Filed by Automated Filing Services Inc. (604) 609-0244 - Response Biomedical Corp. - Exhibit 4.15






 IRREVOCABLE GUARANTEE AGREEMENT 

 THIS AGREEMENT MADE EFFECTIVE AS OF THE 21ST DAY OF FEBRUARY, 2003 (the "Effective
  Date"). 

 BETWEEN:

RESPONSE BIOMEDICAL CORP.,
  a company duly incorporated pursuant to the laws of British Columbia and an
  office at 8855 Northbrook Court, Burnaby, British Columbia, Canada, V5J 5J1
   (the “Company”) 


 AND:


  DOMINIQUE E. MERZ, of 1305 La Marada St, Laguna Beach
    CA, USA 92651 

  (the "Guarantor") 



 WHEREAS:  

 A.                    the
  Company is entering into a line of credit agreement with The Toronto-Dominion
  Bank ("the "Creditor"), evidenced by the materials attached as Schedule "A"
  for a total of US$100,000 and referred to herein as the "Credit Line
  ", contingent upon the issuance of a suitable standby letter of credit ("LC")
  to the Creditor by Wells Fargo, Laguna Beach CA branch; 

 B.                    the
  Guarantor has agreed to guarantee the LC by providing an unconditional and irrevocable
  guarantee for the amount of US$100,000 (the "Guarantee") to Wells Fargo expiring
  at the office the Creditor on the close of business September 30, 2003; 

 C.                    the
  Guarantor has agreed to accept common share purchase warrants (the "Warrants")
  providing the Guarantor the right to purchase 109,462 common
  shares without par value (the "Shares") in the capital stock of the Company
  as consideration for providing the Guarantee, such Warrants to be exercisable
  at a price of Cdn $0.55 per Share and the total aggregate
  number of Shares calculated based on the Bank of Canada Noon Exchange Rate on
  the effective date of this agreement, of C$/US$1.5051; 

 D.                    the
  Guarantor is a person to whom the Company may issue securities pursuant to the
  exemption (the "Exemptions") provided by B.C. Instrument #72-503 of the British
  Columbia Securities Act, Rules, Regulations, Instruments or Notices;
  and 

 E.                    the
  Warrants will be issued pursuant to the Exemptions and that the Company is relying
  on the Exemptions from the requirements to provide the purchaser with a prospectus
  and to sell securities through a person registered to sell securities under
  the B.C. Securities Act and, as a consequence of acquiring securities
  pursuant to the Exemptions, certain protections, rights and remedies provided
  by the B.C. Securities Act, including statutory rights of rescission
  or damages, will not be available to the purchaser. 

                        NOW
  THEREFORE THIS AGREEMENT WITNESSETH THAT in consideration of the mutual covenants
  and agreements herein contained, the receipt and sufficiency of which is hereby
  acknowledged, the parties covenant and agree with each other (the "Agreement")
  as follows: 






 - 2 -

	1.	On the basis of the representations
        and warranties of the Guarantor contained in this Agreement and subject
        to the terms of this Agreement, the Company agrees to issue the Warrants
        to or at the direction of the Guarantor as full consideration for providing
        the Guarantee.

	 	 
	2.	For the term of the Guarantee, the Company
        agrees to inform the Guarantor of the Credit Line balance by e-mail or
        fax on the last business day of each calendar month.

	 	 
	3.	This Agreement is subject to all necessary
        approvals of the TSX Venture Exchange (the "Exchange") and the B.C. Securities
        Commission (the "Regulators").

	 	 
	4.	Subject to the Creditor having first
        accepted a LC from Bank Sarasin and the Creditor and the Company executing
        the Credit Line, the Company shall deliver a warrant certificate representing
        the Warrants to the Guarantor at his address shown on the first page of
        this Agreement within ten days of receiving written notice of the last
        of the approvals of the Regulators.

	 	 
	5.	The Guarantor acknowledges that the
        Shares will be subject to a four (4) month hold period from the
        date of the issuance of the Warrants imposed by the Exchange and by the
        operation of applicable securities rules or by applicable securities regulatory
        bodies, and that a share certificate issued within four months of issuing
        the Warrants, as a result of exercising the Warrants, will bear legends
        to that effect.

	 	 
	6.	The Guarantor acknowledges that this
        Agreement is not being entered into and the Warrants are not being acquired
        by the Guarantor as a result of any material information about the Company's
        affairs that has not been publicly disclosed.

	 	 
	7.	In the event of any subdivision, consolidation
        or other change in the share capital of the Company prior to the issuance
        of the Warrants, the number of Warrants issued pursuant to this Agreement
        shall be adjusted in accordance with such subdivision, consolidation or
        other change in the share capital of the Company.

	 	 
	8. 	Time shall be of the essence in this
        Agreement.

	 	 
	9.	This Agreement is subject to, governed
        by and construed in accordance with the laws of the Province of British
        Columbia.

	 	 
	10.	All references to funds in this Agreement
        are in Canadian funds unless otherwise noted.

	 	 
	11.	This Agreement shall enure to the benefit
        of and be binding upon the parties hereto and their respective heirs,
        executors, administrators, successors and assigns.

	 	 
	12.	The parties hereto agree to execute
        and deliver all such further documents and other writings of any kind
        whatsoever and all such further acts and things as are reasonably required
        to carry out the full intent and meaning of this Agreement.

	 	 
	13.	Whenever the singular or masculine is
        used in this Agreement the same shall be deemed to include the plural
        or the feminine or the body corporate as the context may require.

	 	 
	14.	This Agreement constitutes the entire
        agreement between the parties and there are no representations, warranties,
        covenants or agreements collateral hereto other than as contained herein.










-3- 

	15.	 This Agreement may be signed in as many counterparts
        as may be deemed necessary, each of which so signed shall be deemed to
        be an original, and all such counterparts together shall constitute one
        and the same instrument.





  

  IN WITNESS WHEREOF the parties have executed this written Agreement effective
  as of the Effective Date.

 SIGNED, SEALED AND DELIVERED BY

  RESPONSE BIOMEDICAL CORP. per:

/s/ William Radak                                                                       

  Authorized Signatory

 Name of Signatory:           William
  Radak                               

 Title of Signatory:             President
  & CEO                          



	SIGNED, SEALED & DELIVERED	)	 
	by DOMINQUE MERZ	)	 
	 in the presence of: 	)	 
	 	)	 
	/s/ Ken Shaw                                                                            
	)	 DOMINQUE E. MERZ
	Signature of Witness 	)	 
	 	)	Per:
	Name:                 Ken
      Shaw                                                      	)	 
	 	)	/s/ Dominique Merz                                                                      
	                      413
      - 789 West 16th Avenue	)	Duly Authorized Signatory of the Guarantor
	 Address:     Vancouver, BC                                
                        
       	)	 
	 	)	 
	Occupation:      Controller                                                       	)	 








  

	WELLS  

      FARGO	WELLS FARGO BANK, N.A.	 
	 	TRADE SERVICES DIVISION, NORTHERN CALIFORNIA	 
	 	525 MARKET STREET, 25TH FLOOR	 
	 	SAN FRANCISCO, CALIFORNIA 94105	 
	 	TEL: 1-800-798.2815, option I	TD BAN K
	 	Fax: (415) 284-9453	OLD REF:   5815761         
	 	Email: sftrade@wellsfargo.com	Page      1    of
          2     PAGES
	 	 	 
	 	IRREVOCABLE LETTER OF CREDIT	 
	 	 	 


 

	Beneficiary:	 
	Toronto Dominion Bank	Letter of Credit No. NZS4'S73$7
	700 West Georgia Street, 2nd Floor	Date: February 13, 2003
	Vancouver, BC V7Y 1A2	Expiry Date: September 30, 2003
	 	at our above counters


 Attn: Kathrin Teichried 

Ladies and Gentlemen: 

 We hereby establish our irrevocable Letter of Credit In your favor for the
  account of Dominique Merz, 591 Temple Hills Drive, Laguna Beach, CA 92651, for
  drawings up to the aggregate amount of One Hundred Thousand and 00/100 United
  States Dollars (US$100,000.00), available by your drafts at sight drawn on Welts
  Fargo, N.A., San Francisco, CA and accompanied by: 


  
     Your signed and dated statement worded as follows. 

           "The undersigned, an authorized representative
      of Toronto Dominion Bank. hereby certifies that this drawing represents
      outstanding and unpaid principal and Interest due and owing, calculated
      up to the value date of the present demand, in connection with an
      agreement between Response Biomedical Corp and Toronto Dominion Bank." 

  




Each draft must be marked: "Drawn under Wells Fargo Bank, N.A. Letter of Credit Nn, NZS467387" and must be accompanied by the original of this Letter of Credit for our endorsement on this Letter of Credit of the amount of our payment on such draft.


 Partial Drawings are permitted (more than one draft may be drawn and presented
  under the Letter of Credit). 


We hereby undertake to promptly honor your sight draft(s) drawn on us in your favor, for all or any part of this Letter of Credit, if presented to us at our above address, on or before the expiry date.


 All banking charges and commissions are for applicant's account. 


If any instructions accompanying a drawing under this Letter of Credit request that payment is to be made by transfer to an account with us or at another bank, we and/or such other bank may rely on an account number specified in such instructions
even if the number identifies a person or entity different from the intended payee.



1







  

	 	TD BAN K
	 	OLD REF:   5815761         
	 	Page      2    of
          2     PAGES



  
     This is an integral part of our Letter of Credit No. NZS467387

  




Documents must be presented to us not later than 5:00 P.M.


 Documents must be forwarded to us via courier in one parcel
  and may be mailed to Wells Fargo Bank, N.A., Trade Services Ops-North Wkstn.A,
  525 Market Street, 25th Floor, MAC A0103-255, San Francisco, CA 94105.

 This Letter of Credit is subject to the Uniform Customs and
  Practice for Documentary Credits (1993 Revision), International Chamber of Commerce
  Publication No. 500 (the "UCP") and engages us in accordance with the terms
  thereof. 

	   	Very truly yours,
	 	 	 
	 	WELLS FARGO BANK, N. A.
	 	 	 
	 	 	 
	 	By	/s/ JAMES B. SINGH
	 	 	JAMES B. SINGH,

      VICE PRESIDENT
	 	 	(Name and Title)
	 	 	 
	 	 	 
	 	By	/s/ A. R. CHAUDHARY
	 	 	A. R. CHAUDHARY, 

      VICE PRESIDENT
	 	 	(Name and Title)