Exhibit 10.18

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:  50,000                                     Warrant No. _______
Original Issue Date:  May 14, 1999


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


                  This certifies  that, for value  received,  STC  TECHNOLOGIES,
INC. ("STC") 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 50,000  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)  "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.

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

                  (c)  "Expiration  Date" shall mean 12:01 o'clock a.m.  Central
Daylight Time on July 13, 2001, which is eight (8) calendar  quarters plus sixty
(60) days after the date hereof.

                  (d) "Purchase  Price" or "Purchase Price per share" shall mean
the purchase price per Warrant Share (as defined below), which shall equal $.01.

                  (e)  "Warrantholder" or "Registered Holder" shall mean STC, or
its registered transferee.




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

                  (g)  "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.       Exercise of Warrant.

                  (a) Subject to the terms and conditions  hereof,  this Warrant
may be  exercised  only on or after the date which is one year from the Original
Issue Date of this Warrant, and prior to 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 to the Corporate  Secretary of
the Company at the Company's office located at 10310 West 84th Terrace,  Lenexa,
Kansas  66214 (or such other  office or agency of the Company as the Company may
designate by notice in writing to the Registered Holder) either

(i)  this Warrant, the Notice Form completed to reflect an exercise for cash 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, or

(ii) this  Warrant,  the Notice Form  completed  to reflect a cashless  exercise
     without any payment of cash, cashier's check or wire-transferred  funds, in
     which case the  Company  shall issue to the  Registered  Holder a number of
     shares of Common Stock computed using the following formula:

                                    X =       Y(A-B)
                                              ------
                                                A

         Where:
               X = the  number  of  shares  of  Common  Stock  to be issued.
               Y = the number of Warrant Shares exercised by Warrantholder.
               A = the fair market value of one share of Common Stock.
               B = Purchase Price per share.

                  As used in this  section,  the fair market value of the Common
                  Stock shall mean,  with respect to each share of Common Stock,
                  the  average of the  closing  prices of the  Company's  Common
                  stock  sold on all  securities  exchanges  on which the Common
                  Stock may at the time be listed (including,  for this purpose,
                  the  NASDAQ  National  Market),  or, if at any time the Common
                  Stock is not so listed,


                                        2



         the average of the  representative  bid and asked prices  quoted in the
         NASDAQ system as of 4:00 p.m.,  New York City time,  or, if at any time
         the Common Stock is not quoted in the NASDAQ System, the average of the
         highest  bid and lowest  asked price in the  domestic  over-the-counter
         market as reported by the National Quotation Bureau,  Incorporated,  or
         any  similar  successor  organization,  in each such case on the day on
         which the Notice of  Exercise  is received or if no sales of the Common
         Stock have occurred on date, on the next  preceding date on which there
         were such sales.  If at any time the Common  Stock is not listed on any
         securities   exchange   or   quoted  in  the   NASDAQ   System  or  the
         over-the-counter  market,  the fair  market  value of the Common  Stock
         shall be the highest  price per share which the  Company  could  obtain
         from a willing buyer (who is not a current  employee or director) for a
         share of Common Stock sold by the Company, from authorized but unissued
         shares,  as  determined  in good faith by the Board of Directors of the
         Company.

In no event may the Warrantholder exercise the Warrant with respect to more than
50,000  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 and, in any event,  within ten (10)
days  after  each such  exercise,  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.       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)  Transfer.  This  Warrant  and all  rights  hereunder  are
transferable  in whole or in part  upon the  surrender  of this  Warrant  with a
properly executed  assignment at the principal office of the Company;  provided,
however,  that this Warrant and  Warrantholder's  rights  thereunder  are in all
respects subject to all provisions of Section 5, including but not limited to

                                        3



the requirement in Section 5(c).

                  (c) Exchange of Warrant Upon a Transfer.  On surrender of this
Warrant for exchange,  together with a properly endorsed Assignment, and subject
to the  provisions  of this  Warrant  including  all  provisions  of  Section 5,
including but not limited to the requirement in Section 5(c), the Company at its
expense shall issue to or on the order of the Registered Holder a new warrant or
warrants of like tenor,  in the name of the  Registered  Holder or as the Holder
(on payment by the Holder of any applicable  transfer taxes) may direct, for the
number of shares of Common Stock issuable upon exercise hereof.

         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)  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 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

                                        4




         reasonably  satisfactory  to  the  Company  to  the effect that no such
         registration is required.

However,  if the Company receives an opinion acceptable in form and substance to
the Company from counsel reasonably  satisfactory to the Company,  or an opinion
of counsel to the Company, to the effect that any stop transfer order or legends
may be removed  without  violation of  applicable  law,  then the Company  shall
instruct  its  transfer  agent to remove any such stop  transfer  order and such
legends.

                  (e) State  Securities  Laws.  This Warrant has been offered to
and accepted by the Registered  Holder at its principal  executive office in the
Commonwealth of Pennsylvania  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 other  securities
convertible  into or exchangeable for shares of 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 (a) effect a reorganization or recapitalization  pursuant
to which all of the  outstanding  shares of Common Stock are  converted  into or
exchanged for other  securities or property  (including  cash),  (b) consolidate
with or merge into any other person, or (c) 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  the  securities  and  property
(including  cash) to which the Warrant 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.

         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

                                        5


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 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.  Liquidating  Dividends.  If the Company  pays a dividend or makes a
distribution on the Common Stock payable  otherwise then in cash out of earnings
or earned surplus  (determined in accordance with generally accepted  accounting
principles)  except for a stock  dividend  payable in shares of Common  Stock (a
"Liquidating  Dividend"),  then  the  Company  will  pay  or  distribute  to the
Registered Holder of this Warrant,  upon the exercise hereof, in addition to the
Warrant  Shares  purchased upon such exercise,  the  Liquidating  Dividend which
would  have  been  paid to such  Registered  Holder  if he had been the owner of
record of such Warrant Shares immediately prior to the date on which a record is
taken for such  Liquidating  Dividend or, if no record is taken,  the date as of
which  the  record  holders  of  Common  Stock  entitled  to such  dividends  or
distribution are to be determined.

         9. Reservation of Warrant Shares.  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.

         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.

         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,

                                        6


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



























                                        7


                  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, if "Cash  Exercise" is checked  below,  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
         ----                        -------                        ------







Check one of the following:
_____ Cash Exercise
_____ Cashless Exercise


STC TECHNOLOGIES, INC.


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


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


                                                 ---------------------------
                                                 (Title)