Exhibit 10.12


                             MUREX DIAGNOSTICS LIMITED
                                     DARTFORD
               --------------------------------------------------
                                    MEMORANDUM
               --------------------------------------------------



     Date:     12th January 1996
     From:     Mr D Tholen
     To:       Mr G Guidetti

               Dear Mr Guidetti,

               Murex  Diagnostics   Limited  (the  "Company"),  considers  the
               establishment and maintenance of sound and vital management  to
               be essential to protecting and enhancing the best interests  of
               the  Company and  its  shareholders. In  this  connection,  the
               Company recognizes that the  possibility of a Change in Control
               (as  defined below) may  arise and  that such  possibility, and
               the   uncertainty   and   questions  which   may   arise  among
               management,  may result  in  the departure  or  distraction  of
               management personnel to  the detriment  of the Company and  its
               shareholders.  Accordingly,  the  Board  of  Directors  of  the
               Company (the  "Board") has  determined  that appropriate  steps
               should  be  taken to  reinforce  and  encourage  the  continued
               attention   and  dedication   of  members   of   the  Company's
               management  to  their  assigned duties  without  distraction in
               circumstances  arising from  the  possibility of  a  Change  in
               Control of the  Company's holding company,  International Murex
               Technologies  Corporation ("IMTC").  In  particular,  the Board
               believes  it is  important,  should IMTC  or  its  shareholders
               receive a  proposal for transfer of  control of  IMTC, that you
               be able  to assess and advise  the Board  whether such approval
               would  be  in  the  best  interest   of  the  company  and  its
               shareholders  and to  take  such other  action  regarding  such
               proposal  as  the Board  might  determine  to  be  appropriate,
               without  being influenced  by  the uncertainties  of  your  own
               situation. 

               In order to induce you to remain in the employ of the  Company,
               this  letter ("Agreement"),  which  has been  approved  by  the
               Board,  sets forth  the severance  benefits which  the  Company
               agrees  will  be  provided  to  you  in  the  event  that  your
               employment  with the  Company  is terminated  subsequent  to  a
               Change in  Control of  IMTC under  the circumstances  described
               below. In  the event of a Change in Control,  all payments made
               pursuant to this  Agreement will exclude any redundancy  and/or
               contractual notice  provisions  that  exceed  statutory  notice
               provisions. In addition,  all statutory notice provisions  will
               be  deemed to  be included  in  payments  made pursuant  to the
               terms  of  this  Agreement. The  terms  of  this  Agreement are
               hereby incorporated into your contract of employment. 


                                                                   cont/......
     <PAGE>
                                       -2-

               IMTC  shall establish  an irrevocable  grantor trust  and  make
               contributions thereto sufficient to satisfy  its obligations of
               this Agreement  immediately upon an  event which constitutes  a
               Change in Control (as defined below).

               1.        Change in Control 
                         -----------------

                         For   purposes  of  this  Agreement,   a  "Change  in
                         Control" means and  shall be  deemed to occur if  any
                         of the following occurs: 

               1.1       An  acquisition,  after  September  1,  1995,  by  an
                         individual, entity  or group  of beneficial ownership
                         of 20% or more  of either (i)  the outstanding shares
                         of common stock, no par value,  of IMTC (the  "Common
                         Shares"), or  (ii) the combined  voting power of  the
                         voting securities of IMTC entitled to vote  generally
                         in   the   election   of   directors   (the   "Voting
                         Securities"); 

               1.2       The board of  directors of IMTC ceases to comprise  a
                         majority of directors who either  were holding office
                         on  September   1,  1995  or   were  appointed  after
                         September 1, 1995  with the approval of the  majority
                         of  the  directors  holding  office  on September  1,
                         1995; 

               1.3       Approval by the shareholders of  IMTC of (i) a tender
                         offer to acquire 20% or more  of the Common Shares or
                         Voting  Securities, (ii)  a reorganization,  (iii)  a
                         merger,  or  (iv)  a  consolidation,  other  than   a
                         reorganization,  merger or consolidation with respect
                         to which all or substantially all of the  individuals
                         and  entities   who  were   the  beneficial   owners,
                         immediately prior to such  reorganization, merger  or
                         consolidation,  of  the  Common  Shares  and   Voting
                         Securities  beneficially own, directly or indirectly,
                         immediately  after  such  reorganization,  merger  or
                         consolidation, more that  80% of the then outstanding
                         Common  Shares  and  Voting  Securities (entitled  to
                         vote generally in the election of directors) of  IMTC
                         resulting   from   such  reorganization,   merger  or
                         consolidation  in substantially  the same proportions
                         as their respective ownership,  immediately prior  to
                         such reorganization, merger or consolidation, of  the
                         Common Shares or Voting Securities; 

               1.4       The passing of a resolution to  wind up IMTC and  the
                         approval by the IMTC board or IMTC's shareholders  of
                         the   sale   or   other   disposition   of   all   or
                         substantially all of the assets of IMTC. 

                                                                    cont/.....
     <PAGE>

                                        -3-


               2.        Compensation during Disability
                         ------------------------------

                         During any period you are still employed following  a
                         Change  in Control  that  you fail  to  perform  your
                         duties as a result  of incapacity due  to physical or
                         mental illness,  you shall  continue to  receive your
                         basic  salary at  the rate  then  in effect  and  any
                         other  benefits or  awards shall  continue  to accrue
                         during such period. 

               3.        Termination following a Change in Control
                         -----------------------------------------

                         In  this  paragraph, the  following words  shall have
                         the following meanings:

               3.1       Disability: means your absence from your duties
                         ----------
                         with  the Company  on a  full-time basis  for  ninety
                         (90) consecutive days or an aggregate of ninety  (90)
                         days  in any one  calendar year  as a  result of your
                         incapacity  due to physical or  mental illness UNLESS
                         within thirty  (30) days after  notice of termination
                         is given  to you  following such  absence, you  shall
                         have  returned to  the full-time  performance of your
                         duties pursuant to a doctor's written release; 

               3.2       Cause: means 
                         -----

               3.2.1     The willful and  continued failure by you to  perform
                         materially your duties  with the Company  (other than
                         any such failure  resulting from your incapacity  due
                         to  physical  or  mental  illness)  after  a  written
                         notice for  such performance is  delivered to you  by
                         the President or  the Board  of the Company prior  to
                         any Change  of Control  which specifically identifies
                         the manner(s)  in which  the President  or the  Board
                         believes  that you  have not  performed such material
                         duty; 

               3.2.2     The willful engaging of you in illegal conduct  which
                         is  materially  and  demonstrably  injurious  to  the
                         Company; or 

               3.2.3     A criminal  conviction  (other  than under  the  Road
                         Traffic Act). 

               3.3       Good Reason: means 
                         -----------

               3.3.1     Termination   by  you  during   the  first  (1st)  or
                         thirteenth (13th)  month of  a Change  in Control  of
                         the Company;       
                                                                   cont/......
     <PAGE>
                                        -4-


               3.3.2     A  determination by you, in your reasonable judgment,
                         that  there has  been a  material adverse  change  in
                         your status  or position(s)  as a  senior manager  of
                         the Company during the first month immediately  after
                         the    Change   in    Control,   including,   without
                         limitation,  a   diminution   of   your   duties   or
                         responsibilities  or the  assignment  to  you of  any
                         duties  or  responsibilities which  are  inconsistent
                         with such  status or position(s),  or any removal  of
                         you from,  or any  failure to  reappoint or  re-elect
                         you to, such position(s); 

               3.3.3     A reduction by the Company in your basic salary  from
                         that in  effect immediately  prior to  the Change  in
                         Control; 

               3.3.4     The failure by the Company to continue in effect  any
                         scheme or  plan including pension  plan in which  you
                         are  participating  at the  time  of  the  Change  in
                         Control  (or  plans  providing  you  with  at   least
                         substantially similar benefits) or  the taking of any
                         action, or the  failure to act, by the Company  which
                         would  adversely affect  your continued participation
                         in  any  of  such  scheme  or  plan  on  at  least as
                         favorable a basis to you as  is the case on  the date
                         of the  Change in Control  or which would  materially
                         reduce  your benefits in the future under any of such
                         scheme  or  plans or  deprive  you  of  any  material
                         benefit enjoyed by you at the  time of the Change  in
                         Control; 

               3.3.5     A reduction in your holiday entitlement; 

               3.3.6     The  Company's  requiring you  to  be  based  at  any
                         office which  is greater than  fifty (50) miles  from
                         where  your offices  is located immediately  prior to
                         the Change in Control; 

               3.3.7     Any  refusal by the Company to continue  to allow you
                         to  attend to  matters or  engage in  activities  not
                         directly  related  to the  business  of  the  Company
                         which,  prior to  the  Change in  Control,  you  were
                         permitted by the Board to attend or to engage in. 

               3.4       In the event of: 

               3.4.1     A Change in Control; 

               3.4.2     Your  employment  with  the Company  being terminated
                         within twenty-four (24) months  after such Change  in
                         Control; and 

               3.4.3     Such termination  is not  because of  your death,  by
                         the Company for Cause or Disability, or by you  other
                         than for Good Reason 
                                                                   cont/......
     <PAGE>
                                        -5-

               You shall be entitled to the following: 

               3.4.4     All outstanding  emoluments and benefits  to the date
                         of termination; 

               3.4.5     An amount in cash equal to: 

               3.4.5.1   The higher of two times (i) your annual basic  salary
                         on  the date  of  termination, or  (ii)  your  annual
                         basic  salary  in  effect  immediately prior  to  the
                         Change in Control, plus 

               3.4.5.2   An  amount equal  to two  times  the average  of  the
                         bonuses, if any, awarded to you  in each of the three
                         calendar years  immediately  preceding  the  date  of
                         termination, plus 

               3.4.5.3   An amount equal to two times  the annual value of the
                         benefits enjoyed  by you  and your  family with  your
                         employment  (including  without limitation  a company
                         car,  expenses,  insurance contributions  of whatever
                         nature, (Company  contribution to pension plan  etc.)
                         on the  date of termination  or immediately prior  to
                         the Change in Control whichever is the higher, 

               3.4.5.4   Provided always that  if you employment is terminated
                         by  you  in the  thirteenth  (13th)  month  for  Good
                         Reason  as  defined  in  clause  3.3.1,  those  items
                         included in this paragraph 3.4.5 shall be limited  to
                         the annual value. 

               3.4.6     Reimbursement    of   all    documented    incidental
                         outplacement expenses  directly related  to your  job
                         search  as resume  mailing, interviewing  trips,  and
                         clerical  support,  subject  to   a  maximum  sum  of
                         15,000 Pounds. 

               3.4.7     The  amount  of any  payment  provided  for  in  this
                         paragraph shall not be reduced, offset or subject  to
                         recovery   by   the   Company   by   reason  of   any
                         compensation  earned   by  you  as   the  result   of
                         employment  by another  employer  after  the date  of
                         termination, or otherwise. 

               3.5       For  purposes  of  this  paragraph  3,  the  date  of
                         termination of your employment will be: 

               3.5.1     The date you give notice of termination, or 

               3.5.2     90 days  after the date the  Company gives notice  of
                         termination. 
                                                                   cont/......
     <PAGE>

                                       -6-

               If  this  letter  correctly  sets forth  our  Agreement  on the
               subject matter  hereof, kindly sign  and return  to the Company
               the  enclosed copy  of  the letter  which  then  constitute our
               Agreement on this subject.


               Very truly yours,

               MUREX DIAGNOSTICS LIMITED

                /s/ J. David Tholen

               J. David Tholen
               President and CEO



               AGREED TO AND ACCEPTED:


               By      /s/ Guido Guidetti       
                    ----------------------------


               Date    29/Jan/96                
                    ----------------------------