Exhibit 10.19

THIS WARRANT AND THE SHARES OF COMMON STOCK PURCHASABLE  HEREUNDER HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES
LAWS AND  CANNOT  BE  OFFERED,  SOLD,  HYPOTHECATED,  TRANSFERRED  OR  OTHERWISE
DISPOSED OF IN THE ABSENCE OF REGISTRATION  OR THE  AVAILABILITY OF AN EXEMPTION
FROM REGISTRATION UNDER SUCH LAWS AS PROVIDED IN THIS WARRANT

No. of Shares:  500,000                                      Warrant No. _____
Original Issue Date:  May 14, 1999


                                     WARRANT
                      To Purchase Shares of Common Stock of
                                  LABONE, INC.


                  This certifies that, for value received,  HealthPlan Services,
Inc.  ("HealthPlan")  is entitled  to purchase  from  LABONE,  INC.,  a Delaware
corporation,  from time to time prior to the Expiration  Date in accordance with
the terms and  conditions  hereof,  up to 500,000  shares of Common Stock of the
Company at a Purchase  Price per share set forth below.  The number of shares of
Common Stock  purchasable  hereunder and the Purchase Price therefor are subject
to adjustment as hereinafter set forth in Section 6.


         1.       Certain Definitions.  For all  purposes of  this  Warrant  the
following terms shall have the meanings indicated:

                  (a)  "Agreement"  shall mean the Agreement dated April 1, 1999
between the Company and HealthPlan.

                  (b)  "Common   Stock"  shall  mean  the  Company's   presently
authorized  shares of Common  Stock,  par value  $.01 per  share,  and any other
securities  into  which or for  which  the  Common  Stock  may be  converted  or
exchanged pursuant to a plan of recapitalization,  reorganization,  merger, sale
of assets or otherwise.

                  (c)  "Commencement  Date" shall mean the first  anniversary of
the date hereof.




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                  (d) "Company" shall mean LABONE, INC., a Delaware corporation,
and any  company  that shall  succeed  to, or assume,  the  obligations  of said
corporation hereunder.

                  (e)  "Expiration  Date" shall mean 12:01 o'clock a.m.  Central
Time on July 13, 2005,  which is twenty (20)  calendar  quarters plus sixty (60)
days after the Commencement Date.

                  (f) "Lab Revenues"  shall mean all gross revenues  received by
the  Company  during the  applicable  calendar  quarter  from  Payors  under the
Agreement from and after the Commencement Date, whether or not the Agreement has
been  terminated,  provided  that the term  "Lab  Revenues"  shall  not  include
revenues  received by the Company  after (i) a  termination  of the Agreement by
HealthPlan  without  cause  under  Section  8.A  of  the  Agreement  or  (ii)  a
termination  of the  Agreement by the Company for cause under Section 8.B of the
Agreement.

                  (g) "Purchase  Price" or "Purchase Price per share" shall mean
the  purchase  price per  Warrant  Share (as defined  below),  which shall equal
$12.375,  being the  closing  sale  price or, if no sales  were  reported,  then
average of the closing bid and asked prices of the Common Stock,  as reported by
the NASDAQ Stock Market,  on the last  business day prior to the Original  Issue
Date of this Warrant,  as set forth above, as such purchase price may thereafter
be adjusted  from time to time  pursuant to the  provisions  of Section 6 hereof
(rounded to the nearest whole cent).

                  (h)   "Warrantholder"   or  "Registered   Holder"  shall  mean
HealthPlan, or its registered transferee.

                  (i) "Warrant"  shall mean this Warrant and all Warrants issued
in exchange therefor or replacement thereof.

                  (j)  "Warrant  Shares"  shall mean the shares of Common  Stock
purchasable by the Registered  Holder upon the exercise of this Warrant pursuant
to Section 2 hereof, as adjusted from time to time pursuant to Section 6 hereof.

         All terms used in this Warrant  which are not defined in Section 1 have
the meanings respectively set forth therefor elsewhere in this Warrant.





                                      2


         2.       Exercise of Warrant.

                  (a) Subject to the terms and conditions hereof, from and after
the  Commencement  Date and prior to the  Expiration  Date,  this Warrant may be
exercised in whole or in part in respect of vested shares.    Shares  of  Common
Stock shall become vested under this Warrant as follows:

                           (i) for each calendar  quarter  commencing  after the
         Commencement Date in which the Lab Revenues reach $500,000 and are less
         than  $1,000,000,  this Warrant will vest in respect of 5,000 shares of
         Common Stock subject to this Warrant;

                           (ii) for each calendar  quarter  commencing after the
         Commencement  Date in which the Lab Revenues  reach  $1,000,000 and are
         less than  $1,500,000,  this  Warrant  will vest in  respect  of 10,000
         shares of Common Stock subject to this Warrant;

                           (iii)for each calendar  quarter  commencing after the
         Commencement  Date in which the Lab Revenues  reach  $1,500,000 and are
         less than  $2,000,000,  this  Warrant  will vest in  respect  of 15,000
         shares of Common Stock subject to this Warrant;

                           (iv) for each calendar  quarter  commencing after the
         Commencement  Date in which the Lab Revenues  reach  $2,000,000 and are
         less than  $2,500,000,  this  Warrant  will vest in  respect  of 20,000
         shares of Common Stock subject to this Warrant; and

                           (v) for each calendar  quarter  commencing  after the
         Commencement  Date in which the Lab  Revenues  reach  $2,500,000,  this
         Warrant will vest in respect of 25,000  shares of Common Stock  subject
         to this Warrant.

The number of shares vested for an applicable  calendar quarter shall be limited
to the  number of  shares in the  highest  category  set forth in  2(a)(i) - (v)
above,  if any,  which is satisfied  for such  calendar  quarter.  The number of
shares vested for each applicable  calendar quarter, if any, shall be cumulative
with shares  vested from all other  applicable  calendar  quarters.  Once shares
become vested under this Warrant,  they shall remain vested until the Expiration
Date. Anything in this Warrant to the contrary notwithstanding, this Warrant may
not be exercised





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at any time after a material  breach by  HealthPlan of the  Agreement,  provided
that HealthPlan receives notice of such breach,  unless and until such breach is
cured under the applicable  provisions,  if any, of such Agreement  prior to the
Expiration Date. Anything in this Warrant to the contrary notwithstanding,  this
Warrant  may  not be  exercised  in  whole  or in  part at any  time  after  the
Expiration Date.

                  (b) In order to exercise this Warrant in whole or in part, the
Registered  Holder shall complete the "Notice of Intention to Exercise  Warrant"
attached  hereto (the "Notice  Form"),  and deliver this Warrant,  the completed
Notice  Form and either  cash,  a  cashier's  check  payable to the order of the
Company or a wire  transfer  of funds in an amount  equal to the then  aggregate
Purchase Price of the Warrant Shares being purchased, to the Corporate Secretary
of the Company at the  Company's  office  located at 10101 Renner Road,  Lenexa,
Kansas  66219 (or such other  office or agency of the Company as the Company may
designate by notice in writing to the  Registered  Holder).  In no event may the
Warrantholder  exercise the Warrant with respect to more than 500,000  shares of
Common  Stock in the  aggregate,  subject  to  adjustment  as  provided  in this
Warrant.

         3.  Delivery  of Stock  Certificate,  Etc.  Upon  Exercise.  As soon as
practicable after exercise of this Warrant, the Company shall cause to be issued
and  delivered  to the  Registered  Holder  (a) a  certificate  or  certificates
representing  the aggregate  number of shares of Common Stock  specified in said
Notice Form, all of which shares shall be duly  authorized  and validly  issued,
fully paid and  nonassessable,  (b) cash in lieu of any  fractional  share based
upon the fair market  value of a share of Common  Stock,  as  determined  by the
Company and (c) any other securities or property  (including cash) to which such
Registered  Holder is entitled upon such exercise  pursuant to the terms of this
Warrant.  Each stock certificate  representing  shares of Common Stock so issued
and  delivered  shall be  registered  in the name of the  Registered  Holder or,
subject to the  provisions of Sections 4 and 5 hereof,  such other name as shall
be designated by the Registered  Holder.  Such certificate or certificates shall
be deemed to have  been  issued  and the  Warrantholder  or any other  person so
designated to be named therein shall be deemed to have become a holder of record
of such shares of Common Stock only as of the date the certificate  representing
such shares is issued by the Company.






                                       4


         4.       Ownership and Transfer of Warrant and Warrant Shares.

                  (a)  Registered  Holder.  The  Company  may deem and treat the
Registered   Holder  of  this   Warrant   as  the   holder   and  owner   hereof
(notwithstanding  any  notations of  ownership or writing  hereon made by anyone
other than the  Company)  for all  purposes,  notwithstanding  any notice to the
contrary,  until  presentation  of this Warrant for  registration of transfer as
provided in this Section 4.

                  (b) No Transfer. This Warrant may not be sold, transferred, or
assigned by the Registered Holder in whole or in part at any time.

         5.       Compliance with Securities Laws.

                  (a) Accredited  Investor.  By acceptance of this Warrant,  the
Registered  Holder  represents and warrants that it is an "accredited  investor"
within the meaning of Rule  501(a)(3)  of  Regulation  D  promulgated  under the
Securities Act of 1933, as amended (the "Securities Act"), the Registered Holder
being a corporation with total assets in excess of $5,000,000 not formed for the
specific purpose of acquiring the Warrant or the Warrant Shares.

                  (b)  Investment  Intent.  By acceptance  of this Warrant,  the
Registered  Holder represents and warrants that it is acquiring this Warrant and
any Warrant Shares for its own account and for the purpose of investment and not
with  a view  to  the  sale  or  distribution  thereof.  The  Registered  Holder
understands  that this  Warrant and the  Warrant  Shares that may be issued upon
exercise of this Warrant will not have been registered  under the Securities Act
of 1933, as amended (the  "Securities  Act") or any state  securities  laws (the
Company  being under no obligation  to effect such  registration)  and that this
Warrant and the Warrant  Shares must be held  indefinitely  unless a  subsequent
disposition  thereof is registered under the Securities Act and applicable state
securities laws or is exempt from registration as provided herein.

                  (c) Limitation on Transfer. By acceptance of this Warrant, the
Registered  Holder  represents,  covenants,  and agrees that it will not sell or
otherwise dispose of this Warrant or of the Warrant Shares in the absence of (i)
registration  under the Securities Act and applicable  state  securities laws or
(ii) an opinion  acceptable  in form and  substance  to the Company from counsel
reasonably satisfactory to the Company, or an opinion of





                                       5


counsel  to  the  Company,  to the effect that  no registration  is required for
such disposition.

                  (d)  Restrictive  Legend.  Each Warrant shall bear on the face
thereof a legend  substantially in the form of the notice set forth on the first
page of this Warrant.  Upon exercise of any part of the Warrant and the issuance
of any Warrant  Shares,  the Company shall  instruct its transfer agent to enter
stop transfer orders with respect to such Warrant Shares,  and the  certificates
representing  such Warrant  Shares  shall have  stamped or imprinted  thereon or
affixed thereto a legend to the following effect:

                  The securities  represented by this  certificate have not been
         registered  under the  Securities  Act of 1933 or any state  securities
         laws and may not be sold,  transferred or otherwise  disposed of in the
         absence  of  registration  under  such laws or an  opinion  in form and
         substance   acceptable   to  the  Company   from   counsel   reasonably
         satisfactory to the Company to the effect that no such  registration is
         required.

                  (e) State  Securities  Laws.  This Warrant has been offered to
and accepted by the Registered  Holder at its principal  executive office in the
State of Florida and has not been offered to the Registered  Holder in any other
State.

         6. Adjustments to the Purchase Price and Number of Warrant Shares.

                  (a)  Subdivision  of  Stock,  etc.  In the  event  of a  stock
dividend or other  distribution  payable in Common Stock,  or any stock split or
subdivision  of Common  Stock  into a greater  number of  shares,  the number of
Warrant Shares subject to the Warrant  immediately  prior to such event shall be
proportionately  increased and the Purchase Price in effect immediately prior to
such  event  shall  be  proportionately  reduced,  and in  the  event  that  the
outstanding  shares of Common  Stock of the  Company  shall be  combined  into a
smaller  number of shares,  the number of Warrant  Shares subject to the Warrant
immediately prior to such combination shall be  proportionately  reduced and the
Purchase  Price  in  effect  immediately  prior  to such  combination  shall  be
proportionately increased.

                  (b) Reorganization,  Consolidation,  Merger, etc. In the event
that the Company shall (i) effect a reorganization or recapitalization  pursuant
to which all of the outstanding shares





                                       6


of Common Stock are converted into or exchanged for other securities or property
(including cash), (ii) consolidate with or merge into any other person, or (iii)
transfer  all or  substantially  all of its  properties  or  assets to any other
person in such a way that  holders of Common  Stock shall be entitled to receive
securities  or property  (including  cash) with  respect to or in  exchange  for
Common Stock;  then,  in each such case,  the  Warrantholder,  upon the exercise
hereof as  provided  in  Section 2 at any time  after the  consummation  of such
reorganization or recapitalization,  consolidation, merger or sale of assets, as
the case may be, shall be entitled to receive (and the Company shall be required
to deliver) in lieu of the Warrant  Shares  issuable upon such exercise prior to
such and other  securities  and property  (including  cash) to which such holder
would have been entitled upon such  consummation,  if such  Warrantholder had so
exercised this Warrant  immediately  prior thereto.  The above  provision  shall
apply to successive reorganizations, recapitalizations,  consolidations, mergers
or transfers described therein. Notwithstanding the foregoing, in the event of a
merger between the Company and Lab Holdings,  Inc. prior to the exercise hereof,
then upon the exercise hereof as provided in Section 2, the Warrantholder  shall
be entitled to receive (and the Company  shall be required to deliver),  in lieu
of the Warrant Shares  issuable upon such exercise,  the securities to which the
Warrantholder  would  have  been  entitled  upon  such  consummation,   if  such
Warrantholder had so exercised this Warrant immediately prior to such merger.

         7. Notice of Record Date, Etc.. In the event of:

                  (a) any taking by the  Company  of a record of the  holders of
Common Stock for the purpose of determining the holders thereof who are entitled
to receive any dividend  (excluding any cash dividend payable out of earnings or
earned  surplus of the  Company),  or any right to  subscribe  for,  purchase or
otherwise  acquire any shares of stock of any class or any other  securities  or
property, or to receive any other right, or

                  (b) any transfer of all or substantially  all of the assets of
the Company to or  consolidation or merger of the Company with or into any other
person, or

                  (c) any voluntary or involuntary  dissolution,  liquidation or
winding-up of the Company,

then and in each event the Company shall cause to be mailed to the Warrantholder
a notice containing a brief description of the





                                       7


proposed action and stating the date on which either a record is to be taken for
the purpose of such  dividend,  distribution  or rights,  or the date upon which
such transfer, consolidation,  merger, dissolution, liquidation or winding-up is
to take place and the time,  if any is to be fixed,  as of which the  holders of
Common  Stock  or  other   securities  shall  receive  cash  or  other  property
deliverable upon such transfer, consolidation,  merger, dissolution, liquidation
or  winding-up.  Such notice shall also state that the action in question or the
record date is subject to the  effectiveness  of a registration  statement under
the Securities Act or a favorable vote of  stockholders,  if either is required.
Such notice shall be mailed to the Warrantholder at least ten (10) days prior to
the date specified in such notice on which any such action is to be taken or the
record date, whichever is earlier.

         8. Reservation of Warrant Shares; Authority;  Validity. During the term
of this Warrant,  the Company shall at all times reserve and keep available from
its  authorized  but  unissued or  treasury  shares such number of shares of its
Common Stock as shall be issuable upon exercise of the Warrant.  The Company has
all requisite corporate power and authority to execute, deliver, and perform its
obligations  under this Warrant.  Upon the Company's  execution of this Warrant,
this Warrant shall have been duly authorized, executed, and delivered, and shall
constitute legal, valid, and binding obligations of the Company,  enforceable in
accordance with its terms.

         9. Listing or Qualification for Trading. The Company shall use its best
efforts  to cause  the  Warrant  Shares,  immediately  upon  official  notice of
issuance upon exercise of this Warrant,  to be listed or admitted for trading on
such  principal  securities  exchange,  interdealer  quotation  system or market
within the United  States of America,  if any,  on which other  shares of Common
Stock are then listed or quoted,  and to maintain such listing or  qualification
for  trading  for so long as other  shares of Common  Stock are listed or quoted
thereon.  The Company is under no obligation to register or qualify this Warrant
or the Warrant Shares under the Securities Act or any state securities laws.

         10. Notices.  Any notice or other document  required or permitted to be
given or delivered to the  Registered  Holder shall be delivered  at, or sent by
certified or registered mail to the Registered  Holder at the last address shown
on the books of the Company  maintained  for the  registry  and  transfer of the
Warrants.






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         11.  No Rights as  Stockholder.  This  Warrant  shall not  entitle  the
Registered Holder to any voting or other rights as a stockholder of the Company.

         12.  Replacement  of  Warrant.  Upon  receipt  of  evidence  reasonably
satisfactory  to the Company of the loss,  theft,  destruction  or mutilation of
this Warrant and, in the case of such loss, theft or destruction,  upon delivery
of an indemnity bond  reasonably  satisfactory in form and amount to the Company
or, in the case of any such mutilation,  upon surrender and cancellation of such
Warrant, the Company at its expense will execute and deliver, in lieu thereof, a
new Warrant of like tenor.

         13. Law Governing. This Warrant shall be governed by, and construed and
enforced in accordance  with,  the laws of the State of Delaware  (excluding the
choice of law provisions thereof).

         14.  Miscellaneous.  This  Warrant  and  any  provision  hereof  may be
changed,  waived,  discharged  or  terminated  only by an  instrument in writing
signed by the party (or any  predecessor  in  interest  thereof)  against  which
enforcement of the same is sought. The headings in this Warrant are for purposes
of reference only and shall not affect the meaning or construction of any of the
provisions hereof.

              IN  WITNESS  WHEREOF, this Warrant is executed effective as of the
day and year first above written.


                                  LABONE, INC.



                                  By:
                                     W. Thomas Grant II
                                     Its Chairman of the Board, President,
                                     and Chief Executive Officer





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                  NOTICE OF INTENTION TO EXERCISE WARRANT ____


         The  undersigned  hereby notifies  LabOne,  Inc. that he has elected to
exercise  its right  under the within  Warrant to  purchase  ________  shares of
Common  Stock,  and has  effected a wire  transfer  to LabOne,  Inc. or enclosed
herewith cash or a cashier's  check payable to LabOne,  Inc. in the total amount
of  $_________  in  payment  of  the  Purchase   Price  for  such  shares.   The
certificate(s) representing the shares of Common Stock being purchased should be
delivered in the denominations and to the persons described below:

                                                                   No. of
            Name                        Address                    Shares
            ----                        -------                    ------











                                          HEALTHPLAN SERVICES, INC.


Date:                                     By:
     ----------------------                  -------------------------------
                                                     (Signature)



                                             -------------------------------
                                                     (Print Name)



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                                                        (Title)