant has duly caused this registration statement to be signed
on its behalf by the undersigned, thereto duly authorized.

                                      LABONE, INC.


Dated: August 8, 2005                 /s/ John W. McCarty
                                      -----------------------------
                                      John W. McCarty
                                      Chief Financial Officer




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