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                                                                   EXHIBIT 10.46

                  TRANSITION SERVICES AND FACILITIES AGREEMENT

         TRANSITION SERVICES AND FACILITIES AGREEMENT (this "Agreement") dated
as of March 3, 1997 by and between AccuMed International, Inc., a Delaware
corporation ("AccuMed"), and Difco Laboratories Incorporated, a Michigan
corporation ("Difco").

         WHEREAS, the execution and delivery of this Agreement is a condition
precedent to the consummation of the transactions contemplated by the Asset
Purchase Agreement (the "Asset Purchase Agreement") dated as of the date hereof
between AccuMed and Difco Microbiology Systems, Inc., a Michigan corporation
(the "Seller"),  (capitalized terms not otherwise defined herein shall have the
respective meanings set forth in the Asset Purchase Agreement);

         NOW, THEREFORE, in consideration of the premises and of the respective
representations, warranties, covenants, agreements and conditions contained
herein, and for other good and valuable consideration the receipt and
sufficiency of which are hereby acknowledged, and intending to be legally
bound, the parties hereto agree as follows:

         Section 1.       Usage.

                 1.1      References to Persons who are not parties hereto are
also references to its permitted assigns and permitted successors in interest
(by means of merger, consolidation or sale of all or substantially all the
assets of such Person or otherwise, as the case may be), and references to
Persons who are parties hereto are also references to its permitted assigns and
permitted successors in interest as provided in Section 11.

                 1.2      References to a document are to it as amended, waived
and otherwise modified as of the time in question and references to a statute
or other governmental rule are to it as amended and otherwise modified as of
the time in question (and references to any provision thereof shall include
references to any successor provision in effect as of the time in question).

                 1.3      References to Sections or to Schedules or Exhibits
are to sections hereof or schedules or exhibits hereto, unless the context
otherwise requires.

                 1.4      The definitions set forth herein are equally
applicable both to the singular and plural forms and the feminine, masculine
and neuter forms of the terms defined.





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                 1.5      The term "including" and correlative terms shall be
deemed to be followed by "without limitation" whether or not followed by such
words or words of like import.

                 1.6      The term "hereof" and similar terms refer to this
Agreement as a whole.

                 1.7      References to the "parties" are to Difco and AccuMed,
unless the context otherwise requires.

                 1.8      The date on which any notice or other writing is
deemed given shall be determined pursuant to Section 7.

         Section 2.       Use of Difco Transition Services.

                 2.1      Transitional Services.   Difco or, at Difco's
election, an Affiliate of Difco, shall use commercially reasonable efforts to
provide to AccuMed the transition services described on Schedule 2.1 during the
respective periods set forth thereon as AccuMed may reasonably request in
connection with the ESP Business.  Notwithstanding anything to the contrary set
forth in this Agreement, Difco's obligations to provide such transition
services shall in all cases be subject to the availability of qualified
employees to perform such services and Difco shall have no obligation to hire
or replace employees to provide such services unless Difco shall have
terminated the employment of employees who otherwise would have provided such
services.

                 2.2      Payment for Services.    AccuMed shall pay Difco
compensation for the services described in Section 2.1 in accordance with the
methods of calculation set forth on Schedule 2.1.  Payment shall be due within
30 days following the date on which the applicable invoice is deemed given.  If
payment in full is not received when due, AccuMed agrees to pay a 1% per month
service charge with respect to such unpaid amounts net of any amounts of
account receivable then in possession of Difco for the account of AccuMed.  All
payments under this Section 2, Section 3 or otherwise under this Agreement
shall be made by AccuMed in full without set off, counterclaim, defense or
other reduction whatsoever.

         Section 3.       Lease of R&D Facilities; Use of Common Areas.

                 3.1      Lease of R&D Facilities.

                          (i)     The "AccuMed Space" means, collectively, each
of the areas described on Schedule 3.1 as the AccuMed Space, which is located at
the facilities located on the first floor of the building at 1180 Ellsworth
Road, Ann Arbor, Michigan 48108 (the "R&D Facility").  The "Common Areas"
means, collectively, each of





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the areas described on Schedule 3.1 as Common Space, which is located at the R&D
Facility.

                          (ii)   Difco hereby leases to AccuMed and AccuMed
hires from Difco on the terms and conditions set forth herein (the "Lease"),
the following rights, (1) exclusive (subject to the further terms and
conditions hereof) use and enjoyment of the AccuMed Space, and (2)
non-exclusive use and enjoyment of the Common Areas.  The initial term of the
Lease shall commence on the date hereof and shall continue until the six month
anniversary of the date hereof or earlier termination in accordance with
Section 5 of this Agreement and shall continue thereafter until either party
shall give notice of termination on not less than 90 days, prior written notice
(which could include a termination effective as of the six month anniversary of
the date hereof (the "Lease Term").

                          (iii) In consideration of the Lease, AccuMed shall
pay to Difco $10,084 (the "Lease Payments") on the first day of each month
during the term of this Agreement, which amount shall be deemed to include all
payments for electricity and other utilities used by AccuMed but shall not
include telecommunications services (including telephone and facsimile).
AccuMed shall arrange and pay for telecommunications services as it deems
necessary or appropriate.  A pro rated Lease Payment shall be made on the date
hereof with respect to the month in which this Agreement is executed and
delivered.

                 3.2      Title to R&D Facility; Right to Lease; Quiet
Enjoyment.  Difco represents to AccuMed that Difco is the fee owner of the R&D
Facility and has full power and lawful authority to grant the Lease and the
rights hereunder.  Difco further covenants and warrants that during the Lease
Term and as long as AccuMed is not in default beyond any applicable notice or
cure period under the terms of this Lease, AccuMed shall have quiet and
peaceful possession of the AccuMed Space and quiet and peaceful shared
possession of the Common Areas and shall enjoy all of the rights herein granted
without interference by Difco or any of its Affiliates.   Difco further
represents that there are no tenants in the R&D Facility on the date hereof
other than AccuMed.

                 3.3        The Common Areas shall at all times be subject to
the exclusive control and management of Difco and shall further be subject to
such rules and regulations reasonably adopted by Difco from time to time;
provided that AccuMed shall receive written notice thereof. Difco reserves the
right to make changes, additions, alterations, and improvements in and to the
Common Areas, provided that there shall be no unreasonable obstruction of
AccuMed's right of access to the AccuMed Space and no material impairment of
AccuMed's use of the Common Areas.





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                 3.4      The AccuMed Space during the continuance of the Lease
will be used and occupied solely for the conduct of the ESP Business (as
modified, expanded or otherwise adapted and developed by AccuMed from time to
time).  AccuMed agrees that (i) its use of the AccuMed Space (including the
conduct of the ESP Business therein) will comply in all material respects with
the laws or ordinances of the United States, the State of Michigan or the
municipality in which the AccuMed Space is located, and (ii) AccuMed will not
permit any Person to use the AccuMed Space or any part thereof for any use or
purpose in violation of such laws and ordinances.  AccuMed shall not use the
AccuMed Space in any manner which would cause an increase in fire and extended
coverage insurance premiums for the R&D Facility.  Difco makes no
representations or warranties as to any governmental zoning, licenses or
permits which may be required for the conduct of AccuMed's business permitted
in the AccuMed Space.

                 3.5      AccuMed shall not cause any Hazardous Substance (as
defined below) to be used, stored, generated or disposed of on or in the R&D
Facility by AccuMed's or AccuMed's agents, employees, contractors or invitees,
without first obtaining Difco's written consent, such consent not to be
unreasonably withheld.  If AccuMed uses, stores, generates or disposes of any
Hazardous Substances in the R&D Facility except as permitted above, or if the
R&D Facility becomes contaminated (excepting preexisting Hazardous Substances
or contamination, if any) in manner by AccuMed, AccuMed's agents, employees,
contractors or invitees, AccuMed shall indemnify and hold harmless Difco from
any and all claims, damages, fines, judgments, penalties, costs, liabilities or
losses (including, without limitation, a decrease in value of the R&D Facility,
damages due to loss or restriction of usable space, or any damages due to
adverse impact on marketing of the space, and any and all sums paid for
settlement of claims, and reasonable, documented attorneys' fees, consultant
and expert fees) arising during or after the Lease Term and arising as a result
of such contamination.  This indemnification includes, without limitation, any
and all costs incurred due to any investigation of the site or any cleanup,
removal or restoration mandated by a federal, state or local governmental
agency or political subdivision.  Without limitation of the foregoing, if
AccuMed causes the presence of any Hazardous Substance on the R&D Facility and
such results in contamination, AccuMed shall promptly, at its sole expense,
take any and all reasonable actions to return the R&D Facility to the condition
existing prior to the presence of any such Hazardous Substance on the R&D
Facility.  AccuMed shall first obtain Difco's approval for any such remedial
action, which approval shall not be unreasonably withheld.  "Hazardous
Substance" means any substance which is toxic, ignitable, reactive, corrosive,
or infectious materials and which is regulated by any local government having
jurisdiction over the R&D Facility, the State of Michigan, or the United States





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government.  "Hazardous Substance" includes any and all material or substances
which are defined as "hazardous waste", "extremely hazardous waste" or a
"hazardous substance" pursuant to state, federal or local governmental law,
including, but not limited to, the Michigan Medical Waste Regulatory Act, as
amended, the Federal Medical Waste Tracking Act of 1988, as amended, and the
Michigan Public Health Code, as amended.  "Hazardous Substance" includes, but
is not restricted to, asbestos, polychlorobiphenyls ("PCB's") and petroleum.
Under no circumstances shall AccuMed be in any way liable for or responsible
for Hazardous Substances or contamination if such Hazardous Substances or
contamination were not brought, introduced, used or handled or otherwise placed
in the AccuMed Space, the Common Areas or the R&D Facility by AccuMed or its
agents, employees, contractors or invitees.

                 3.6      (i)  AccuMed shall maintain and keep in full force
and effect during the term of the Lease, general liability insurance, including
blanket contractual coverage in the amount of $5,000,000 for personal injury or
death resulting from one occurrence in the AccuMed Space and exterior and other
Common Areas and the sum of $1,000,000 for property damage resulting from any
one occurrence in the AccuMed Space and exterior or other Common Areas.
AccuMed shall deliver to Difco a certificate evidencing such coverage and
naming Difco as an additional insured.  Such insurance policy shall provide
that no cancellation shall be effective without at least 30 days' prior written
notice to Difco.

                 (ii)  At all times during the Lease Term, AccuMed will carry
and maintain, at AccuMed's expense, fire and extended coverage insurance
covering all leasehold improvements in the AccuMed Space and all of Difco's
equipment, trade fixtures, appliances, furniture, furnishings and personal
property from time to time in, on or upon the AccuMed Space and insurance
covering all plate glass located from time to time in, on or upon the AccuMed
Space.  This insurance will be in an amount not less than the full replacement
cost without deduction for depreciation.  This insurance will provide
protection against all perils included within the classification of fire,
extended coverage, vandalism, malicious mischief, special extended peril
(all-risk), boiler, flood and sprinkler leakage.

                 (iii)  In the event of loss under any policy or policies
provided by AccuMed to Difco under this Section 3.6, other than the liability
policy, the insurance proceeds will be payable to Difco; thereafter, such
proceeds, with the exception of the loss of rents insurance proceeds, will, be
used for the expense of repairing or rebuilding the improvements which have
been damaged or destroyed if Difco is reasonably satisfied that the amount of
insurance proceeds are and will be at all times sufficient to pay for the
completion of the repairs or rebuilding, and, if not in such manner as Difco





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deems appropriate; provided that, if Difco elects not to repair or rebuild such
improvements, AccuMed shall have the right to terminate this Lease immediately
without further obligation to Difco.

                 (iv)  AccuMed hereby waives any and all rights of recovery
against Difco for any loss or damage caused by fire or any of the risks covered
by standard fire and extended coverage, vandalism and malicious mischief
insurance policies.

                 (v)  If AccuMed fails to provide all or any of the insurance
required to be provided by it pursuant to this Section 3.6, Difco may (but
shall not be required to) procure or renew such insurance, and any amounts paid
for such insurance shall be reimbursed by AccuMed within 15 business days
following the date on which demand therefor is deemed given to AccuMed by
Difco.

                 3.7      (i)  AccuMed agrees at its own expense to keep the
AccuMed Space including all structural, electrical, mechanical and plumbing
systems that service the AccuMed Space only, at all times in good order and
repair (including any necessary replacements made necessary by the acts or
omissions of AccuMed) except for normal wear and tear, unless the need for
repairs is caused by the gross negligent acts or omissions of Difco.  Difco
shall maintain and keep in good repair the roof and outer walls of the R&D
Facility as well as structural, electrical, mechanical and plumbing systems
that service the Common Areas or the entire R&D Facility, unless the need for
repairs is caused by the acts or omissions of AccuMed.

                 (ii)  Notwithstanding any other provision of the Lease, from
and after the date AccuMed takes occupancy of the AccuMed Space, any repairs,
additions or alterations to the AccuMed Space or any of its systems that
service the AccuMed Space only (e.g., plumbing, electrical, mechanical)
structural or non-structural, which are required by any law, statute,
ordinance, rule, regulation or governmental authority or insurance carrier,
including, without limitation, OSHA, will be the obligation of AccuMed
(provided that any such repairs, additions or alterations must be approved by
Difco in advance and, if requested by Difco, shall be performed by such
contractors as Difco shall approve with all costs and expense paid by AccuMed).
Difco, at its cost and expense, shall be responsible for any non-conformance
existing prior to the date AccuMed takes occupancy of the AccuMed Space.

                 (iii)  AccuMed acknowledges that it has examined the AccuMed
Space prior to the making of this Lease, that no representations or warranties
as to the condition or the state of repairs thereof have been made by Difco
which are not expressly set forth herein, and that AccuMed hereby accepts the
AccuMed Space in its present condition at the date of this Agreement.





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                 3.8      The parties agree that AccuMed will not make any
alterations, additions, or improvements to the AccuMed Space without the
written consent of Difco, which consent shall not be unreasonably withheld or
delayed.  All alterations, additions or improvements made by either of the
parties hereto on the AccuMed Space will be the property of Difco and will
remain on and be surrendered with the AccuMed Space at the termination of the
Lease, except that alterations, additions or improvements made by AccuMed must
be removed and the AccuMed Space restored by AccuMed if so requested by Difco.

                 3.9      AccuMed will keep the AccuMed Space free of liens of
any sort and will hold Difco harmless from any liens which may be placed on the
AccuMed Space except those attributable to the acts of Difco.

                 3.10     AccuMed agrees to permit Difco and the authorized
representatives of Difco to enter the AccuMed Space at all reasonable times
upon reasonable prior notice for the purpose of inspecting the same, and
further agrees that Difco and its authorized representatives shall have the
right to enter the AccuMed Space at any time in the event of an emergency.

                 3.11     At the expiration (or earlier termination) of the
Lease Term, AccuMed will surrender the AccuMed Space broom clean and free of
all contaminants (viral, bacterial and others) and Hazardous Substance if the
same were brought, introduced, used, handled or otherwise placed in the AccuMed
Space, the Common areas or R&D Facility by AccuMed or its agents, employees,
contractors or invitees and in as good condition and repair as it was at the
time AccuMed took possession, reasonable wear and tear excepted, and promptly
upon surrender will deliver all keys and building security cards for the R&D
Facility to Difco at the place then fixed for payment of Lease Payments.  All
costs and expenses incurred by Difco in connection with repairing or restoring
the AccuMed Space to the condition in which it was received from Difco together
with the costs, if any, of removing from the AccuMed Space any property of
AccuMed left therein, shall be invoiced to AccuMed and shall be payable as
additional rent within 15 business days after the related invoice is deemed
given.

                 3.12      AccuMed at its expense will pay, defend, fully
indemnify and save Difco and the Difco Related Parties, harmless from any Loss
(as hereinafter defined) to or for any Person or property, whether based on
contract, tort, negligence or otherwise, arising directly or indirectly out of
or in connection with the condition of the AccuMed Space, the use or misuse
thereof by AccuMed or any other Person, the acts or omissions of AccuMed, its
licensees, servants, agents, employees or contractors or invitees, the failure
of AccuMed to comply with any provision of this





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Agreement, or any event on the AccuMed Space, whatever the cause; provided,
however, that nothing herein shall be construed to require AccuMed to indemnify
against Difco's gross negligence or intentional misconduct.

         Section 4.       Confidentiality

                 4.1      Definitions.

                          (i)  "AccuMed's Technical Information" means all
material know-how, Trade Secrets, patents, processes, drawings, data,
specifications, formulas, recipes, test methods, or documentation setting forth
the design, assembly, tests or operation relating to intellectual property
assets, all for which AccuMed holds an ownership interest, including the
Purchased Assets.

                          (ii) "Difco's Technical Information" means all
material know-how, Trade Secrets, patents, processes, drawings, data,
specifications, formulas, recipes, test methods, or documentation setting forth
the design, assembly, tests or operation relating to intellectual property
assets, all for which DIFCO holds an ownership interest.

                          (iii) "Know-How" shall mean Technical Information
held in confidence by the owner of such Technical Information.

                          (iv)    "Trade Secrets" shall mean Technical
Information of value and secret, meaning the owner of such Technical
Information regards it as secret and has taken measures to prevent the
Technical Information from becoming available to Persons other than those
selected by the owner for a limited purpose, including marking tangible or
written forms thereof as of "Confidential-Trade Secret."

                 4.2      Obligations to Maintain Confidentiality.  AccuMed and
Difco each agree that the Know-How and/or Trade Secrets owned by the other
party is confidential, and in that regard each agree to:

                          (i) exercise its best efforts not to acquire, come
into possession of, or assimilate the other's Know-How and/or Trade Secrets in
any manner not in accordance with the terms of this Agreement;

                          (ii) exercise the same degree of care it uses for its
own confidential information to avoid publishing or otherwise revealing the
other's Know-How and/or Trade Secrets to third





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parties without the prior express written permission of the party who owns the
Know-How and/or Trade Secrets to be revealed;

                          (iii) treat the other's Know-How and/or Trade Secrets
in accordance with the highest standards used by it for its own most sensitive
information, whether such Know-How is acquired inadvertently or pursuant to or
in violation of the terms of this Agreement;

                          (iv) disclose or make available the other's Know-How
and/or Trade Secrets only to employees on a so-called "need-to-know" basis,
and only to the extent required to permit each party the full benefits of the
terms and provisions hereof;

                          (v) to the extent reasonably practicable,
appropriately identify and mark all reproductions, copies, extracts or the like
of any documents containing the other's Know-How and/or Trade Secrets as the
"Property of" such other party and as "Confidential," or "Confidential Trade
Secret", as the case may be, before distributing the same to its officers,
employees, or, if expressly permitted hereunder, to others; and

                          (vi) notify the other party immediately upon receipt
of any demand or request by a court or other governmental body for access to or
disclosure of any Know-How and/or Trade Secrets owned by the other party, and
shall take all steps and actions reasonably necessary to prevent such
disclosure and shall cooperate with and support the actions of the other, at
the other's expense, to appear and object to such request or demand for access
or disclosure.

                 4.3  Relief of Obligations.  Each party shall be relieved of
its obligations in Section 4.2, to the extent that such party is compelled to
disclose by judicial or administrative process or by other requirements of law,
(provided that it has given notice thereof to the other as soon as
practicable), and to the extent that such information can be shown to have been
(i) in the public domain through no fault of such party or any Affiliate
thereof, (ii) later lawfully acquired by Difco or any such Affiliate, as the
case may be, from a third-party, or (iii) or independently developed by such
third-party as of the date such third-party acquires, or is acquired by, Difco
or any of its Affiliates.  Each party shall also be relieved of its obligation
pursuant to Section 4.2 to the extent that such party and any such Affiliate
may disclose such information to their respective officers, directors,
employees, accountants, counsel, consultants, advisors and agents in connection
with the transactions contemplated by this Agreement





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so long as such Persons are informed by such Party or such Affiliate, as the
case may be, of the confidential nature of such information and are directed by
such party or such Affiliate, as the case may be, to treat such information
confidentially.  The obligation of a party and its Affiliates to hold any such
information in confidence shall be satisfied if they exercise the same care with
respect to such information as they would take to preserve the confidentiality
of their own similar information.

                 4.4      Injunctive Relief.  Each of the parties acknowledges
that in the event of a breach by any of them of any provision of this Section
4, the aggrieved party may be without an adequate remedy at law.  Each of the
parties therefore agrees that in the event of such a breach hereof the
aggrieved party may elect to institute and prosecute proceedings in any court
of competent  jurisdiction to enforce specific performance or to enjoin the
continuing breach hereof.  By seeking or obtaining any such relief, the
aggrieved party will not be precluded from seeking or obtaining any other
relief to which it may be entitled.  Notwithstanding Section 8, if an aggrieved
party seeks specific performance or any other extraordinary or provisional
relief including, but not limited to, injunctive relief pursuant to this
Section 4.4, then any such action shall not be subject to arbitration.   Each
of the parties agrees to submit to the non-exclusive jurisdiction of the
federal and/or state court located in the State of Michigan and waives any and
all objections to jurisdiction and venue that it may have under the laws or
court rules of any state, the United States or court.

                 4.5      Employee Confidentiality Agreements.  Difco agrees,
except in an emergency, to use reasonable efforts (without, however, any
obligation to provide any special compensation or benefits) to obtain from each
officer and employee having access to the AccuMed Trade Secrets, Know How and
any other confidential and non-public information an agreement substantially in
the form of Exhibit A whereby such Person agrees to hold in confidence any such
information of AccuMed or any of its Affiliates of which such Person becomes
aware while in the R&D Facility or performing services hereunder or otherwise.
AccuMed agrees to use reasonable efforts (without, however, any obligation to
provide any special compensation or benefits) to obtain, except in the case of
an emergency, from each officer and employee), having access to the AccuMed
Space and/or Common Areas, an agreement substantially in the form of Exhibit A
whereby such Person agrees to hold in confidence any Know-How, Trade Secrets
and other confidential non-public information of Difco or any of its Affiliates
of which such





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Person becomes aware while in the R&D Facility or otherwise.  Each of AccuMed
and Difco agrees to use reasonable efforts to maintain a permanent list
identifying all such Persons having access to the Know-How of the other party,
which list, together with the signed agreements, shall be available upon
reasonable notice.

                 4.6      Return of Know-How.  Upon termination of this
Agreement, each party agrees to return all Know-How and/or Trade Secrets owned
by the other party, including any reproductions, copies and extracts or the
like, or an officer of the party in possession shall certify in writing as to
their destruction.

                 4.7      Continuing Obligations.

                 (i)  Difco's obligations pursuant to Section 4.2 shall
continue for a period of two years beyond the term of this Agreement.

                 (ii)  AccuMed's obligations pursuant to Section 4.2 shall
continue for a period of two years beyond the term of this Agreement.

         Section 5.  Term; Renewal; Termination.

                 5.1      Term.  The term of this Agreement shall be 6 months
from the date hereof, unless earlier terminated in accordance with the terms
hereof.

                 5.2      Termination.  Anything contained in this Agreement to
the contrary notwithstanding, this Agreement may be terminated at any time:

                          (i)     by the mutual written consent of AccuMed and
Difco;

                          (ii)    by AccuMed in the event of any material
breach by Difco of any of Difco's agreements, representations, warranties or
covenants contained herein and the failure of Difco to cure such breach within
30 days after the date on which notice from AccuMed requesting such breach to
be cured is deemed delivered;

                          (iii) by Difco in the event of any material breach by
AccuMed of any of AccuMed's agreements, representations,





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warranties or covenants contained herein and the failure of AccuMed to cure
such breach within 30 days after the date on which notice from Difco requesting
such breach to be cured is deemed delivered; or

                          (vi) by Difco or AccuMed in the event that any
petition in bankruptcy is filed by or against the other and remains undismissed
for 60 days, provided that if applicable law allows the trustee in bankruptcy
or such party to affirm this Agreement and perform the other party's
obligations hereunder, then said trustee or such other party shall cure all
outstanding defaults within the period determined by the bankruptcy court and
provide such other party such adequate assurances as may be necessary to ensure
the other party's continued performance under this Agreement.

         Section 6. Governing Law.  THIS AGREEMENT SHALL BE GOVERNED BY
AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF MICHIGAN, WITHOUT GIVING REGARD TO
THE CONFLICT OF LAWS PRINCIPLES THEREOF.

         Section 7.  Notices.  All notices given pursuant to this Agreement
shall be in writing and shall be made by hand-delivery, first-class mail
(registered or certified, return receipt requested), telex, telecopier, or
overnight air courier guaranteeing next business day delivery to the relevant
address specified below.  Except as otherwise provided in this Agreement, each
such notice shall be deemed given: at the time delivered by hand, if personally
delivered or mailed; when answered back, if telexed; when receipt is
acknowledged, if telecopied; and the next business day after timely delivery to
the courier, if sent by overnight air courier guaranteeing next business day
delivery.

                 If to AccuMed, to:

                 AccuMed International, Inc.
                 900 North Franklin Street, Suite 401
                 Chicago, Illinois 60610
                 Attention:  Mr. Peter P. Gombrich
                             Chief Executive Officer

                 Telecopy No.: (312) 642-3101
                 Confirmation No.: (312) 642-9200

                 with a copy to:





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                 AccuMed International, Inc.
                 1500 - 7th Avenue
                 Sacramento, California
                 Attention:  Ms. Joyce Wallach
                             General Counsel

                 Telecopy No.:  (916) 443-6850
                 Confirmation No.:  (916) 443-6800

                 If to Difco, to:

                 Difco Laboratories Incorporated
                 17197 N. Laurel Park, Suite 400
                 Livonia, Michigan 48152
                 Attention:  Mr. Kenneth A. Lawton
                             Executive Vice President Finance and Operations


                 Telecopy No.: (313) 462-8528
                 Confirmation No.: (313) 462-8562

                 with a copy to:

                 Miller, Canfield, Paddock and Stone, P.L.C.
                 1400 North Woodward Avenue
                 Bloomfield Hills, Michigan 48304
                 Attention:  Mr. Thomas G. Appleman

                 Telecopy No.: (810) 258-3036
                 Confirmation No.: (810) 258-3009

or to such other address as such party may indicate by a notice delivered to
the other party hereto.

         Section 8.  Arbitration.  Difco and AccuMed agree that any
claim, controversy or dispute arising out of or relating to this Agreement,
except as otherwise provided in Section 4.4, the interpretation of any of the
provisions hereof and thereof, or the





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action or inaction of any party shall be submitted to neutral, binding
arbitration in accordance with the Commercial Arbitration Rules of the American
Arbitration Association (or any successor thereto) and the Federal Arbitration
Act, 9 U.S.C.A. sections 1-14 shall apply. Any award or decision obtained from
any such arbitration proceeding shall be final and binding on the parties, and
judgment upon any award thus obtained may be entered in any court having
jurisdiction thereof.  Any such arbitration shall be conducted in Livonia,
Michigan (or such other location in the State of Michigan as the Parties shall
agree).

         Section 9.  Exculpation and Indemnification.  None of Difco 
nor any of its officers, directors, employees, agents, invitees, affiliates, 
successors or assigns (the "Difco Related Parties") shall be liable
to AccuMed or any of its officers, directors, employees, agents, invitees,
affiliates, successors or assigns (the "AccuMed Related Parties") with respect
to any losses, costs, liabilities, settlement payments, awards, judgments,
fines, penalties, damages (including compensatory, consequential, incidental,
special, punitive and exemplary), expenses, or other charges (including
reasonable attorney's fees) ("Losses"),  and AccuMed (on behalf of itself and
the AccuMed Related Parties) hereby waives and agrees to not make any claim
against any of Difco or the Difco Related Parties therefor, and to pay, fully
indemnify, defend and hold harmless Difco and the Difco Related Parties from
any such Losses resulting from, arising out of or related to the performance of
any of the services provided or required to be provided by Difco under this
Agreement, except only for Losses arising out of the gross negligence or
willful misconduct of Difco. AccuMed and, subject to the foregoing,  Difco
shall pay, fully indemnify, defend and hold each other harmless with respect to
any Losses (but excluding any consequential, incidental, special, punitive and
exemplary damages) arising out of either party's violation of, or failure to
comply with, any material provision of this Agreement and, in addition, AccuMed
shall pay, fully indemnify and hold Difco and the Difco Related Parties
harmless from any Losses arising out of any claims made by AccuMed employees
housed in the AccuMed Space except for Losses arising out of the gross
negligence or willful misconduct of Difco.

         Section 10.  Successors and Assigns.  This Agreement shall be
binding upon and inure to the benefit of the parties hereto and their
successors and permitted assigns.  AccuMed may not assign this Agreement
without the written consent of Difco.  Difco may assign this Agreement to any
of its Affiliates or to any Person acquiring all or substantially all of its
assets provided that any such assignee shall first deliver to AccuMed an
agreement pursuant to which the assignee assumes all of Difco's obligations
under this





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<PAGE>   15


Agreement and agrees to be bound by all terms and conditions of this Agreement
and the assignor shall notwithstanding any such assignment remain liable for
all of its obligations hereunder.  Nothing in this Agreement, expressed or
implied, is intended or shall be construed to confer upon any Person other than
the parties and successors and assigns permitted by this Section 6 any right,
remedy or claim under or by reason of this Agreement, except that Section 3.12
and Section 9 shall also be for the benefit of, and enforceable by, the Difco
Related Parties.

         Section 11.  Entire Agreement.  This Agreement and the Exhibits and
Schedules hereto together with the Asset Purchase Agreement and the Ancillary
Agreements contain the entire understanding of the parties with regard to the
subject matter contained herein and therein, and supersede all prior agreements
and understandings between the parties including expressly the Offer Term Sheet
dated as of November 25, 1996 and except for the Confidentiality Agreement
dated November 8, 1996, as amended January 7, 1997, between AccuMed and Difco.
Any actions taken by Difco or its Affiliates under any of the Ancillary
Agreements shall not constitute a breach or default under this Agreement.

         Section 12.  Amendments.  This Agreement shall not be amended,
modified or supplemented except by a written instrument signed by an authorized
representative of each of the parties.

         Section 13.  Interpretation.  Section headings herein are inserted
for convenience of reference only and are not intended to be a part of or to
affect the meaning or interpretation of this Agreement.  The Schedules and
Exhibits hereto shall be construed with and as an integral part of this
Agreement to the same extent as if they were set forth verbatim herein.

         Section 14.  Waivers.  Any term or provision of this Agreement may
be waived, or the time for its performance may be extended, by the party or
parties entitled to the benefit thereof.  Any such waiver shall be validly and
sufficiently authorized for the purposes of this Agreement if, as to any party,
it is authorized in writing by an authorized representative of such party.  The
failure of any party to enforce at any time any provision of this Agreement
shall not be construed to be a waiver of such provision, nor in any way to
affect the validity of this Agreement or any part hereof or the right of any
party thereafter to enforce each and every such provision.  No waiver of any
breach of this Agreement shall be held to constitute a waiver of any other or
subsequent breach.

         Section 15.  Partial Invalidity.  Wherever possible, each
provision hereof shall be interpreted in such manner as to be effective and
valid under applicable law, but in case any one or more of the provisions
contained herein shall, for any reason, be held to be invalid, illegal or
unenforceable in any respect, such





                                       15
<PAGE>   16


provision shall be ineffective to the extent, but only to the extent, of such
invalidity, illegality or unenforceability without invalidating the remainder
of such invalid, illegal or unenforceable provision or provisions or any other
provisions hereof, unless such a construction would be unreasonable, in which
case the parties will negotiate in good faith to enter into appropriate
amendments hereto.

         Section 16.  Execution in Counterparts.  This Agreement may be
executed in one or more counterparts, each of which shall be considered an
original instrument, and all of which taken together shall constitute one and
the same agreement, and shall become binding when one or more counterparts have
been signed by each of the parties hereto and delivered to each of Difco and
AccuMed.

         Section 17.  Force Majeure.

                 (i)  If either party to this Agreement is totally or partially
prevented or delayed in the performance of any of its obligations under this
Agreement by force majeure and if such party gives written notice thereof to
the other party specifying the matters constituting force majeure together with
such evidence as it reasonably can give and specifying the period for which it
is estimated that such prevention or delay shall be excused from the
performance as from the date of such notice for so long as such cause or delay
shall continue.

                 (ii)  For the purpose of this Agreement, the term "force
majeure" shall be deemed to include any cause affecting the performance of this
Agreement arising from or attributable to acts, events, omissions or accidents
beyond the reasonable control of the party to perform and in particular but
without limiting the generality thereof shall include strikes, lock-outs or
other industrial action, civil commotion, riot, invasion, war, threat of or
preparation for war, fire, explosion, storm, flood, earthquake, subsidence,
epidemic or other natural physical disaster, impossibility of the use of
railways, shipping, aircraft, motor transport, or other means of public or
private transport, accidents, delays in providing materials (in each case other
than as a result of a breach or defaults by such Party or an Affiliate
thereof), shortages in fuel or other materials, breakdowns of equipment, acts,
demands or requirements of any federal, state or local governmental authority.

                 (iii) As soon as practicable after such notification the
parties shall consult together to decide how if at all the effects of the force
majeure can be mitigated.

         Section 18.  Relationship of Parties.  The relationship of AccuMed
and Difco shall be solely that of licensor and licensee or lessee and lessor,
as the case may be.  Except as otherwise provided herein, nothing contained
herein shall be construed to





                                       16
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imply a joint venture or other principal and agent relationship between the
parties, and neither party shall have any right, power or authority to create
any obligation, express or implied on behalf of the other.

         Section 19.  Difco Extraordinary Transaction.  Nothing in this
Agreement is intended to, nor shall, restrict, limit or prevent in any fashion
the ability of Difco to consummate any merger, sale of assets or other business
combination transaction and no covenants of Difco or any covenants imposed on
any Affiliate of Difco hereunder, if any, shall bind or apply to any acquiror
or its Affiliates or assets solely by virtue of this Agreement, except only
those imposing obligations of confidentiality.

        [The remainder of this page has been left blank intentionally.]





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          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be duly executed by their respective authorized officers as of the day and year
first above written.


                                        ACCUMED INTERNATIONAL, INC.


                                        By: /s/ Michael D. Burke
                                            -----------------------------------
                                            Michael D. Burke
                                            President, Microbiology
                                            Division



                                        DIFCO LABORATORIES INCORPORATED


                                        By: /s/ William B. Burnett
                                            -----------------------------------
                                            William B. Burnett
                                            President





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