EXHIBIT 6
 
                          Donaldson, Lufkin & Jenrette
              Donaldson, Lufkin & Jenrette Securities Corporation
    2121 Avenue of the Stars, Suite 3000, Los Angeles, CA 90067-5014 - (310)
                                    282-6161
 
                                                                  March 15, 1998
 
Board of Directors
 
International Murex Technologies Corporation
 
2255 B. Queen Street, East, Suite 828
 
Toronto, ON M4E1G3
 
Dear Sirs:
 
    You have requested our opinion as to the fairness from a financial point of
view to the holders of common shares, without par value ("Company Common
Shares"), of International Murex Technologies Corporation, a British Columbia
company (the "Company" or "IMTC"), of the consideration to be received by such
holders pursuant to the terms of the Acquisition Agreement, dated as of March
13, 1998 (the "Agreement"), among the Company, Abbott Laboratories ("Abbott")
and AAC Acquisition Ltd., a wholly owned subsidiary of Abbott ("Subsidiary"),
pursuant to which Subsidiary will directly or indirectly acquire the Company
(the "Acquisition") either (i) pursuant to the compulsory acquisition procedures
contemplated by the Company Act (British Columbia) (the "BC Act") or (ii)
pursuant to an amalgamation, arrangement or other business combination as
contemplated by the BC Act.
 
    Pursuant to the Agreement, Subsidiary will commence a tender offer (the
"Tender Offer") for all outstanding Company Common Shares at a price of US$13.00
per share in cash. The Tender Offer is to be followed by the Acquisition in
which all holders who did not tender will be entitled to receive US$13.00 per
share in cash for their Company Common Shares.
 
    In arriving at our opinion, we have reviewed the Agreement as well as
financial and other information that was publicly available or furnished to us
by the Company, including information provided during discussions with
management. Included in the information provided during discussions with
management were certain financial projections of the Company for the period
beginning January 1, 1998 and ending December 31, 2002 prepared by the
management of the Company. In addition, we have compared certain financial and
securities data of the Company with various other companies whose securities are
traded in public markets, reviewed the historical stock prices and trading
volumes of the common stock of the Company, reviewed prices and premiums paid in
certain other business combinations and conducted such other financial studies,
analyses and investigations as we deemed appropriate for purposes of this
opinion.
 
    In rendering our opinion, we have relied upon and assumed the accuracy and
completeness of all of the financial and other information that was available to
us from public sources, that was provided to us by the Company or its
representatives, or that was otherwise reviewed by us. With respect to the
financial projections supplied to us, we have assumed that such projections, as
adjusted by management of the Company to reflect recent results, have been
reasonably prepared on the basis reflecting the best currently available
estimates and judgments of the management of the Company as to the future
operating and financial performance of the Company. We have not assumed any
responsibility for making an independent evaluation of any assets or liabilities
or for making any independent verification of any of the information reviewed by
us. In connection with our opinion, we have relied on the advice of counsel to
IMTC with respect to any current settlement value of IMTC's pending patent
litigation with Abbott and have, with IMTC's consent, not taken into account any
value in excess of such value. We have also relied as to certain legal matters
on advice of counsel to the Company.

    Our opinion is necessarily based on economic, market, financial and other
conditions as they exist on, and on the information made available to us as of,
the date of this letter. It should be understood that, although subsequent
developments may affect this opinion, we do not have any obligation to update,
revise or reaffirm this opinion. Our opinion does not address the relative
merits of the Acquisition and the other business strategies being considered by
the Company's Board of Directors, nor does it address the Board's decision to
proceed with the Acquisition. Our opinion does not constitute a recommendation
to any shareholder as to whether such holder should tender any Company Common
Shares in the Tender Offer or how such holder should vote on the Acquisition.
 
    Donaldson, Lufkin & Jenrette Securities Corporation, as part of its
investment banking services, is regularly engaged in the valuation of businesses
and securities in connection with mergers, acquisitions, underwritings, sales
and distributions of listed and unlisted securities, private placements and
valuations for corporate and other purposes.
 
    Based upon the foregoing and such other factors as we deem relevant, we are
of the opinion that the consideration to be received by the holders of the
Company Common Shares pursuant to the terms of the Agreement is fair to such
holders from a financial point of view.
 

                               
                                Very truly yours,
 
                                DONALDSON, LUFKIN & JENRETTE
                                SECURITIES CORPORATION
 
                                By:           /s/ GRANT F. LITTLE, III
                                     -----------------------------------------
                                                Grant F. Little, III
                                               SENIOR VICE PRESIDENT