TD Tower Branch Commercial Banking Centre 2nd Floor, TD Tower

 TD Xxxxx Xxxxxx 

 Xxxxxxxxxx Xxxxxxx Xxxxxx 

 0xx Xxxxx, TD Tower 

 000 Xxxxxxx Xxxxxx X., Xxxxxxx Xxxxxx 

 XX Xxx 00000 

Xxxxxxxxx, XX X0X 0X0 

Telephone No. : (000) 000-0000 

Fax No. : (000) 000-0000 

December 13, 2004

Response Biomedical Corp.
0000 Xxxxxxxx Xxx
Xxxxxxx, X.X.
X0X 0X0

Attn: Xx. Xxxx Xxxxxx and Xx. Xxxxxx Xxxx,

Dear Sirs,

DEMAND OPERATING FACILITY AGREEMENT AMENDMENT

This Amending
Agreement between:	The Toronto-Dominion Bank (the "Bank"), through its branch, in
	and
Borrower's Legal Name:	(herein called the "Borrower")
Borrower's Address:
Whereas:	The Bank has agreed to establish a revolving demand credit facility (the "Facility") as per the Demand Operating Facility Agreement dated June 16, 2004 which together with Schedule "A" of the Demand Operating Facility Agreement comprise the "Agreement".

In consideration of the Bank continuing to make the Facility available, the Borrower hereby agrees with the Bank to the following amendments to the terms and conditions of the Agreement:

AVAILABILITY
OF THE FACILITY	The Borrower acknowledges that the Facility is uncommitted and is not automatically available upon satisfaction of the terms and conditions, including without limitation the Representations & Warranties, Positive Covenants, Negative Covenants, or Financial Covenants set out herein.
	The Bank can demand repayment and/or cancel the availability of the Facility at any time.

REPAYMENT	The Borrower agrees to repay the Bank on demand. If the Bank demands repayment, the Borrower will pay to the Bank all amounts outstanding under the Facility, including without limitation, as applicable, the amount of all unmatured B/As and the amount of all drawn and undrawn L/Gs and L/Cs. All costs to the Bank and all loss suffered by the Bank in re-employing the amounts so repaid will be paid by the Borrower.
	In absence of prior demand, Facility #1 is to be repaid in full on or before December 15, 2005.
SECURITY	The Borrower will provide the following additional security to support all of its present and future indebtedness and liability to the Bank including without limitation indebtedness and liability under guarantees, foreign exchange contracts, cash management products, and derivative contracts:
		Irrevocable Standby Letter of Credit - US$1,000,000 issued by Bank Xxxxxxx of Basel Switzerland  in favour of TD Bank, Global Trade Finance and Financial Institutions, expiring December 30,  2005.
	All persons and entities required to provide a guarantee shall be referred to herein individually as a "Guarantor" and/or "Surety" and collectively as the "Guarantors". All of the above security and guarantees and any previously provided Bank Security shall be referred to collectively in this Agreement as "Bank Security". The security will be registered in first position, and will be on the Bank's standard form, supported by resolutions and solicitor's opinion, all acceptable to the Bank.
SCHEDULE "A"
TERMS AND
CONDITIONS	Schedule "A" sets out the Standard Terms and Conditions ("Standard Terms and Conditions") which are applicable to the Borrower and which apply to this Facility. The Standard Terms and Conditions, including the defined terms set out therein, form part of this Agreement, unless this letter states specifically that one or more of the Standard Terms and Conditions do not apply or are modified.

Unless otherwise stated, the amendments outlined above are in addition to the Terms and Conditions of the existing Agreement. All other terms and conditions remain unchanged. We ask that you acknowledge your agreement to these amendments by signing and returning the attached duplicate copy of this Amending Agreement to the undersigned. The amendments will not come into force unless the duplicate of this Amending Agreement is received by the Bank on or before December 22, 2004.

Yours truly,

THE TORONTO-DOMINION BANK

/s/ XXXX XXXXXXXXXX	/s/ XXXX XXXX
Xxxx Xxxxxxxxxx	Xxxx Xxxx
Relationship Manager	Manager, Commercial Credit

The foregoing is acknowledged and accepted by the Borrower. The following persons have the capacity to bind the Borrower.

Borrower's authorized officers or representatives:

/s/ XXXXXX XXXX	/s/ XXXXX XXXXXXXX
Signature	Signature
XXXXXX XXXX, cfo	XXXXX XXXXXXXX, EXECUTIVE VP, DIRECTOR
Print Name & Position	Print Name & Position
DEC.13, 0000	00-00-00
Date:	Date: