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                                                                   EXHIBIT 10.15


                                    EXHIBIT A
                             MASTER LEASE AGREEMENT

MASTER LEASE AGREEMENT ("Master Agreement") made as of September 1, 1998,
between VARILEASE CORPORATION, a Michigan corporation, having its chief
executive offices at 28525 Orchard Lake Road, Farmington Hills, MI 48334
("Lessor") and Oacis Healthcare Holdings Corporation, a Delaware corporation
having its chief executive offices at 300 Drake's Landing Road, Suite 1000
("Lessee").

1.      LEASE

On the terms and conditions of this Master Agreement, Lessor shall lease to
Lessee, and Lessee shall hire from Lessor, the items of personal property
described in the Schedule(s) (collectively the "Equipment", and individually an
"Item") which shall incorporate this Master Agreement. Each Schedule shall
constitute a separate and independent lease and contractual obligation of
Lessee. The term "Lease" shall refer to an individual Schedule which
incorporates this Master Agreement. In the event of a conflict between this
Master Agreement and any Schedule, the language of the Schedule shall prevail.
The Lease shall be effective upon execution by Lessor at its offices.

2.      TERM

(a)     The term of the Lease shall be comprised of a Delivery Term,
        Installation Term and Base Term. The Delivery Term for each Item shall
        commence on the date the Item is delivered to Lessee and shall end on
        the Installation Date. The Installation Term shall commence on the
        Installation Date and terminate on the first day of the month following
        the Installation Date for the last Item to be installed (the "Base Term
        Commencement Date"). The Base Term of the Lease shall begin on the Base
        Term Commencement Date, and may, subject to Subsection 2(b), terminate
        on the last day of the last month of the Base Term. The date of
        installation (the "Installation Date") for any Item shall be the earlier
        of either (i) the date on which the entity responsible for installing
        such Item certifies that the Item is installed and placed in good
        working order, or (ii) if Lessee has caused a delay in the installation
        of an Item, seven days from the date the Item is delivered to the
        equipment location specified in the Schedule, or (iii) if Lessee is to
        install the Item, the third day after delivery. In the event the
        Equipment is already installed at the equipment location of Lessee and
        has been previously paid for by Lessee, the Installation Date shall be
        the date on which the Lessor pays Lessee for the Equipment.

(b)     A Lease may be terminated as of the last day of the last month of the
        Base Term by written notice given by either Lessor or Lessee not less
        than six (6) months prior to the date of termination of the Base Term.
        If the Lease is not so terminated at the end of the Base Term, the Base
        Term shall be automatically extended for successive six (6) month
        periods until such six (6) month notice is given. The Base Monthly
        Rental, as hereinafter defined, shall continue to be due and payable by
        Lessee until the Equipment is redelivered to Lessor upon the termination
        of the Base Term or any extension term, and throughout any such
        extension term(s). No notice of termination may be revoked without the
        written consent of the other party.

3.      RENTAL

(a)     The rental amount payable to Lessor by Lessee for the Equipment will be
        as set forth on the Schedule ("Base Monthly Rental"). As rent for
        Equipment, Lessee shall pay Lessor in immediately available funds and in
        advance on the Base Term Commencement Date and on the first day of each
        month during the Base Term of the Lease the Base Monthly Rental, per
        month, and (ii) on the Installation Date an amount equal to 1/30th of
        the Base Monthly Rental for each Item times the number of days which
        will elapse from the Installation Date of such Item to the Base Term
        Commencement Date of the Lease. Each remittance from Lessee to Lessor
        shall contain information as to the Lease for which payment is made.

(b)     For any payment of rent or other amount due under a Lease which is past
        due for more than five (5) days, interest shall accrue at the rate of 2%
        per month, from the date such payment was due until payment is received
        by Lessor, or if such rate shall exceed the maximum rate of interest
        allowed by law, then at such maximum rate.

4.      TAXES

Lessee shall reimburse Lessor for (or pay directly, but only if instructed by
Lessor) all taxes, fees, and assessments that may be imposed by any taxing
authority on the Equipment, on its purchase, ownership, delivery, possession,
operation, rental, return to Lessor or its purchase by Lessee (collectively,
Taxes); provided, however, that Lessee shall not be liable for any such Taxes
(whether imposed by the United States of America or by any other domestic or
foreign taxing authority) imposed on or measured by Lessor's net income or tax
preference items. Lessee's obligation includes, but is not limited to, the
obligation to pay all license and registration fees and all sales, use, personal
property, recordation and other



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taxes and governmental charges, together with any penalties, fines and interest
thereon, that may be imposed during the Base Term of the applicable Schedule.
Lessor shall report and file any and all Taxes and shall invoice Lessee for
same. Lessee shall promptly reimburse Lessor for all Taxes and hold Lessor
harmless with respect to any non-payment thereof.

5.      NET LEASE

The Lease is a net lease, it being the intention of the parties that all costs,
expenses and liabilities associated with the Equipment or its lease shall be
borne by Lessee. Lessee's agreement to pay all obligations under the Lease,
including but not limited to Base Monthly Rental, is absolute and unconditional
and such agreement is for the benefit of Lessor and its Assignee(s). Lessee's
obligations shall not be subject to any abatement, deferment, reduction, setoff,
defense, counterclaim or recoupment for any reason whatsoever. Except as may be
otherwise expressly provided in the Lease, it shall not terminate, nor shall the
obligations of Lessee be affected by reason of any defect in or damage to, or
any loss or destruction of, or obsolescence of, the Equipment or any Item from
any cause whatsoever, or the interference with its use by any private person,
corporation or governmental authority, or as a result of any war, riot,
insurrection or an Act of God. It is the express intention of Lessor and Lessee
that all rent and other sums payable by Lessee under the Lease shall be, and
continue to be, payable in all events throughout the term of the Lease. The
Lease shall be binding upon the Lessee, its successors and permitted assigns and
shall inure to the benefit of Lessor and its Assignee(s).

6.      INSTALLATION, RETURN AND USE OF EQUIPMENT

(a)     Upon delivery of the Equipment to Lessee, Lessee shall pay all
        transportation, installation, rigging, packing and insurance charges
        with respect to the Equipment. In the case of a sale and leaseback
        transaction, Lessee shall, upon the request of Lessor, certify the date
        the Equipment was first put into use. Lessee will provide the required
        electric current and a suitable place of installation for the Equipment
        with all appropriate facilities as specified by the manufacturer. No
        cards, tapes, disks, data cells or other input/output and storage media
        may be used by Lessee to operate any Item unless it meets the
        specifications of the manufacturer. Lessee agrees that it will not
        install, or permit the installation of, the Equipment without Lessor's
        consent.

(b)     Lessee shall, at all times during the term of the Lease, be entitled to
        unlimited use of the Equipment. Lessee will at all times keep the
        Equipment in its sole possession and control. The Equipment shall not be
        moved from the location stated in the Schedule without the prior written
        consent of Lessor and in no event shall the Equipment be moved outside
        the continental, contiguous United States. Lessee will comply with all
        laws, regulations, and ordinances, and all applicable requirements of
        the manufacturer of the Equipment which apply to the physical
        possession, use, operation, condition, and maintenance of the Equipment.
        Lessee agrees to obtain all permits and licenses necessary for the
        operation of the Equipment.

(c)     Lessee shall not without the prior written consent of Lessor, affix or
        install any accessory, feature, equipment or device to the Equipment or
        make any improvement, upgrade, modification, alteration or addition to
        the Equipment (any such accessory, feature, equipment, device or
        improvement, upgrade, modification, alteration or addition affixed or
        installed is an "Improvement"). Title to all Improvements shall, without
        further act, upon the making, affixing or installation of such
        Improvement, vest solely in Lessor, except such Improvements as may be
        readily removed without causing material damage to the Equipment and
        without in any way affecting or impairing the originally intended
        function, value or use of the Equipment. Removal of the Improvement
        shall be performed by the manufacturer, at the sole expense of Lessee.
        Provided the Equipment is returned to Lessor in the condition required
        by the Lease, including, but not limited to coverage under the
        manufacturer's standard maintenance contract, title to the Improvement
        shall vest in the Lessee upon removal. Any Improvement not removed from
        the Equipment prior to return shall at Lessor's option remain the
        property of Lessor and shall be certified for maintenance by the
        manufacturer, at Lessee's expense.

        Lessee shall notify Lessor in writing no less than 60 days prior to the
        desired installation date of the type of Improvement Lessee desires to
        obtain. Lessor may, at any time within 10 days after receipt of the
        notice offer to provide the Improvement to Lessee upon terms and
        conditions to be mutually agreed upon. Lessee shall notify Lessor of any
        third party offers and shall lease the Improvement from Lessor if Lessor
        meets the terms of the third party offer.

        If Lessee leases an Improvement from Lessor, such lease shall be under a
        separate Schedule, the Improvement shall not be placed in service by
        Lessee prior to acquisition by Lessor, and Lessee shall execute and
        deliver any document necessary to vest title to such Improvement in
        Lessor.

        During the term of the Lease term and any renewal term, Lessee shall
        cause all Improvements to be maintained, at Lessee's expense, in
        accordance with the requirements of Section 7. Unless otherwise agreed
        to by Lessor, upon the expiration or earlier termination of the term of
        the Lease, any Improvement shall be de-installed and removed from the
        Equipment by the manufacturer, at Lessee's expense. If the Improvement
        is removed, the Equipment shall be restored to its unmodified condition
        and shall be certified for maintenance by the manufacturer, at Lessee's
        expense.



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        In the event an Improvement is provided to Lessee by a party other than
        Lessor, Lessee shall cause such party to execute and deliver to Lessor
        such documents as shall be required by Lessor to protect the interests
        of Lessor and any Assignee in the Equipment, this Master Agreement and
        any Schedule.

(d)     Lessee shall, at the termination of the Lease, at its expense,
        de-install, pack and return the Equipment to Lessor at such location
        within the continental United States as shall be designated by Lessor in
        the same operating order, repair, condition and appearance as of the
        Installation Date, reasonable wear and tear excepted, with all current
        engineering changes prescribed by the manufacturer of the Equipment or a
        maintenance contractor approved by Lessor (the "Maintenance
        Organization") incorporated in the Equipment. Until the return of the
        Equipment to Lessor, Lessee shall be obligated to pay the Base Monthly
        Rental and all other sums due under the Lease. Upon redelivery to
        Lessor, Lessee shall arrange and pay for such repairs (if any) as are
        necessary for the manufacturer of the Equipment to accept the Equipment
        under a maintenance contract at its then standard rates.

7.      MAINTENANCE AND REPAIRS

Lessee shall, during the term of the Lease, maintain in full force and effect a
contract with the manufacturer of the Equipment or Maintenance Organization
covering at least prime shift maintenance of the Equipment. Lessee upon request
shall furnish Lessor with a copy of such maintenance contract as amended or
supplemented. During the term of the Lease, Lessee shall, at its expense, keep
the Equipment in good working order, repair, appearance and condition and make
all necessary adjustments, repairs and replacements, all of which shall become
the property of Lessor. Lessee shall not use or permit the use of the Equipment
for any purpose for which, in the opinion of the manufacturer of the Equipment
or Maintenance Organization, the Equipment is not designed or intended.

8.      OWNERSHIP, LIENS AND INSPECTIONS

(a)     Lessee shall keep the Equipment free from any marking or labeling which
        might be interpreted as a claim of ownership by Lessee or any party
        other than Lessor and its Assignee(s), and shall affix and maintain
        tags, decals or plates furnished by Lessor on the Equipment indicating
        ownership and title to the Equipment in Lessor or its Assignee(s). Upon
        reasonable notice to Lessee, Lessor or its agents shall have access to
        the Equipment and Lessee's books and records with respect to the Lease
        and the Equipment at reasonable times for the purpose of inspection and
        for any other purposes contemplated by the Lease, subject to the
        reasonable security requirements of Lessee.

(b)     Lessee shall execute and deliver such instruments, including Uniform
        Commercial Code financing statements, as are required to be filed to
        evidence the interest of Lessor and its Assignee(s) in the Equipment or
        the Lease. Lessee has no interest in the Equipment except as expressly
        set forth in the Lease, and that interest is a lease-hold interest.
        Lessor and Lessee agree, and Lessee represents for the benefit of Lessor
        and its Assignee(s) that the Lease is intended to be a "finance lease"
        and not a "lease intended as security " as those terms are used in the
        Uniform Commercial Code; and that the Lease is intended to be a "true
        lease" as the term is commonly used under the Internal Revenue Code of
        1986, as amended.

(c)     LESSEE SHALL KEEP THE LEASE, THE EQUIPMENT AND ANY IMPROVEMENTS FREE AND
        CLEAR OF ALL LIENS AND ENCUMBRANCES OF WHATSOEVER KIND (EXCEPT THOSE
        CREATED BY LESSOR) AND LESSEE SHALL NOT ASSIGN THE LEASE OR ANY OF ITS
        RIGHTS UNDER THE LEASE OR SUBLEASE ANY OF THE EQUIPMENT OR GRANT ANY
        RIGHTS TO THE EQUIPMENT WITHOUT THE PRIOR WRITTEN CONSENT OF LESSOR. No
        permitted assignment or sublease shall relieve Lessee of any of its
        obligations under the Lease and Lessee agrees to pay all costs and
        expenses Lessor may incur in connection with such sublease or
        assignment. Lessee grants to Lessor the right of first refusal on any
        sublease or other grant of Lessee's rights to the Equipment.

9.      DISCLAIMER OF WARRANTIES

(a)     LESSOR LEASES THE EQUIPMENT "AS IS," AND BEING NEITHER THE MANUFACTURER
        OF THE EQUIPMENT NOR THE AGENT OF EITHER THE MANUFACTURER OR SELLER,
        LESSOR DISCLAIMS ANY REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR
        IMPLIED, WITH RESPECT TO THE CONDITION OR PERFORMANCE OF THE EQUIPMENT,
        ITS MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR WITH RESPECT
        TO PATENT INFRINGEMENTS OR THE LIKE. LESSOR SHALL HAVE NO LIABILITY TO
        LESSEE FOR ANY CLAIM, LOSS OR DAMAGE OF ANY KIND OR NATURE WHATSOEVER,
        NOR SHALL THERE BE ANY ABATEMENT OF RENTAL FOR ANY REASON INCLUDING
        CLAIMS ARISING OUT OF OR IN CONNECTION WITH (i) THE DEFICIENCY OR
        INADEQUACY OF THE EQUIPMENT FOR ANY PURPOSE, WHETHER OR NOT KNOWN OR
        DISCLOSED TO LESSOR, (ii) ANY DEFICIENCY OR DEFECT IN THE EQUIPMENT,
        (iii) THE USE OR PERFORMANCE OF THE EQUIPMENT, OR (iv) ANY LOSS OF
        BUSINESS OR OTHER CONSEQUENTIAL LOSS OR DAMAGE, WHETHER OR NOT RESULTING
        FROM ANY OF THE FOREGOING.



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(b)     For the term of the Lease, Lessor assigns to Lessee (to the extent
        possible), and Lessee may have the benefit of, any and all
        manufacturer's warranties, service agreements and patent indemnities, if
        any, with respect to the Equipment; provided, however, that Lessee's
        sole remedy for the breach of any such warranty, indemnification or
        service agreement shall be against the manufacturer of the Equipment and
        not against Lessor, nor shall any such breach have any effect whatsoever
        on the rights and obligations of Lessor or Lessee with respect to the
        Lease.

(c)     NO REPRESENTATIONS OR WARRANTIES OF THE MANUFACTURER OR DISTRIBUTOR OF
        THE EQUIPMENT, OR ANY OTHER THIRD PARTY, CAN BIND LESSOR, AND LESSEE
        ACKNOWLEDGES AND AGREES THAT LESSOR SHALL HAVE NO OBLIGATIONS WITH
        RESPECT TO THE EQUIPMENT EXCEPT AS SPECIFICALLY SET FORTH HEREIN OR
        OTHER DOCUMENT EXECUTED BY LESSOR.

10.     ASSIGNMENT

(a)     Lessee acknowledges and understands that Lessor may assign to a
        successor, financing lender and/or purchaser (the "Assignee"), all or
        any part of the Lessor's right, title and interest in and to the Lease
        and the Equipment and Lessee hereby consents to such assignment(s). In
        the event Lessor transfers or assigns, or retransfers or reassigns, to
        an Assignee all or part of Lessor's interest in the Lease, the Equipment
        or any sums payable under the Lease, whether as collateral security for
        loans or advances made or to be made to Lessor by such Assignee or
        otherwise, Lessee covenants that, upon receipt of notice of any such
        transfer or assignment and instructions from Lessor,

        (i)    Lessee shall, if so instructed, pay and perform its obligations
               under the Lease to the Assignee (or to any other party designated
               by Assignee), and shall not assign the Lease or any of its rights
               under the Lease or permit the Lease to be amended, modified, or
               terminated without the prior written consent of Assignee; and

        (ii)   Lessee's obligations under the Lease with respect to Assignee
               shall be absolute and unconditional and not be subject to any
               abatement, reduction, recoupment, defense, offset or counterclaim
               for any reason, alleged or proven, including, but not limited to,
               defect in the Equipment, the condition, design, operation or
               fitness for use of the Equipment or any loss or destruction or
               obsolescence of the Equipment or any part, the prohibition of or
               other restrictions against Lessee's use of the Equipment, the
               interference with such use by any person or entity, any failure
               by Lessor to perform any of its obligations contained in the
               Lease, any insolvency or bankruptcy of Lessor, or for any other
               cause; and

        (iii)  Lessee shall, upon request of Lessor, submit documents and
               certificates as may be reasonably required by Assignee to secure
               and complete such transfer or assignment, including but not
               limited to the documents set forth in Section 15(c) of this
               Master Agreement.

        (iv)   Lessee shall deliver to Assignee copies of any notices which are
               required under the Lease to be sent to Lessor; and

        (v)    Lessee shall, if requested, restate to Assignee the
               representations, warranties and covenants contained in the Lease
               (upon which Lessee acknowledges Assignee may rely) and shall make
               such other representations, warranties and covenants to Assignee
               as may be reasonably required to give effect to the assignment.

(b)     Lessor shall not make an assignment or transfer to any Assignee who
        shall not agree that, so long as Lessee is not in default under the
        Lease, such Assignee shall take no action to interfere with Lessee's
        quiet enjoyment and use of the Equipment in accordance with the terms of
        the Lease. No such assignment or conveyance shall relieve Lessor of its
        obligations under the Lease and Lessee agrees it shall not look to any
        Assignee to perform any of Lessor's obligations under the Lease. No such
        assignment shall increase Lessee's obligations nor decrease Lessee's
        rights hereunder.

11.     QUIET ENJOYMENT

Lessor covenants that so long as Lessee is not in default under a Lease, Lessor
shall take no action to interfere with Lessee's possession and use of the
Equipment subject to and in accordance with the provisions of the Lease.

12.     INDEMNIFICATION

Except for the sole and gross negligence or willful misconduct of Lessor or
Assignee, Lessee shall and does agree to indemnify, protect, defend, save and
keep harmless Lessor and its Assignee(s) from and against any and all
liabilities, obligations, losses, damages, penalties, claims, actions, suits,
costs, or expenses of any kind and nature whatsoever, including but not limited
to attorneys fees, including without limitation



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attorneys fees in connection with the enforcement of this indemnification, which
may be imposed upon, incurred by or asserted against Lessor or its Assignee(s)
in any way relating to or arising out of the Lease, the manufacture, ownership,
lease, possession, use, condition, operation, or accident in connection with the
Equipment (including, without limitation, those claims based on latent and other
defects, whether or not discoverable, or claims based on strict liability, or
any claim for patent, trademark or copyright infringement). Lessor's rights
arising from this Section shall survive the expiration or other termination of
the Lease. Nothing in this Section shall limit or waive any right of Lessee to
proceed against the manufacturer of the Equipment.

13.     RISK OF LOSS

(a)     Lessee assumes and shall bear the entire risk of loss and damage,
        whether or not insured against, of the Equipment from any and every
        cause whatsoever as of the date the Equipment is delivered to Lessee.

(b)     In the event of loss or damage of any kind to any Item, Lessee shall use
        all reasonable efforts to place the Item in good repair, condition and
        working order to the reasonable satisfaction of Lessor within sixty (60)
        days of such loss or damage, unless the manufacturer of the Equipment
        determines that such Item has been irreparably damaged, in which case
        Lessee shall, within ten (10) days of the manufacturer's determination
        of irreparable loss, make its election to either pay Lessor the
        Stipulated Loss Value (as set forth in Attachment A to this Master
        Agreement) for the irreparably damaged Item or replace the irreparably
        damaged Item, all as provided in this Section. To the extent that the
        Item is damaged but not irreparably damaged and if Lessee is entitled,
        pursuant to the insurance coverage, to obtain proceeds from such
        insurance for the repair of the Item, Lessee (provided no Event of
        Default has occurred under the Lease) may arrange for the disbursement
        of such proceeds to the manufacturer or other entity approved by Lessor
        to perform the repairs to pay the cost of repair. However, Lessee's
        obligation to timely repair the damaged Item is not contingent upon
        receipt of such insurance proceeds.

(c)     In the event that Lessee elects to pay Lessor the Stipulated Loss Value
        for the irreparably damaged Item, Lessee shall (i) pay such amount
        (computed as of the first day of the month following the determination
        of the irreparable damage by the manufacturer) to Lessor on the first
        day of the month following the election by Lessee as provided in (b)
        above, (ii) pay all Base Monthly Rental for the Item up to the date that
        the Stipulated Loss Value is paid to Lessor; and (iii) arrange with the
        applicable insurance company (with the consent of Lessor) for the
        disposition of the irreparably damaged Item. If not all the Equipment is
        irreparably damaged, the Value for Calculation of Stipulated Loss Value
        ("Value") as set forth on the Schedule for the irreparably damaged Item
        shall be multiplied by the applicable percentage set forth in Attachment
        A to compute the Stipulated Loss Value for such irreparably damaged
        Item, and the Base Monthly Rental for the undamaged Equipment remaining
        due (after payment of the Stipulated Loss Value for the irreparably
        damaged Item) shall be that amount resulting from multiplying the
        original Base Monthly Rental by the ratio of the Value of the undamaged
        Equipment divided by the Value for all the Equipment prior to the
        damage.

(d)     If Lessee elects to replace the irreparably damaged Item, Lessee shall
        continue all payments under the Lease without interruption, as if no
        such damage, loss or destruction had occurred, and shall replace such
        irreparably damaged Item, paying all such costs, associated with the
        replacement, and Lessee shall be entitled to insurance proceeds up to
        the amount expended by Lessee in effecting the replacement. Lessee shall
        within twenty (20) days following the date of determination of
        irreparable damage by the manufacturer, effect the replacement by
        replacing the irreparably damaged Item with a "Replacement Item" so that
        Lessor has good, marketable and unencumbered title to such Replacement
        Item. The Replacement Item shall have a fair market value equal to or
        greater than the Item replaced, and anticipated to have a fair market
        value at the expiration of the Base Term equal to the fair market value
        that the replaced Item would have had at the end of the Base Term, and
        be the same manufacture, model and type and of at least equal capacity
        to the Item for which the replacement is being made. Upon delivery, such
        Replacement Item shall become subject to all of the terms and conditions
        of the Lease. Lessee shall execute all instruments or documents
        necessary to effect the foregoing.

(e)     For purposes of this Lease, the term "fair market value" shall mean the
        price of the Equipment delivered and installed at Lessee's location that
        would be obtained in an arm's-length transaction between an informed and
        willing buyer-lessee under no compulsion to buy or lease and an informed
        and willing seller-lessor under no compulsion to sell or lease. If
        Lessor and Lessee are unable to agree upon fair market value, such value
        shall be determined, at Lessee's expense, in accordance with the
        foregoing definition, by three independent appraisers, one to be
        appointed by Lessee, one to be appointed by Lessor and the third to be
        appointed by the first two.

14.     INSURANCE

During the term of the Lease, Lessee, at its own expense, shall maintain in
regard to the Equipment all risk insurance (in an amount not less than the
Stipulated Loss Value as identified on Attachment A) and comprehensive public
liability insurance in amounts and with carriers reasonably satisfactory to
Lessor. Any such insurance shall name Lessor and the Assignee(s) as additional
insured and, as for the all risk insurance, loss payees as their interests may
appear. All such insurance shall provide that it may not be terminated, canceled
or altered without at least thirty



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<PAGE>   6

(30) days' prior written notice to Lessor and its Assignee(s). Coverage afforded
to Lessor shall not be rescinded, impaired, or invalidated by any act or neglect
of Lessee. Lessee agrees to supply to Lessor, upon request, evidence of such
insurance.

15.     REPRESENTATIONS AND WARRANTIES OF LESSEE; FINANCIAL STATEMENTS

(a)     Lessee represents and warrants to Lessor and its Assignee(s) (i) that
        the execution, delivery and performance of this Master Agreement and the
        Lease was duly authorized and that upon execution of this Master
        Agreement and the Lease by Lessee and Lessor, the Master Agreement and
        the Lease will be in full force and effect and constitute a valid legal
        and binding obligation of Lessee, and enforceable against Lessee in
        accordance with their respective terms; (ii) the Equipment is accurately
        described in the Lease and all documents of Lessee relating to the
        Lease; (iii) that Lessee is in good standing in the jurisdiction of its
        incorporation and in any jurisdiction in which any of the Equipment is
        located; (iv) that no consent or approval of, giving of notice to,
        registration with, or taking of any other action in respect of, any
        state, federal or other government authority or agency is required with
        respect to the execution, delivery and performance by the Lessee of this
        Master Agreement or the Lease or, if any such approval, notice,
        registration or action is required, it has been obtained; (v) that the
        entering into and performance of this Master Agreement and the Lease
        will not violate any judgment, order, law or regulation applicable to
        Lessee or any provision of Lessee's Articles of Incorporation or Bylaws
        or result in any breach of, or constitute a default under, or result in
        the creation of any lien, charge, security interest or other encumbrance
        upon any assets of Lessee or upon the Equipment pursuant to any
        instrument to which Lessee is a party or by which it or its property may
        be bound; (vi) there are no actions, suits or proceedings pending, or to
        the knowledge of Lessee, threatened, before any court or administrative
        agency, arbitrator or governmental body which will, if determined
        adversely to Lessee, materially adversely affect its ability to perform
        its obligations under the Lease or any related agreement to which it is
        a party; (vii) that aside from the Master Agreement and the Lease there
        are no additional agreements between Lessee and Lessor relating to the
        Equipment, and (viii) that any and all financial statements and other
        information with respect to Lessee supplied to Lessor at the time of
        execution of the Lease and any amendment, are true and complete. The
        foregoing representations and warranties shall survive the execution and
        delivery of the Lease and any amendments hereto and shall upon the
        written request of Lessor, be made to Lessor's Assignee(s).

(b)     Prior to and during the term of the Lease, Lessee will furnish Lessor
        with Lessee's audited financial statements. If Lessee is a subsidiary of
        another company, Lessee shall supply such company's financial statements
        and guarantees as are reasonably acceptable to Lessor. Lessor's
        obligations to perform under any Lease is subject to the condition that
        the financial statements furnished to Lessor by Lessee present the
        financial condition and results of operations of Lessee and its
        affiliated corporations, if any, and any guarantor of Lessee's
        obligations under any Lease, as of the date of such financial
        statements, and that since the date of such statements there have been
        no material adverse changes in the assets or liabilities, the financial
        condition or other condition which in Lessor's or Assignee(s) sole
        discretion are deemed to be materially adverse. Lessee shall also
        provide Lessor with such other statements concerning the Lease and the
        condition of the Equipment as Lessor may from time to time request.

(c)     Upon Lessor's request, Lessee shall, with respect to each Lease, deliver
        to Lessor (i) a certificate of a secretarial officer of Lessee
        certifying the bylaw, resolution (specific or general) or corporate
        action authorizing the transactions contemplated in the Lease; (ii) an
        incumbency certificate certifying that the person signing this Master
        Agreement and the Lease holds the office the person purports to hold and
        has authority to sign on behalf of Lessee; (iii) an opinion of Lessee's
        counsel with respect to the representations in Section 15(a); (iv) an
        agreement with Lessor's Assignee with regard to any assignment as
        referred to in Section 10; (v) the purchase documents if Lessee has sold
        or assigned its interest in the Equipment to Lessor; (vi) an insurance
        certificate evidencing the insurance provided by Lessee pursuant to
        Section 14; and (vii) an Installation Certificate duly executed by
        Lessee. Failure by Lessee to deliver any of these documents when due
        shall operate, at Lessor's option, to continue the Installation Term for
        the Lease thus delaying the Base Term Commencement Date, or to increase
        the Base Monthly Rental to recover costs incurred by Lessor consequent
        to the delay or the termination of the Lease as provided in Section 16.

16.     DEFAULT, REMEDIES

(a)     The following shall be deemed "Events of Default" under the Lease:

        (1)    Lessee fails to pay any installment of rent or other charge or
               amount due under the Lease within ten (10) days after notice that
               such payment is overdue; or

        (2)    Except as expressly permitted in the Lease, Lessee attempts to
               remove, sell encumber, assign or sublease or fails to insure any
               of the Equipment, or fails to deliver any documents required of
               Lessee under the Lease; or

        (3)    Any representation or warranty made by Lessee or Lessee's
               guarantor in the Lease or any document supplied in connection
               with the Lease or any financial statement is misleading or
               materially inaccurate; or



                                       28
<PAGE>   7

        (4)    Lessee fails to observe or perform any of the other obligations
               required to be observed by Lessee under the Lease within thirty
               (30) days of Lessee's first knowledge of such failure; or

        (5)    Lessee or Lessee's guarantor ceases doing business as a going
               concern; makes an assignment for the benefit of creditors; admits
               in writing its inability to pay its debts as they become due;
               files a voluntary petition in bankruptcy; is adjudicated a
               bankrupt or an insolvent; files a petition seeking for itself any
               reorganization, arrangement, composition, readjustment,
               liquidation, dissolution or similar arrangement under any present
               or future statute, law or regulation or files an answer admitting
               or fails to deny the material allegations of a petition filed
               against it in any such proceeding; consents to or acquiesces in
               the appointment of a trustee, receiver, or liquidator for it or
               of all or any substantial part of its assets or properties, or if
               it or its trustee, receiver, liquidator or shareholders shall
               take any action to effect its dissolution or liquidation; or

        (6)    If within thirty (30) days after the commencement of any
               proceedings against Lessee or Lessee's guarantor seeking
               reorganization, arrangement, composition, readjustment,
               liquidation, dissolution or similar relief under any present or
               future statute, law or regulation, such proceedings shall not
               have been dismissed, or if within thirty (30) days after the
               appointment (with or without Lessee's or Lessee's guarantor's
               consent) of any trustee, receiver or liquidator of it or all of
               or any substantial part of its respective assets and properties,
               such appointment shall not be vacated.

(b)     Upon the happening of any Event of Default, Lessor may declare the
        Lessee to be in default. Lessee authorizes Lessor at any time
        thereafter, with or without terminating the Lease, to enter any premises
        where the Equipment may be and take possession of the Equipment. Lessee
        shall, upon such declaration of default, without further demand,
        immediately pay Lessor an amount which is equal to (i) any unpaid amount
        due on or before Lessor declared the Lease to be in default, plus (ii)
        as liquidated damages for loss of a bargain and not as a penalty, an
        amount equal to the Stipulated Loss Value for the Equipment computed as
        of the date the last Base Monthly Rental payment was due prior to the
        date Lessor declared the Lease to be in default, together with interest,
        as provided herein, plus (iii) all attorney and court costs incurred by
        Lessor relating to the enforcement of its rights under the Lease. After
        an Event of Default, at the request of Lessor and to the extent
        requested by Lessor, Lessee shall immediately comply with the provisions
        of Section 6(d) and Lessor may sell the Equipment at private or public
        sale, in bulk or in parcels, with or without notice, without having the
        Equipment present at the place of sale; or Lessor may lease, otherwise
        dispose of or keep idle all or part of the Equipment, subject, however,
        to its obligation to mitigate damages. The proceeds of sale, lease or
        other disposition, if any, of the Equipment shall be applied: (1) to all
        Lessor's costs, charges and expenses incurred in taking, removing,
        holding, repairing and selling, leasing or otherwise disposing of the
        Equipment including attorney fees; then (2) to the extent not previously
        paid by Lessee, to pay Lessor the Stipulated Loss Value for the
        Equipment and all other sums owed by Lessee under the Lease, including
        any unpaid rent which accrued to the date Lessor declared the Lease to
        be in default and indemnities then remaining unpaid under the Lease;
        then (3) to reimburse to Lessee Stipulated Loss Value previously paid by
        Lessee as liquidated damages; and (4) any surplus shall be retained by
        Lessor. Lessee shall pay any deficiency in (1) and (2) immediately. The
        exercise of any of the foregoing remedies by Lessor shall not constitute
        a termination of the Lease unless Lessor so notifies Lessee in writing.
        Lessor may also proceed by appropriate court action, either at law or in
        equity to enforce performance by Lessee of the applicable covenants of
        the Lease or to recover damages for the breach of the Lease.

(c)     The waiver by Lessor of any breach of any obligation of Lessee shall not
        be deemed a waiver of any future breach of the same or any other
        obligation. The subsequent acceptance of rental payments under the Lease
        by Lessor shall not be deemed a waiver of any such prior existing breach
        at the time of acceptance of such rental payments. The rights afforded
        Lessor under Section 16 shall be cumulative and concurrent and shall be
        in addition to every other right or remedy provided for the Lease or now
        or later existing in law (including as appropriate all the rights of a
        secured party or lessor under the Uniform Commercial Code) or in equity
        and Lessor's exercise or attempted exercise of such rights or remedies
        shall not preclude the simultaneous or later exercise of any or all
        other rights or remedies.

(d)     In the event Lessee shall fail to perform any of its obligations under
        the Lease, then Lessor may perform the same, but shall not be obligated
        to do so, at the cost and expense of Lessee. In any such event, Lessee
        shall promptly reimburse Lessor for any such costs and expenses incurred
        by Lessor.

17.     LESSOR'S TAX BENEFITS

Lessee acknowledges that Lessor shall be entitled to claim all tax benefits,
credits and deductions related to the Equipment for federal income tax purposes
including, without limitation: (i) deductions on Lessor's cost of the Equipment
for each of its tax years during the term of the Lease under any method of
depreciation or other cost recovery formula permitted by the Internal Revenue
Code of 1986, as amended (hereinafter called the "Code"), and (ii) interest
deductions as permitted by the Code on the aggregate interest paid to any
Assignee (hereinafter collectively "Lessor's Tax Benefits"). Lessee agrees to
take no action inconsistent (including the voluntary substitution of Equipment)
with the foregoing or



                                       29
<PAGE>   8

which would result in the loss, disallowance, recapture or unavailability to
Lessor of Lessor's Tax Benefits. Lessee hereby indemnifies Lessor and its
Assignee(s) from and against (a) any loss, disallowance, unavailability or
recapture of Lessor's Tax Benefits resulting from any action or failure to act
of Lessee, including replacement of the Equipment, plus (b) all interest,
penalties, costs, (including attorney fees), or additions to tax resulting from
such loss, disallowance, unavailability or recapture.

18.     GENERAL

(a)     The Lease shall be deemed to have been made and delivered in the State
        of Michigan and shall be governed in all respects by the laws of such
        State. THE PARTIES HERETO AGREE THAT IN THE EVENT OF AN ALLEGED BREACH
        OF THIS AGREEMENT OR ANY DOCUMENTS RELATING THERETO BY EITHER PARTY, OR
        ANY CONTROVERSIES ARISE BETWEEN THE PARTIES RELATING TO THIS AGREEMENT
        OR ANY DOCUMENTS RELATING THERETO, AND SUCH BREACHES OR CONTROVERSIES
        ARE BROUGHT BEFORE ANY COURT, SUCH CONTROVERSIES SHALL BE TRIED BY A
        JUDGE ALONE. THE PARTIES, HAVING HAD THE OPPORTUNITY TO CONSULT WITH
        INDEPENDENT COUNSEL OF THEIR OWN CHOOSING, HEREBY KNOWINGLY AND
        VOLUNTARILY WAIVE THEIR RIGHTS TO A TRIAL BY JURY IN ANY MATTER RELATING
        TO THIS AGREEMENT OR ANY DOCUMENTS RELATED THERETO.

(b)     The Master Agreement and the Lease constitute the entire and only
        agreement between Lessee and Lessor with respect to the lease of the
        Equipment, and the parties have only those rights and have incurred only
        those obligations as specifically set forth herein. The covenants,
        conditions, terms and provisions may not be waived or modified orally
        and shall supersede all previous proposals, both oral and written,
        negotiations, representations, commitments or agreements between the
        parties. The Lease may not be amended or discharged except by a
        subsequent written agreement entered into by duly authorized
        representatives of Lessor and Lessee.

(c)     All notices, consents or requests desired or required to be given under
        the Lease shall be in writing and shall be delivered in person or sent
        by certified mail, return, receipt requested, or by courier service to
        the address of the other party set forth in the introduction of the
        Master Agreement or to such other address as such party shall have
        designated by proper notice.

(d)     Each Schedule shall be executed in three counterparts, consecutively
        numbered. To the extent, if any, that a Schedule constitutes chattel
        paper (as such term is defined in the Uniform Commercial Code) no
        security interest in the Schedule may be created through the transfer or
        possession of any counterpart other than Counterpart No. 1. The Master
        Agreement, in the form of a photocopy, is Exhibit A to the Schedule and
        is not chattel paper by itself.

(e)     Section headings are for convenience only and shall not be construed as
        part of the Lease.

(f)     It is expressly understood that all of the Equipment shall be and remain
        personal property, notwithstanding the manner in which the same may be
        attached or affixed to realty, and, upon Lessor's request, Lessee shall
        secure from its mortgagee, landlord or owner of the premises a waiver in
        form and substance reasonably satisfactory to Lessor.

(g)     Lessor may upon written notice to Lessee advise Lessee that certain
        Items supplied to Lessee are leased to Lessor and supplied to Lessee
        under the Lease as a sublease. Lessee agrees to execute and deliver such
        acknowledgements and assignments in connection with such a Lease as are
        reasonably required. If, at any time during the term of the Lease,
        Lessor's right to lease the Equipment expires, Lessor may remove the
        Equipment from Lessee's premises and shall promptly provide identical
        substitute Equipment. All expenses of such substitution, including
        de-installation, installation and transportation expenses, shall be
        borne by Lessor.

(h)     Prior to the delivery of any Item, the obligations of Lessor hereunder
        shall be suspended to the extent that it is hindered or prevented from
        complying therewith because of: labor disturbances, including strikes
        and lockouts; acts of God; fires; storms; accidents; failure to deliver
        any Item; governmental regulations or interferences or any cause
        whatsoever not within the sole control of Lessor.

(i)     Any provision of the Master Agreement or any Schedule prohibited by or
        unlawful or unenforceable under any applicable law of any jurisdiction
        shall be ineffective as to such jurisdiction without invalidating the
        remaining provisions of the Master Agreement and such Schedule.

(j)     Although this Lease is the standard form used by Lessor to lease
        hardware equipment to Lessee, both Lessor and Lessee acknowledge that,
        with respect to any software which may be included as Equipment
        ("Software"), this Lease is a financing agreement whereby that portion
        of Lessee's Base Monthly Rental payment obligation applicable to any
        Software represents license fees which are being paid by Lessee in
        consideration for payment by Lessor to the software vendor ("Vendor") of
        the total license fee relating to any such Software. Neither Lessor nor
        Lessee have or were granted any ownership or other proprietary rights in
        the Software, and neither party purports to transfer any such rights to
        the other hereunder. Lessee has only those rights in the Software which
        were granted to Lessee pursuant



                                       30
<PAGE>   9

        to the software license agreement entered into directly between Vendor
        and Lessee ("License").The terms of this Lease are applicable only as
        between Lessor (and any Assignee) and Lessee. The terms of the License
        are applicable only as between Lessee and Vendor, and Lessor does not
        assume and is not liable for any obligations under any of the provisions
        of the License. Lessee's Base Monthly Rental payment obligation is
        absolute and unconditional in all respects regardless of any problem
        Lessee may have with the Software, any dispute Lessee may have with the
        Vendor, any inability of Lessee to use the Software, or the exercise by
        Vendor of any remedies it may have pursuant to the License.

(k)     The parties agree that this is a "Finance Lease" as defined by section
        2A-103(g) of the Uniform Commercial Code ("UCC"). Lessee acknowledges
        either (a) that Lessee has reviewed and approved any written Supply
        Contract (as defined by UCC 2-A-103(y)) covering the Equipment purchased
        from the Supplier (as defined by UCC 2A-103(x)) thereof for lease to
        Lessee or (b) that Lessor has informed or advised Lessee, in writing,
        either previously or by this Lease of the following: (i) the identity of
        the Supplier, (ii) that the Lessee may have rights under the Supply
        Contract; and (iii) that the Lessee may contact the Supplier for a
        description of any such rights Lessee may have under the Supply
        Contract.

(l)     The parties acknowledge that serial numbers for one or more Items may be
        unavailable prior to execution of the applicable Schedule. In the event
        a Schedule fails to indicate a serial number for one or more Items,
        Lessee expressly consents to Lessor's unilateral amendment of the
        applicable Schedule to insert accurate serial numbers therein.

The parties have executed this Master Lease Agreement as of the date written
above.

LESSOR:                                    LESSEE:

VARILEASE CORPORATION                      OACIS HEALTHCARE HOLDINGS CORPORATION

By: /s/  Gary F. Miller                    By: /s/  Stephen F. Ghiglieri
   -----------------------------              ----------------------------------

Name:    Gary F. Miller                    Name:    Stephen F. Ghiglieri
     ---------------------------                --------------------------------

By:      Senior Vice President             Title:   Chief Financial Officer
   -----------------------------                 -------------------------------



If there are no Additional Provisions to this Master Lease Agreement, check
here [X]. If there are Additional Provisions describe here:



                                       31
<PAGE>   10



                                  ATTACHMENT A

                            to MASTER LEASE AGREEMENT

                             dated September 1, 1998

                    between VARILEASE CORPORATION ("LESSOR")

              and OACIS HEALTHCARE HOLDINGS CORPORATION ("LESSEE")


        To calculate Stipulated Loss Value, multiply the applicable percentage,
below, by the value of the applicable Item(s) set forth on the Schedule.

<TABLE>
<CAPTION>
RENT                          RENT                      RENT
PAYMENT        STIP LOSS      PAYMENT     STIP LOSS     PAYMENT   STIP LOSS
NUMBER         PERCENT        NUMBER      PERCENT       NUMBER    PERCENT
<S>            <C>              <C>       <C>             <C>     <C>   
  1            110.50%          21        85.31%          41      60.13%
  2            109.24%          22        84.05%          42      58.87%
  3            107.98%          23        82.80%          43      57.61%
  4            106.62%          24        81.54%          44      56.35%
  5            105.46%          25        80.28%          45      55.09%
  6            104.20%          26        79.02%          46      53.83%
  7            102.94%          27        77.76%          47      52.57%
  8            101.68%          28        76.50%          48      51.31%
  9            100.43%          29        75.24%          49      50.05%
  10            99.17%          30        73.98%          50      48.79%
  11            97.91%          31        72.72%          51      47.53%
  12            96.65%          32        71.46%          52      46.28%
  13            95.39%          33        70.20%          53      45.02%
  14            94.13%          34        68.94%          54      43.76%
  15            92.87%          35        67.68%          55      42.50%
  16            91.61%          36        66.42%          56      41.24%
  17            90.35%          37        65.17%          57      39.98%
  18            89.09%          38        63.91%          58      38.72%
  19            87.83%          39        62.65%          59      37.46%
  20            86.57%          40        61.39%          60      36.10%
                                                          AND THEREAFTER
</TABLE>







Lessor: _____                                                      Lessee: _____






                                       32