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                                                                  EXHIBIT 10(1)
              
                    Employment Agreement of J. David Tholen

                              EMPLOYMENT AGREEMENT

         THIS EMPLOYMENT AGREEMENT ("Agreement") is made and entered into by
HYCOR BIOMEDICAL INC., a Delaware corporation ("Company"), and J. DAVID THOLEN
("Tholen").

         WHEREAS, the Company desires to promote Tholen from Executive Vice
President to President and Chief Executive Officer, Tholen desires to accept
such employment, and the parties desire to memorialize the terms and conditions
of their employment relationship,

         NOW, THEREFORE, in consideration of the promises and covenants set
forth in this Agreement and for other valuable consideration, the parties agree
as follows:

               1. Prior Agreement: This Agreement supercedes and replaces in its
entirety the Employment Agreement executed January 12, 1998 and re-executed as
of December 10, 1998 between Tholen and the Company.

               2. Employment: Tholen shall be employed as President and Chief
Executive Officer of the Company reporting to the Chairman, and shall faithfully
and diligently perform all duties and responsibilities required of such position
based upon the general direction of the Board of Directors from time to time,
including service on behalf of the Company's subsidiary and affiliated
companies. The Board's current direction is as follows: to improve overall
performance leading to increased stock price.

               3. Term. This Agreement and Tholen's employment as President and
Chief Executive Officer shall be for a term of two (2) years commencing on June
17, 1998, and expiring on June 16, 2000. Thereafter, the parties may renew this
Agreement upon mutually agreeable terms and conditions.

               4. Compensation: In consideration for all services to be
performed under this Agreement, Tholen shall receive the following compensation:

                    a. Salary: Tholen shall be paid base salary at the rate of
One Hundred Eighty-Five Thousand Dollars ($185,000) per year until his first
regular review in January, 1999 and annually thereafter, at which time the Board
of Directors shall review Tholen's performance with a view toward increasing his
salary commensurate with such performance.

                    b. Bonus: Tholen shall annually submit, within ten (10) days
prior to the commencement of a new fiscal year, a Bonus Plan to the Compensation

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Committee of the Board of Directors for approval, under which Tholen shall
participate, based upon obtaining the agreed upon revenue, profit and stock
price milestones. Nothing herein or in said plan shall constitute a guarantee of
Tholen's employment by the Company, or a limitation on the Company's rights
under this Agreement, or limitation on the Company's rights to amend or
terminate such plan.

                    c. Employee Benefit Plans: Tholen shall be entitled to
participate in all employee benefit plans, including group medical, dental,
visual, and life insurance, pension, profit sharing, group and individual
disability income, stock option, and other benefit plans, on terms commensurate
with the benefits awarded management personnel of comparable status with the
Company or any affiliate of the Company, but subject, on any termination, to
Section 5E below.

                    d. Expense Reimbursement:

                         (a) Relocation Expenses. The Company shall reimburse
Tholen on a monthly basis for his monthly lease obligations for rent and
utilities (not to exceed $2,500/month) for a furnished apartment in Southern
California for up to two (2) years provided that Tholen remains employed
hereunder. In the event Tholen relocates in connection with his continued
employment with the Company, the Company shall pay directly or shall reimburse
Tholen for his reasonable relocation expenses upon satisfactory proof thereof,
up to a maximum of $50,000.

                         (b) Regular Expenses. The Company shall reimburse
Tholen for all reasonable expenses that he necessarily incurs in connection with
his employment and for which he presents adequate documentation in accordance
with Company policies in effect from time to time.

               5. Termination: This Agreement and Tholen's employment are
subject to immediate termination at any time as follows:

                    a. Death: This Agreement shall terminate immediately upon
Tholen's death, in which event the Company's only obligations shall be (i) to
pay all compensation owing for services rendered by Tholen prior to the date of
his death; (ii) to continue paying Tholen's base salary to his estate for a
period of thirty (30) days after his death; and (iii) to make periodic
recoverable advances to Tholen's estate equivalent to Tholen's base salary for
ninety (90) days after said thirty (30) day period has lapsed, with such
advances to be repaid when insurance proceeds from a policy on Tholen's life
become available.

                    b. Disability: In the event that Tholen is disabled from
performing his assigned duties under this Agreement due to illness or injury for
a period in excess of one hundred eighty (180) days, the Company may place
Tholen on an unpaid leave of absence for a period not to exceed six (6) months,
in which case the Company's only obligation shall be (i) to continue Tholen's
group medical and life insurance for the duration of the leave; (ii) to pay the
bonus, if any, that Tholen would 

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be entitled to under the terms of the bonus plans referred to in Section 4B of
this Agreement; and (iii) to allow Tholen to continue receiving benefits under
the disability insurance and other employee benefit plans in effect at the time
of his disability in accordance with the terms and conditions of such plans. The
granting of a leave of absence does not guarantee that Tholen will be returned
to employment, and the Company reserves the right to replace Tholen or to take
other action in his absence due to business necessity. If Tholen is certified to
return to work before his leave of absence expires, and desires to do so, the
following provisions shall apply: (i) the Company will attempt to return Tholen
to his same or similar position, provided this does not result in undue hardship
to the Company; and (ii) if the Company is unable to reinstate Tholen because
his position has been filled, then as a special severance benefit, the Company
shall pay a lump-sum severance payment equal to twelve (12) months of Tholen's
base salary as in effect immediately prior to the commencement of Tholen's leave
of absence. If Tholen is not certified to return to work before his leave of
absence expires, or does not desire to return, his employment and this Agreement
shall terminate upon the expiration of his leave of absence.

                    c. Termination For Cause: The Company may terminate this
Agreement for cause immediately upon written notice to Tholen in the event
Tholen (i) in the course of his duties engages in misconduct which has a
material adverse effect on the Company or its business, willfully breaches this
Agreement in any material respect or consistently or habitually neglects his
duties as a Company officer, or (ii) is finally convicted of a felony. In either
event, the Company's sole obligation to Tholen in lieu of all claims for
compensation or damages shall be to pay all compensation owing for services
rendered by Tholen prior to the date of termination under this subsection.

                    d. Termination Without Cause: The Company in its sole
discretion may terminate this Agreement without cause or prior warning
immediately upon written notice to Tholen. For purposes of this Section 5D, any
resignation following a substantial reduction in Tholen's salary, benefits
(including the failure of Company to include Tholen as a participant in its
executive or management bonus plans), duties or responsibilities shall
constitute an involuntary termination without cause. In the event of a
termination under this Section 5D, the Company shall pay all compensation owing
for services rendered by Tholen prior to the date of termination, shall pay a
lump-sum severance benefit equal to (i) the number of months remaining of the
term of this Agreement or (ii) twelve (12) months, whichever is less, of
Tholen's base salary at the time of termination, and shall continue to provide
Tholen at Company expense all medical, disability and insurance benefits
available to him at the time of termination for the same number of months as
used to calculate the lump-sum severance benefit. As an additional severance
payment, if the Company has in effect at the time of any termination without
cause under this Section 5D any bonus or incentive plan which provides for
awards in cash and is based on the Company's revenues or results of operations
for a fiscal year, Tholen shall be entitled to an amount equal to a pro rata
award based on the period of the fiscal year for which he was employed if a
termination under this Section 5D occurs after the completion of three fiscal
quarters. Such severance shall be payable at the same time, and computed on the
same terms, as 

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awards under the plan in question, except for periods of service. Such payments
and benefits shall not entitle Tholen to any other benefits or compensation
program available to Company employees.

                    e. Termination Following Change In Control: If either the
Company elects to terminate Tholen without cause pursuant to Section 5D within
ninety (90) days before or twenty four (24) months after a change in control or
Tholen elects to resign with good reason within twenty four (24) months after a
change in control of the Company, then as a severance benefit and in lieu of all
compensation or damages the Company shall (i) pay Tholen a lump sum equal to
200% of the average of the annual base salary plus bonuses paid to Tholen during
each year of service with the Company prior to the time of such termination or
resignation (or if Tholen has been employed for less than three (3) years at
such time, 200% of the average annual salary plus bonus paid during the term of
employment, assuming for any uncompleted year that a bonus at least equal to the
prior year bonus would be paid); (ii) continue to provide Tholen at Company
expense all medical, disability and insurance benefits available to him at the
time of such termination or resignation for a period of twenty four (24) months
after such termination or resignation, or, if shorter, the maximum period
allowed under the Company's policies as then in effect or under applicable law,
(iii) accelerate the vesting of all unvested stock options granted to Tholen
under the Company's stock option or other benefit plans so that all such stock
options will vest and be fully exercisable on the date of such termination or
resignation, and (iv) extend the post-termination exercise period for all stock
options granted to Tholen under the Company's stock option and other benefit
plans so that all such stock options will be exercisable for a period of three
months after the date of such termination or resignation (except that with
respect to any stock options having a post-termination exercise period in excess
of three months, such longer post-termination exercise period shall remain in
effect).

                         For purposes of this subsection, the term "change in
control" shall mean any change in control that the Company would be required to
report in response to Item 5(f) of Schedule 14A of Regulation 14A promulgated
under the Securities Exchange Act of 1934, as amended (the "Exchange Act").
Without limiting the foregoing, a change in control shall also be deemed to have
occurred if (i) any "person" as defined in Section 13(d) and 14(d) of the
Exchange Act is or becomes, directly or indirectly, the "beneficial owner" as
defined in Rule 13 (d-3) under the Exchange Act of securities of the Company
which represent 25% or more of the combined voting power of the Company's then
outstanding securities; or (ii) during any period of two consecutive years,
individuals who at the beginning of said two year period constituted the Board
of Directors of the Company cease for any reason to constitute at least a
majority of the Board unless the election or nomination of each new director was
approved by a vote of at least two-thirds of the directors who were in office at
the beginning of said two year period.

                         For purposes of this subsection, Tholen shall be deemed
to have resigned "with good reason" if he does so following a change in control
as a 

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result of the Company having done any or all of the following without Tholen's
express written consent: (i) assigned Tholen different duties or made changes in
his reporting responsibilities, title, or office that are substantially
inconsistent with Tholen's duties, responsibilities, titles, or offices
immediately prior to the change in control; (ii) reduced Tholen's base salary
from that in effect at the time of the change in control; (iii) failed to
continue any bonus plan in substantially the same form as it existed prior to
the change in control; (iv) required Tholen to be based more than fifty (50)
miles from his present office location, except for required travel consistent
with Tholen's present business travel obligations; (v) failed to continue any
plan or program for compensation, employee benefits, stock purchase or
ownership, life insurance, group medical, disability, or vacation in
substantially the same form as immediately prior to the change in control, or
otherwise made any material reduction in Tholen's fringe benefits, or (vi)
failed to obtain the assumption of this Agreement by any successor to the
Company.

                         Tholen shall not be entitled to the benefits of this
Section 5(E) if this Agreement and his employment are terminated pursuant to
Section 5(A), (B) or (C).

                    f. Company's Obligations Under This Agreement Exclusive: The
benefits set forth in subsections A through E above (which benefits, in the
event of termination pursuant to subsections A, C, D or E, include payment for
services rendered prior to termination as provided in such subsections), as
applicable, constitute the sole obligations of the Company to Tholen upon a
termination and are in lieu of any damages or other compensation that Tholen may
claim under other Company policies in connection with this Agreement. The
benefits on termination in this Agreement are in substitution for any severance
or termination benefits otherwise available under Company policies of general
application. Tholen expressly acknowledges that certain Company benefit or
incentive plans provide for vesting in, or award of, benefits based on
employment on or through particular dates and that nothing in this Agreement
entitles him to partial vesting or partial awards under such plans. Any payments
under Section 5D relating to any incentive or bonus plan are expressly
acknowledged to be benefits under this Agreement and not an interpretation or
modification of any such plan.

                    g. Resignation As Officer: In the event of any termination
pursuant to this Section 5, Tholen shall be deemed to have resigned as an
officer of the Company if he was serving in such capacity at the time of
termination.

               6. Confidentiality: Tholen acknowledges and agrees that he has
been and will continue to be entrusted with certain trade and proprietary
information regarding the products, processes, methods of manufacture and
delivery, know-how, designs, formula, work in progress, research and
development, computer software and data bases, copyrights, trademarks, patents,
marketing techniques, and future business plans, as well as customer lists and
information concerning the identity, needs, and desires of actual and potential
customers of the Company and its subsidiaries, joint 

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venturers, partners, and other affiliated persons and entities, all of which
derive significant economic value from not being generally known to others
outside the Company ("Confidential Information").

                    a. During the entire term of his employment with the Company
and for two years thereafter, Tholen shall not disclose or exploit any
Confidential Information except for the sole benefit of the Company or with its
express written consent.

                    b. During the entire term of his employment by the Company
and for one year thereafter, Tholen shall not directly or indirectly solicit any
person or company known by Tholen to be an actual or actively sought customer of
the Company or its subsidiary and affiliated companies for any business is known
by Tholen to be conducted or under development by the Company, except for the
sole benefit of the Company or with its express written consent.

                    c. During the entire term of his employment by the Company
and for one year thereafter, Tholen shall not induce or attempt to induce any
employee of the Company to leave the Company's employ except for the sole
benefit of the Company or with its express written consent.

                    d. In the event any provision in this Section 6 is more
restrictive than allowed by the law of any jurisdiction in which the Company
seeks enforcement, such provision shall be deemed amended and shall then be
fully enforceable to the extent permitted by such law.

                    e. Tholen acknowledges and agrees that any violation of this
Section 6 would cause immediate irreparable damage to the Company, and that it
would be extremely difficult or impossible to determine the amount of damage
caused to the Company. Tholen therefore agrees that the Company's remedies at
law are inadequate, and hereby consents to issuance of a temporary restraining
order, preliminary and permanent injunction, and other appropriate relief to
restrain any actual or threatened violation of this Section, without limiting
any remedies the Company may have at law or in equity.

               7. Inventions: Any and all patents, copyrights, trademarks,
inventions, discoveries, developments, or trade secrets developed or perfected
by Tholen during or as the result of his employment with the Company shall
constitute the sole and exclusive property of the Company. Tholen shall disclose
all such matters to the Company, assign all right, title and interest he may
have in them, and cooperate with the Company in obtaining and perfecting any
patent, copyright, trademark, or other legal protection. This Section 7 shall
not apply to any invention which qualifies fully under California Labor Code
Section 2870, a true copy of which is attached to this Agreement as Exhibit A.

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               8. Conflict Of Interest: During the term of this Agreement,
Tholen shall devote his time, ability, and attention to the business of the
Company, and shall not accept other employment or engage in any other outside
business activity which interferes with the performance of his duties and
responsibilities under this Agreement or which involves actual or potential
competition with the business of the Company, except with the express written
consent of the President.

               9. Employee Benefit Plans: All of the employee benefit plans
referred to or contemplated by this Agreement shall be governed solely by the
terms of the underlying plan documents and by applicable law. Nothing in this
Agreement shall impair the Company's right to amend, modify, replace and
terminate any and all such plans in its sole discretion as provided by law, or
to terminate this Agreement in accordance with its terms. This Agreement is for
the sole benefit of Tholen and the Company, and is not intended to create an
employee benefit plan or to modify the term of existing plans.

               10. Parachute Limitation: The payments and benefits Tholen is
entitled to under this Agreement and all other contracts, arrangements, or
programs shall not, in the aggregate, exceed the maximum amount that may be paid
to Tholen without triggering golden parachute penalties under Section 280G and
related provisions of the Internal Revenue Code, as determined in good faith by
the Company's independent auditors. If Tholen's benefits must be cut back to
avoid triggering such penalties, Tholen's benefits shall be cut back in the
priority order designated by Tholen or, if Tholen fails promptly to designate an
order, in the priority order designated by the Company. If an amount in excess
of the limit set forth in this Section is paid to Tholen, Tholen must repay the
excess amount to the Company upon demand, with interest at the rate provided for
in Internal Revenue Code Section 1274(b)(2)(B). Tholen and the Company agree
reasonably to cooperate with each other in connection with any administrative or
judicial proceedings concerning the existence or amount of golden parachute
penalties with respect to payments or benefits Tholen receives. No part of this
Agreement is made in contemplation of, or anticipates any presently impending
change in, ownership or control. Further, no payment to be made to Tholen in
accordance with any provision of this Agreement, except Paragraph 4E entitled
"Termination Following Change in Control", is contingent upon a change in
ownership or control of the Company. This Agreement does not provide for
payments to Tholen which are significantly different in amount, timing, terms,
or conditions from those provided under contracts entered into by the Company
and individuals performing comparable services.

               11. Assignment: This Agreement may not be assigned by Tholen, but
may be assigned by the Company to any successor in interest to its business. In
the event the Company does not survive any merger, acquisition, or other
reorganization, it shall make a reasonable effort to obtain an assumption of
this Agreement by the surviving entity in such merger, acquisition, or other
reorganization, but the failure to obtain such assumption shall not prevent or
delay such merger, acquisition, or other reorganization or relieve the Company
of its other obligations under this Agreement. 

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This Agreement shall bind and inure to the benefit of the Company's successors
and assigns, as well as Tholen's heirs, executors, administrators, and legal
representatives.

               12. Notices: All notices required by this Agreement may be
delivered by first class mail at the following addresses:

                  To the Company:   Hycor Biomedical Inc.
                                    7272 Chapman Avenue
                                    Garden Grove, CA 92814-2103

                  To Tholen:        J. David Tholen
                                    2080 Spalding Drive
                                    Atlanta, GA 30350

               13. Amendment. This Agreement may be modified only by written
agreement signed by the party against whom any amendment is to be enforced.

               14. Choice Of Law: This Agreement shall be governed by the laws
of the State of California.

               15. Partial Invalidity: In the event any provision of this
Agreement is void or unenforceable, the remaining provisions shall continue in
full force and effect.

               16. Waiver: No waiver of any breach of this Agreement shall
constitute a waiver of any subsequent breach.


                                            "Company"

                                            HYCOR BIOMEDICAL INC.


Dated:  December 27, 1998                   By:    /s/ Samuel D. Anderson
                                                   ----------------------
                                            Name:  Samuel D. Anderson
                                            Title: Chairman of the Board

                                            "Tholen"

                                            J. DAVID THOLEN

Dated:  January 4, 1999                     /s/ J. David Tholen
                                            ---------------------
                                            J. David Tholen
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                                    EXHIBIT A


                       CALIFORNIA LABOR CODE SECTION 2870

                   EMPLOYMENT AGREEMENTS; ASSIGNMENT OF RENTS


               (a) Any provision in an employment agreement which provides that
an employee shall assign, or offer to assign, any of his or her rights in an
invention to his or her employer shall not apply to an invention that the
employee developed entirely on his or her own time without using the employer's
equipment, supplies, facilities, or trade secret information except for those
inventions that either:

                    (1) Relate at the time of conception or reduction to
practice of the invention to the employer's business, or actual or demonstrably
anticipated research or development of the employer; or

                    (2) Result from any work performed by the employee for the
employer.

               (b) To the extent a provision in an employment agreement purports
to require an employee to assign an invention otherwise excluded from being
required to be assigned under subdivision (a), the provision is against the
public policy of this state and is unenforceable.