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                                                                   Exhibit 10.15









                                  APBIOTECH INC


                         US EMPLOYEE STOCK PURCHASE PLAN






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                                    ARTICLE I
                                  Introduction

      Sec. 1.01 Statement of Purpose. The purpose of the APBiotech Inc US
Employee Stock Purchase Plan is to provide eligible employees of certain United
States subsidiaries of the Company, who wish to become shareholders, an
opportunity to purchase Stock in Company. The Board of Directors of the Company
believes that employee participation in stock ownership will be to the mutual
benefit of the employees and the Company.

      Sec. 1.02 Internal Revenue Code Considerations. The Plan is intended to
constitute an "employee stock purchase plan" within the meaning of section 423
of the Internal Revenue Code of 1986, as amended. The Plan will be approved by
the Company's shareholders within 12 months of the Plan being adopted by the
Board of Directors.

      Sec. 1.03 ERISA Considerations. The Plan is not intended and shall not be
construed as constituting an "employee benefit plan," within the meaning of
section 3(3) of the Employee Retirement Income Security Act of 1974, as amended.


                                   ARTICLE II
                                   Definitions


      Sec. 2.01 "Shares" means shares in the Company's Common Stock, $0.01 par
value.

      Sec. 2.02 "Board of Directors" means the board of directors of the Company
or a committee of the board of directors authorized to act on its behalf.

      Sec. 2.03 "Code" means the Internal Revenue Code of 1986, as amended, and
any successor statute of similar nature. References to specific sections of the
Code shall be taken to be references to corresponding sections of any successor
statute.

      Sec. 2.04 "Committee" means the committee appointed by the Board of
Directors to administer the Plan, as provided in Section 6.03 hereof, or any
delegate of that committee.

      Sec. 2.05 "Company" means APBiotech Inc.

      Sec. 2.06 "Effective Date" means January 1, 2001.

      Sec. 2.07 "Election Date" means each January 1 and July 1 or such other
dates as the Committee shall specify.

                  Sec. 2.08 "Eligible Employee" means each person employed as an
employee of an Employer who (a)(i) has been employed by an Employer for not less
than three (3) months and (ii) is customarily employed for more than twenty (20)
hours per week, and (b) is not


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deemed for purposes of section 423(b) (3) of the Code to own stock possessing
five percent or more of the total combined voting power or value of all classes
of stock of the Company or any Subsidiary.

      Sec. 2.09 "Employer" means each Subsidiary.

      Sec. 2.10 "Exchange Act" means the Securities Exchange Act of 1934, as
amended, and as the same may hereafter be amended.

      Sec. 2.11 "Market Value" means the last price for the Shares as reported
on NASDAQ for the date of reference. If there was no such price reported for the
date of reference, "Market Value" means the "Market Value" as of the date next
preceding the date of reference for which such price was reported.

      Sec. 2.12 "Participant" means each Eligible Employee who elects to
participate in the Plan.

      Sec. 2.13 "Plan" means the APBiotech Inc US Employee Stock Purchase Plan,
as the same is set forth herein and as the same may hereafter be amended.

      Sec. 2.14 "Purchase Agreement" means the instrument prescribed by the
Committee pursuant to which an Eligible Employee may enroll as a Participant and
subscribe for the purchase of Shares on the terms and conditions offered by the
Company. The Purchase Agreement also is intended to evidence the Company's offer
of an option to the Eligible Employee to purchase Shares on the terms and
conditions set forth therein and herein.

      Sec. 2.15 "Purchase Date" means June 30, 2001 and the last business day of
each Purchase Period ending thereafter.

      Sec. 2.16 "Purchase Period" means, beginning January 1, 2001, each
six-calendar month period or other period specified by the Committee during
which the Participant's stock purchase is funded through payroll deduction
accumulations.

      Sec. 2.17 "Subsidiary" means any present or future corporation (i) which
constitutes a "subsidiary corporation" of the Company as that term is defined in
section 424 of the Code, and (ii) is designated as a participating entity in the
Plan by the Committee. Unless the Committee specifically designates otherwise, a
subsidiary not incorporated and resident in the United States shall not be
considered a Subsidiary for purposes of the Plan, and employees of such a
subsidiary shall not be Eligible Employees.

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                                   ARTICLE III
                           Admission to Participation

      Sec. 3.01 Initial Participation. Any Eligible Employee may elect to
participate in the Plan and may become a Participant by executing and filing
with the Committee a Purchase Agreement at such time in advance of any
subsequent Election Date as the Committee shall prescribe. An Eligible
Employee's initial election to participate in the Plan may be made at any time
after he or she first becomes eligible to participate in the Plan and shall be
effective as of the next Election Date after the Eligible Employee submits in a
timely manner the necessary documentation to the Committee. After an Eligible
Employee has first become a Participant in the Plan, subsequent elections to
participate in the Plan shall be made pursuant to Section 3.03. A Participants'
Purchase Agreement shall remain in effect until modified or canceled in
accordance with the further terms of this Plan, as hereinafter set forth.

      Sec. 3.02 Discontinuance of Participation. A Participant may voluntarily
cease his or her participation in the Plan and stop payroll deductions at any
time by filing a notice of cessation of participation on such form and at such
time in advance of the effective date as the Committee shall prescribe.
Notwithstanding anything in the Plan to the contrary, if a Participant ceases to
be an Eligible Employee, his or her participation automatically shall cease and
no further purchase of shares shall be made for such Participant hereunder. In
either case, if a Participant ceases participation in the Plan before the end of
the then current Purchase Period, any amounts held for purchase of shares on
behalf of the Participant on the next subsequent Purchase Date shall be refunded
to the Participant.

      Sec. 3.03 Readmission to Participation. Any Eligible Employee who has
previously been a Participant, who has discontinued participation (whether by
cessation of eligibility or otherwise), and who wishes to be reinstated as a
Participant may again become a Participant by executing and filing with the
Committee a new Purchase Agreement. Reinstatement to Participant status shall be
effective as of any Election Date, provided the Participant files such new
Purchase Agreement with the Committee at such time in advance of such Election
Date as the Committee shall prescribe.



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                                   ARTICLE IV
                            Share Purchase and Resale

      Sec. 4.01 Reservation of Shares.

            (a) The maximum number of Shares which shall be issued under the
Plan (subject to adjustment in the capitalization of the Company in accordance
with Section 5.02 below) shall be 600,000 Shares.

            (b) Notwithstanding Section 4.01(a) above, the number of Shares that
may be purchased under the Plan in any calendar year, shall not exceed the
lesser of (i) the annual limit on such Shares, if any, established by the
Committee from time to time, or (ii) the number of Shares that would cause the
number of Shares in the Company which shall have been or may be issued in
pursuance of options or which have been or may issued otherwise than in
pursuance of options, under the Plan or under any other employees' share scheme
adopted by the Company, to exceed such number as represents 3% of the ordinary
share capital of the Company in issue at that time.

            (c) The limit at Section 4.01(b)(ii) above shall apply from the date
of adoption of the Plan by the Company until such date as determined by the
Committee, which shall not be before 1 June 2002 at the earliest.

            (d) Only those Shares which are capable of being issued before 1
June 2002 (or such later date as determined by the Directors pursuant to Section
4.01(c) above) on the exercise of any options or other awards will be relevant
for the purposes of calculating the limit in Section 4.01(b)(ii) above, and
Shares shall not be regarded as being capable of being issued by reason of any
provisions in the relevant employees' share schemes under which such options or
awards are granted allowing a person to exercise an option or award in
circumstances of leaving employment or a change of control of the Company.

      Sec. 4.02 Limitation on Shares Available.

            (a) Subject to the limitations of Section 4.04, the maximum number
of Shares that may be purchased for each Participant on a Purchase Date is the
lesser of (i) the number of whole and fractional Shares that can be purchased by
applying the full balance of the Participant's withheld funds to the purchase of
Shares at the Purchase Price, or (ii) the Participant's proportionate part of
the maximum number of Shares available under the Plan, as stated in Section
4.01.

            (b) Notwithstanding the foregoing, if any person entitled to
purchase Shares pursuant to any offering under the Plan would be deemed for
purposes of section 423(b)(3) of the Code to own stock (including any number of
Shares that such person would be entitled to purchase under the Plan) possessing
five percent or more of the total combined voting power or value of all classes
of stock of the Company, the maximum number of Shares that such person shall be
entitled to purchase pursuant to the Plan shall be reduced to that number which,
when added to the number of Shares of stock that such person is deemed to own
(excluding any number of Shares that such person would be entitled to purchase
under the Plan), is one less than



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such five percent. Any amounts withheld from a Participant's compensation that
cannot be applied to the purchase of Shares by reason of the foregoing
limitation or the limitation set forth in Section 4.02(a)(ii) shall be returned
to the Participant as soon as practicable.

      Sec. 4.03 Purchase Price of Shares. The Purchase Price per Share sold to
Participants pursuant to any offering hereunder shall be the lower of (i) 85% of
the Market Value per Share on the first day of the Purchase Period or (ii) 85%
of the Market Value per Share on the Purchase Date. Notwithstanding the
foregoing, the Board of Directors may determine that the Purchase Price for any
subsequent Purchase Period shall be the Market Value, or a percentage of the
Market Value on either of such dates or the lower of such dates, so long as such
percentage shall not be lower than 85% of such Market Value.

      Sec. 4.04 Exercise of Purchase Privilege.

            (a) Each Participant shall be granted an option to purchase Shares
as of the first day of each Purchase Period at the Purchase Price specified in
Section 4.03. The option shall continue in effect through the Purchase Date for
the Purchase Period. Subject to the provisions of Sections 3.02 and 4.02 above
and Sections 4.04(c) and 4.05 below, on each Purchase Date, the Participant
shall be automatically deemed to have exercised his or her option to purchase
Shares on the Purchase Date, unless he or she notifies the Committee, in such
manner and at such time in advance of the Purchase Date as the Committee shall
prescribe, of his or her desire not to make such purchase.

            (b) There shall be purchased for the Participant on such Purchase
Date at the Purchase Price for such Purchase Period the largest number of whole
and fractional Shares as can be purchased with the amounts withheld from the
Participant's compensation during the Purchase Period. Each such purchase shall
be deemed to have occurred on the Purchase Date occurring at the close of the
Purchase Period for which the purchase was made. Any amounts withheld from a
Participant's compensation during a Purchase Period that are not applied to
purchase Shares on the Purchase Date occurring at the close of that Purchase
Period shall be retained and applied to purchase Shares on the next subsequent
Purchase Date.

            (c) Notwithstanding the foregoing, a Participant may not purchase
Shares having an aggregate Market Value of more than $25,000, determined at the
beginning of each Purchase Period, for any calendar year in which one or more
such offerings are outstanding at any time, and a Participant may not purchase a
Share under any offering after the expiration of the Purchase Period for such
offering.

      Sec. 4.05 Payroll Deductions. Each Participant shall authorize payroll
deductions from his or her base pay for the purpose of funding the purchase of
Shares pursuant to his or her Purchase Agreement. In the Purchase Agreement,
each Participant shall authorize an after-tax payroll deduction from each
payment of his base pay during a Purchase Period, of an amount not less than $5
per paycheck and not more than a percentage of such Participant's base pay
determined by the Committee and communicated to Eligible Employees before the
beginning of that Purchase Period. A Participant may change the deduction to any
permissible level effective as of any Election Date. Such change shall be made
by the Participant's filing



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with the Committee a notice in such form and at such time in advance of the date
on which such change is to be effective as the Committee shall prescribe.

      Sec. 4.06 Payment for Shares. The Purchase Price for all Shares purchased
by a Participant under the Plan shall be paid out of the Participant's
authorized payroll deductions. All funds received or held by the Company under
the Plan are general assets of the Company, free of any trust or other
restriction, and may be used for any corporate purpose.

      Sec. 4.07 Share Ownership; Issuance of Certificates.

            (a) The Shares purchased by a Participant on a Purchase Date shall,
for all purposes, be deemed to have been issued or transferred at the close of
business on such Purchase Date. Prior to that time, none of the rights or
privileges of a shareholder of the Company shall inure to the Participant with
respect to such Shares. All the Shares purchased under the Plan shall be
delivered by the Company in a manner as determined by the Committee.

            (b) The Committee, in its sole discretion, may determine that the
Shares shall be delivered by the Company by (i) issuing and delivering to the
Participant a certificate for the number of Shares purchased by such Participant
on a Purchase Date or during a calendar year or other period determined by the
Committee, (ii) issuing and delivering a certificate or certificates for the
number of Shares purchased by all Participants on a Purchase Date or during a
calendar year or other period determined by the Committee to a firm which is a
member of the National Association of Securities Dealers, as selected by the
Committee from time to time, which shares shall be maintained by such firm in
separate brokerage accounts of each Participant, or (iii) issuing and delivering
a certificate or certificates for the number of Shares purchased by all
Participants on a Purchase Date or during the calendar year or other period
determined by the Committee to a bank or trust company or affiliate thereof, as
selected by the Committee from time to time, which shares may be held by such
bank or trust company or affiliate in "street name," but with separate accounts
maintained by such entity for each Participant reflecting such Participant's
interests in the Shares. Each certificate or account, as the case may be, shall
be in the name of the Participant.

            (c) In addition to any restrictions or limitations on the resale of
Shares purchased under the Plan set forth in Section 4.08 hereof or otherwise
hereunder, the Committee, in its sole discretion, may impose such restrictions
or limitations, as it shall determine, on the resale of Shares, the issuance of
individual stock certificates or withdrawal from any shareholder accounts
established for a Participant pursuant to the terms hereof.

            (d) Any dividends payable with respect to whole or fractional Shares
credited to a shareholder account of a Participant established pursuant to
Section 4.07(b) hereof will be reinvested in Shares and credited to such
Participant's account. Such reinvestment shall be made based on the Market Value
of the Shares on the date of the reinvestment, with no discount from Market
Value.

      Sec. 4.08 Withdrawal of Shares or Resale of Shares


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            (a) A Participant may (i) sell any Shares purchased hereunder by
requesting the sale of those Shares at any time in such form and at such time as
the Committee shall prescribe, or (ii) withdraw his or her Shares from any
shareholder account established pursuant to Section 4.07(b) hereof by requesting
the withdrawal of those Shares in such form and at such time as the Committee
shall prescribe, but not earlier than the second anniversary of the first day of
the Purchase Period for which options to purchase such Shares were granted.

            (b) If a Participant is to receive a withdrawal of Shares, the
withdrawal shall be paid in whole Shares, with fractional Shares paid in cash.

                                    ARTICLE V
                               Special Adjustments

      Sec. 5.01 Shares Unavailable. If, on any Purchase Date, the aggregate
funds available for the purchase of Shares would purchase a number of Shares in
excess of the number of shares then available for purchase under the Plan, the
following events shall occur:

            (a) The number of Shares that would otherwise be purchased by each
      Participant shall be proportionately reduced on the Purchase Date in order
      to eliminate such excess; and

            (b) The Plan shall automatically terminate immediately after the
      Purchase Date as of which the supply of available Shares is exhausted.

      Sec. 5.02 Anti-Dilution Provisions. The aggregate number of Shares
reserved for purchase under the Plan, as hereinabove provided, and the
calculation of the Purchase Price per Share may be appropriately adjusted to
reflect any increase or decrease in the number of issued Shares resulting from a
subdivision or consolidation of Shares or other capital adjustment, or the
payment of a stock dividend, or other increase or decrease in such Shares, if
effected without receipt of consideration by the Company. Any such adjustment
shall be made by the Committee acting with the consent of, and subject to the
approval of, the Board of Directors.

      Sec. 5.03 Effect of Certain Transactions. Subject to any required action
by the shareholders, if the Company shall be the surviving or resulting
corporation in any merger or consolidation, any offering hereunder shall pertain
to and apply to the Shares of the Company. In the event of a merger or
consolidation in which the Company is not the surviving or resulting
corporation, the Purchase Date for the Purchase Period during which such
transaction shall occur shall be the last business day preceding the closing
date for such transaction. In the event of a dissolution or liquidation of the
Company, the Plan and any offering hereunder shall terminate upon the effective
date of such dissolution, liquidation, merger or consolidation, and the balance
of any amounts withheld from the Participant's compensation, which had not by
such time been applied to the purchase of Shares shall be returned to the
Participant.


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                                   ARTICLE VI
                                 Miscellaneous.

      Sec. 6.01 Non-Alienation. The right to purchase Shares under the Plan is
personal to the Participant, is exercisable only by the Participant during the
Participant's lifetime except as hereinafter set forth, and may not be assigned
or otherwise transferred by the Participant. Notwithstanding the foregoing,
there shall be delivered to the executor, administrator or other personal
representative of a deceased Participant such Shares and such residual amounts
as may remain to the Participant's credit from amounts withheld from the
Participant's compensation as of the Purchase Date occurring at the close of the
period in which the Participant's death occurs, including Shares purchased as of
that date or prior thereto with moneys withheld from the Participant's
compensation.

      Sec. 6.02 Administrative Costs. The Company shall pay all Company related
administrative expenses, including stamp duty, associated with the operation of
the Plan.

      Sec. 6.03 The Committee. The Board of Directors shall appoint a Committee,
which shall have the authority and power to administer the Plan and to make,
adopt, construe, and enforce rules and regulations not inconsistent with the
provisions of the Plan. The Committee shall adopt and prescribe the contents of
all forms required in connection with the administration of the Plan, including,
but not limited to, the Purchase Agreement, payroll withholding authorizations,
withdrawal documents, and all other notices required hereunder. The Committee
shall have the fullest discretion permissible under law in the discharge of its
duties. The Committee's interpretations and decisions in respect of the Plan,
the rules and regulations pursuant to which it is operated, and the rights of
Participants hereunder shall be final and conclusive.

                  Sec. 6.04 Withholding of Taxes. All acquisitions of Shares
under the Plan shall be subject to applicable federal, state and local tax
withholding requirements if the Internal Revenue Service or other taxing
authority requires such withholding. The Company may require that Participants
pay to the Company (or make other arrangements satisfactory to the Company for
the payment of) the amount of any federal, state or local taxes that the Company
is required to withhold with respect to the purchase of Shares or the sale of
Shares acquired under the Plan, or the Company may deduct from the Participants
wages or other compensation the amount of any withholding taxes dues with
respect to the purchase of Shares or the sale of Shares acquired under the Plan.

      Sec. 6.05 Amendment of the Plan. The Board of Directors (or its delegate)
may amend or terminate the Plan at any time; provided, however, that the Board
of Directors (or its delegate)

            (a) shall not amend the Plan without stockholder approval if such
      approval is required by section 423 of the Code, and

            (b) shall not amend provisions relating to eligibility, limits on
      the purchase or availability of Shares, or other material Participant
      entitlements, where such amendments would be to the advantage of
      Participants, without prior stockholder approval

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      (provided that this requirement to obtain stockholder approval will not
      apply to any minor amendment to benefit the administration of the Plan, to
      take account of a change in legislation or to obtain or maintain
      favourable tax, exchange control, or regulatory treatment for Participants
      or the Company or any Subsidiary).

      Sec. 6.06 Expiration and Termination of the Plan. The Plan shall continue
in effect for 10 years from the date the Plan is approved by stockholders,
unless terminated prior thereto pursuant to the provisions of the Plan or
pursuant to action by the Board of Directors, which shall have the right to
terminate the Plan at any time without prior notice to any Participant and
without liability to any Participant. Upon the expiration or termination of the
Plan, the balance, if any, then standing to the credit of each Participant from
amounts withheld from the Participant's compensation which had not, by such
time, been applied to the purchase of Shares shall be refunded to the
Participant.

      Sec. 6.07 Repurchase of Shares. The Company shall not be required to
purchase or repurchase from any Participant any of the Shares that the
Participant acquired under the Plan.

      Sec. 6.08 Notice. A Purchase Agreement and any notice that a Participant
files pursuant to the Plan shall be on the form prescribed by the Committee and
shall be effective only when received by the Committee. Delivery of such forms
may be made by hand or by certified mail, sent postage prepaid. Forms shall be
addressed to Director of Compensation, Amersham Pharmacia Biotech, Inc., 80
Centennial Avenue, P. O. Box 1327, Piscataway, N.J. 08855. Delivery by any other
mechanism shall be deemed effective at the option and discretion of the
Committee.

      Sec. 6.09 Government Regulation. The Company's obligation to sell and to
deliver the Shares under the Plan is at all times subject to all approvals of
any governmental authority required in connection with the authorization,
issuance, sale or delivery of such Shares.

      Sec. 6.10 Headings, Captions, Gender. The headings and captions herein are
for convenience of reference only and shall not be considered as part of the
text. The masculine shall include the feminine, and vice versa.

      Sec. 6.11 Severability of Provisions, Prevailing Law. The provisions of
the Plan shall be deemed severable. In the event any such provision is
determined to be unlawful or unenforceable by a court of competent jurisdiction
or by reason of a change in an applicable statute, the Plan shall continue to
exist as though such provision had never been included therein (or, in the case
of a change in an applicable statute, had been deleted as of the date of such
change). The Plan shall be governed by the laws of the State of New Jersey to
the extent such laws are not in conflict with, or superseded by, federal law.


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