AMENDMENT TO RIGHTS PLAN

                               AMENDMENT TO RIGHTS PLAN

     This Amendment is made as of the 13th day of March 1998 by and between
International Murex Technologies Corporation, a British Columbia company (the
"Company") and The Bank of New York, as Rights Agent (the "Rights Agent").

                                       RECITALS

     A.   The Company has adopted that certain Shareholder Protection Rights
Agreement (the "Rights Plan") by and between the Company and the Rights Agent
dated August 31, 1995 (all capitalized terms used and not defined herein shall
be as defined in the Rights Plan, as amended herein);

     B.   Pursuant to Section 5.5(d) of the Rights Plan, the President of the
Company has executed and delivered to the Rights Agent a certificate which
states that the proposed amendments to the Rights Plan set forth herein are in
compliance with the terms of Section 5.5 of the Rights Plan;

     C.   Pursuant to an Acquisition Agreement dated as of March 13, 1998 (the
"Acquisition Agreement"), Xxxxxx Laboratories, an Illinois corporation
("Parent") and AAC Acquisition Ltd., a British Columbia company shall acquire
the Company;

     D.   Parent and certain shareholders of the Company have entered into
agreements under which such shareholders shall sell their Voting Shares of the
Company to Parent in furtherance of the Acquisition Agreement;

     E.   The Company and the Rights Agent wish to enter into this Amendment in
furtherance thereof.

                                      AMENDMENT

     NOW, THEREFORE, for good and valid consideration, the receipt and
sufficiency of which are acknowledged, the parties amend the Rights Plan as
follows:

1.   The introductory clause of the definition of "Acquiring Person" set forth
     in Section 1.1(a) is amended in its entirety as follows:

     ""Acquiring Person" means any Person who, together with all Affiliates
     and Associates of such Person, is the Beneficial Owner of 20% or more
     of the then outstanding Voting Shares, (1) excluding Xxxxxx
     Laboratories, an Illinois corporation ("Parent"), AAC Acquisition
     Ltd., a British Columbia company ("Purchaser") and their Subsidiaries, 
     (2) but shall not include:"

2.   The definition of "Separation Time" set forth in Section 1.1(ar) is amended
     to insert the following text immediately preceding the period concluding
     the definition:



     "; and

     (C)  the Separation Time shall not occur by virtue of (w) the
          execution of the Acquisition Agreement by and among the
          Corporation, Parent and Purchaser, (x) the execution of the
          agreements referenced in the Acquisition Agreement by and between
          Parent and certain shareholders to sell their Voting Shares to
          Parent, (y) the consummation of the transactions contemplated or
          permitted thereunder or (z) the acquisition or purchase of Voting
          Shares by Parent, Purchaser or their Subsidiaries"




     IN WITNESS WHEREOF, all parties have executed and delivered this Amendment
as of the date first written above.

INTERNATIONAL MUREX
TECHNOLOGIES CORPORATION


By: /s/ C. Xxxxxx Xxxxxx
   ---------------------------
Name:  C. Xxxxxx Xxxxxx
Title:  President


THE BANK OF NEW YORK,
as Rights Agent


By:
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Name:
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Title:
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