Document:

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                                                                  EXHIBIT 10.48

                     [THE ROYAL BANK OF SCOTLAND LETTERHEAD]

To:      Inverness Medical Innovations, Inc. (the "PARENT GUARANTOR")
         as agent of each Borrower (as defined in the Senior Credit
         Agreement as defined below)

                                                            20th September 2002

Dear Sirs

CREDIT AGREEMENT DATED 20 DECEMBER 2001 MADE BETWEEN THE PARENT GUARANTOR,
INVERNESS MEDICAL SWITZERLAND GMBH, CERTAIN BANKS AND THE ROYAL BANK OF SCOTLAND
PLC AS LEAD ARRANGER, FACILITY AGENT, ISSUING BANK AND OVERDRAFT BANK (AS
AMENDED FROM TIME TO TIME, THE "SENIOR CREDIT AGREEMENT")

Unless otherwise defined herein capitalised terms used in this letter shall have
the meaning specified in the Senior Credit Agreement.

We, The Royal Bank of Scotland plc, write to you in our capacity as Facility
Agent for and on behalf of the Finance Parties.

The Parent Guarantor has requested pursuant to a letter dated 18 September 2002
that the Facility Agent consent to WL Acquisition Corp, a wholly owned
subsidiary of the Parent Guarantor acquiring the Wampole Laboratories division
of Medpointe, Inc. (the "ACQUISTION") and we are writing to confirm the terms
upon which the Facility Agent, on behalf of the Finance Parties, has consented
to the Acquisition.

1.       CONSENTS AND CONDITIONS

1.1      Notwithstanding Clause 14.3.8 (ACQUISITIONS) and Clause 14.3.5 (FEES)
         of the Senior Credit Agreement and subject to Clause 1.2 below, upon
         your countersignature of this letter the Facility Agent consents to the
         Acquisition and the payment of a maximum of US$1,000,000 on fees
         relating to the Acquisition.

1.2      The consents referred to in Clause 1.1 is subject to the following:

         1.2.1    Clause 1.1 (DEFINITIONS) of the Senior Facilities Agreement
                  shall be amended as follows:

                  (a)      in the second line of the definition of "GROUP" after
                           the words "IVC Group Company" inserting the words
                           "and, until the Wampole Security Date, each Wampole
                           Group Company";

                  (b)      after the definition "NEW EQUITY" inserting the
                           following:

                                    "NOTES" means the subordinated promissory
                                    notes issued by the Parent Guarantor
                                    pursuant to the Note Agreements.

<PAGE>

                                    "NOTE AGREEMENTS" means the Subordinated
                                    Note and Warrant Purchase Agreement and the
                                    Subordinated Note Purchase Agreement each
                                    dated on or about 20 September 2002 between
                                    the Parent and Note Holders.

                                    "NOTE HOLDERS" means the persons whose names
                                    are set out in Schedule 2 (NOTE HOLDERS) of
                                    the subordination agreement made between,
                                    among others, the Parent Guarantor, the Note
                                    Holders and the Security Trustee and shall
                                    include their respective assigns,
                                    transferees and successors whether immediate
                                    or derivative.

                  (c)      after the definition of "VENDOR" inserting the
                           following:

                                    ""WAMPOLE" means WL Acquisition Corp;

                                    "WAMPOLE GROUP" means Wampole and each of
                                    its Subsidiaries; and "WAMPOLE GROUP
                                    COMPANY" means any one of them;

                                    "WAMPOLE SECURITY" means a Group Guarantee
                                    and an Asset Security Document duly executed
                                    by each Wampole Group Company which is a
                                    Material Company and a Share Charge in
                                    respect of the entire issued share capital
                                    of each such company duly executed by any
                                    relevant Group Company together with such
                                    documentation in support thereof as the
                                    Security Trustee may reasonably require,
                                    including legal opinions (in form and
                                    substance satisfactory to the Security
                                    Trustee) from lawyers reasonably acceptable
                                    to the Security Trustee; and

                                    "WAMPOLE SECURITY DATE" means the date on
                                    which each Wampole Group Company delivers
                                    the Wampole Security to the Security
                                    Trustee."

         1.2.2    Clause 14.3 (NEGATIVE UNDERTAKINGS) shall be amended by
                  inserting after Clause 14.3.12 (ERISA) the following:

                  "14.3.13 PAYMENTS ON THE NOTES: in respect of the Parent
                           Guarantor only, repay or prepay, redeem or purchase
                           the Notes or pay any interest in respect of the Notes
                           provided that the Parent Guarantor may (i) pay in
                           common stock any amounts which are permitted to be
                           paid under the Notes in shares of Parent Guarantor
                           Common Stock (as such term is defined in the Notes),
                           US$0.001 par value per share; and (ii) pay in cash
                           (A) an aggregate amount of US$60,000 in respect of
                           interest accrued on the Notes up to and including 30
                           September 2002 and (B) interest on the Notes in
                           accordance with the terms of the Notes, so long as
                           (1) no Default has occurred and is continuing and (2)
                           the Parent Guarantor has not notified the Facility
                           Agent of any Potential Default pursuant to Clause
                           14.1.7."

                                      -2-

<PAGE>

         1.2.3    the execution by all the parties thereto of a subordination
                  agreement, in a form approved by us, subordinating the
                  subordinated notes and warrants and convertible notes used to
                  fund part of the purchase price of the Acquisition;

         1.2.4    no more than US$35,000,000 of cash from the Parent Guarantor's
                  consolidated balance sheet being used to pay the remaining
                  purchase price of the Acquisition. It is acknowledged by the
                  parties hereto that US$1,000,000 of the purchase price of the
                  Acquisition has been paid prior to the date of this letter;
                  and

         1.2.5    the Parent Guarantor prepaying an amount of at least
                  US$10,000,000 in prepayment of the Term Loan Facilities in
                  accordance with Clause 9.9.1 of the Senior Credit Agreement.

2.       UNDERTAKINGS

2.1      The Parent Guarantor undertakes to procure that, subject to any legal
         prohibitions or limitation on the giving of any of the Wampole Security
         (as defined above) either at all or within any time frame specified by
         the Facility Agent, on or prior to 31 October 2002 the Wampole Security
         will have been delivered to the Security Trustee.

2.2      Any breach of the undertaking set out in sub-clause 2.1 above shall be
         deemed to be a Default.

3.       EFFECTIVENESS OF THE SENIOR CREDIT AGREEMENT

         Subject to the consents set out in Clause 1.1 and save as expressly
         amended hereby, the Senior Credit Agreement shall remain in full force
         and effect in accordance with its terms and nothing contained herein
         shall prejudice any of the rights of the Finance Parties under the
         Financing Documents.

4.       COSTS AND EXPENSES

         The Parent Guarantor shall reimburse the Facility Agent from time to
         time for all costs and expenses (including reasonable legal fees and
         value added tax thereon) incurred by it in the preparation,
         negotiation, execution and enforcement of this letter and in connection
         with the preservation of its rights hereunder.

5.       SECURITY DOCUMENT

         The subordination agreement referred to in sub-paragraph 1.2.3 above
         shall be a Security Document.

6.       INCORPORATION OF TERMS

         The provisions of sub-clause 25.2 of Clause 25 (LAW AND JURISDICTION)
         of the Senior Credit Agreement shall be incorporated into this letter
         as if set out in full in this letter and as if references in such
         sub-clause to "this Agreement" or "the Financing Documents" are
         references to this letter.

                                      -3-

<PAGE>

7.       COUNTERPARTS

         This letter may be executed in any number of counterparts, and this has
         the same effect as if the signatures on the counterparts were on a
         single copy of this letter.

8.       GOVERNING LAW

         This letter is governed by and shall be construed in accordance with
         English law.

Yours faithfully

/s/ Gary McMillan
------------------------------
for and on behalf of
THE ROYAL BANK OF SCOTLAND PLC
for and on behalf of
the Finance Parties

We hereby accept and agree to the terms and conditions of this letter.

/s/ Paul T. Hempel
------------------------------
for and on behalf of
INVERNESS MEDICAL INNOVATIONS, INC.
for and on behalf of itself and
INVERNESS MEDICAL SWITZERLAND GMBH
Date 20.9.02

                                      -4-<PAGE>

                                                                  EXHIBIT 10.49

                     [THE ROYAL BANK OF SCOTLAND LETTERHEAD]

To:      Inverness Medical Innovations, Inc. (the "PARENT GUARANTOR")
         as agent of each Borrower (as defined in the Mezzanine Loan
         Agreement as defined below)

                                                            20th September 2002

Dear Sirs

MEZZANINE LOAN AGREEMENT DATED 20 DECEMBER 2001 MADE BETWEEN THE PARENT
GUARANTOR, INVERNESS MEDICAL SWITZERLAND GMBH, CERTAIN BANKS AND RBS MEZZANINE
LIMITED AS LEAD ARRANGER AND FACILITY AGENT (AS AMENDED FROM TIME TO TIME, THE
"MEZZANINE LOAN AGREEMENT")

Unless otherwise defined herein capitalised terms used in this letter shall have
the meaning specified in the Mezzanine Loan Agreement.

We, RBS Mezzanine Limited, write to you in our capacity as Facility Agent for
and on behalf of the Finance Parties.

The Parent Guarantor has requested pursuant to a letter dated 18 September 2002
that the Facility Agent consent to WL Acquisition Corp, a wholly owned
subsidiary of the Parent Guarantor acquiring the Wampole Laboratories division
of Medpointe, Inc. (the "ACQUISTION") and we are writing to confirm the terms
upon which the Facility Agent, on behalf of the Finance Parties, has consented
to the Acquisition.

1.       CONSENTS AND CONDITIONS

1.1      Notwithstanding Clause 12.3.8 (ACQUISITIONS) and Clause 12.3.5 (FEES)
         of the Mezzanine Loan Agreement and subject to Clause 1.2 below, upon
         your countersignature of this letter the Facility Agent consents to the
         Acquisition and the payment of a maximum of US$1,000,000 on fees
         relating to the Acquisition.

1.2      The consents referred to in Clause 1.1 is subject to the following:

         1.2.1    Clause 1.1 (DEFINITIONS) of the Mezzanine Loan Agreement shall
                  be amended as follows:

                  (a)      in the second line of the definition of "GROUP" after
                           the words "IVC Group Company" inserting the words
                           "and, until the Wampole Security Date, each Wampole
                           Group Company";

                  (b)      after the definition "NEW EQUITY" inserting the
                           following:

                                    "NOTES" means the subordinated promissory
                                    notes issued by the Parent Guarantor
                                    pursuant to the Note Agreements.

<PAGE>

                                    "NOTE AGREEMENTS" means the Subordinated
                                    Note and Warrant Purchase Agreement and the
                                    Subordinated Note Purchase Agreement each
                                    dated on or about 20 September 2002 between
                                    the Parent and Note Holders.

                                    "NOTE HOLDERS" means the persons whose names
                                    are set out in Schedule 2 (NOTE HOLDERS) of
                                    the subordination agreement dated on or
                                    about 20 September 2002 made between, among
                                    others, the Parent Guarantor, the Note
                                    Holders and the Security Trustee and shall
                                    include their respective assigns,
                                    transferees and successors whether immediate
                                    or derivative.

                  (c)      after the definition of "VENDOR" inserting the
                           following:

                                    ""WAMPOLE" means WL Acquisition Corp;

                                    "WAMPOLE GROUP" means Wampole and each of
                                    its Subsidiaries; and "WAMPOLE GROUP
                                    COMPANY" means any one of them;

                                    "WAMPOLE SECURITY" means a Group Guarantee
                                    and an Asset Security Document duly executed
                                    by each Wampole Group Company which is a
                                    Material Company and a Share Charge in
                                    respect of the entire issued share capital
                                    of each such company duly executed by any
                                    relevant Group Company together with such
                                    documentation in support thereof as the
                                    Security Trustee may reasonably require,
                                    including legal opinions (in form and
                                    substance satisfactory to the Security
                                    Trustee) from lawyers reasonably acceptable
                                    to the Security Trustee; and

                                    "WAMPOLE SECURITY DATE" means the date on
                                    which each Wampole Group Company delivers
                                    the Wampole Security to the Security
                                    Trustee."

         1.2.2    Clause 14.3 (NEGATIVE UNDERTAKINGS) shall be amended by
                  inserting after Clause 14.3.12 (ERISA) the following:

                  "14.3.13 PAYMENTS ON THE NOTES: in respect of the Parent
                           Guarantor only, repay or prepay, redeem or purchase
                           the Notes or pay any interest in respect of the Notes
                           provided that the Parent Guarantor may (i) pay in
                           common stock any amounts which are permitted to be
                           paid under the Notes in shares of Parent Guarantor
                           Common Stock (as such term is defined in the Notes),
                           US$0.001 par value per share; and (ii) pay in cash
                           (A) an aggregate amount of US$60,000 in respect of
                           interest accrued on the Notes up to and including 30
                           September 2002 and (B) interest on the Notes in
                           accordance with the terms of the Notes, so long as
                           (1) no Default has occurred and is continuing and (2)
                           the Parent Guarantor has not notified the Facility
                           Agent of any Potential Default pursuant to Clause
                           12.1.7."

                                      -2-

<PAGE>

         1.2.3    the execution by all the parties thereto of a subordination
                  agreement, in a form approved by us, subordinating the
                  subordinated notes and warrants and convertible notes used to
                  fund part of the purchase price of the Acquisition;

         1.2.4    no more than US$35,000,000 of cash from the Parent Guarantor's
                  consolidated balance sheet being used to pay the remaining
                  purchase price of the Acquisition. It is acknowledged by the
                  parties hereto that US$1,000,000 of the purchase price of the
                  Acquisition has been paid prior to the date of this letter;
                  and

         1.2.5    the Parent Guarantor prepaying an amount of at least
                  US$10,000,000 in prepayment of the Senior Term Loans in
                  accordance with Clause 9.9.1 of the Senior Credit Agreement.

2.       UNDERTAKINGS

2.1      The Parent Guarantor undertakes to procure that, subject to any legal
         prohibitions or limitation on the giving of any of the Wampole Security
         (as defined above) either at all or within any time frame specified by
         the Facility Agent, on or prior to 31 October 2002 the Wampole Security
         will have been delivered to the Security Trustee.

2.2      Any breach of the undertaking set out in sub-clause 2.1 above shall be
         deemed to be a Default.

3.       EFFECTIVENESS OF THE MEZZANINE LOAN AGREEMENT

         Subject to the consents set out in Clause 1.1 and save as expressly
         amended hereby, the Mezzanine Loan Agreement shall remain in full force
         and effect in accordance with its terms and nothing contained herein
         shall prejudice any of the rights of the Finance Parties under the
         Financing Documents.

4.       COSTS AND EXPENSES

         The Parent Guarantor shall reimburse the Facility Agent from time to
         time for all costs and expenses (including reasonable legal fees and
         value added tax thereon) incurred by it in the preparation,
         negotiation, execution and enforcement of this letter and in connection
         with the preservation of its rights hereunder.

5.       SECURITY DOCUMENT

         The subordination agreement referred to in sub-paragraph 1.2.3 above
         shall be a Security Document.

6.       INCORPORATION OF TERMS

         The provisions of sub-clause 23.2 of Clause 23 (LAW AND JURISDICTION)
         of the Mezzanine Loan Agreement shall be incorporated into this letter
         as if set out in full in this letter and as if references in such
         sub-clause to "this Agreement" or "the Financing Documents" are
         references to this letter.

                                      -3-

<PAGE>

7.       COUNTERPARTS

         This letter may be executed in any number of counterparts, and this has
         the same effect as if the signatures on the counterparts were on a
         single copy of this letter.

8.       GOVERNING LAW

         This letter is governed by and shall be construed in accordance with
         English law.

Yours faithfully

/s/ Gary McMillan
------------------------------------
for and on behalf of
RBS MEZZANINE LIMITED
for and on behalf of
the Finance Parties

We hereby accept and agree to the terms and conditions of this letter.

/s/ Paul T. Hempel
------------------------------------
for and on behalf of
INVERNESS MEDICAL INNOVATIONS, INC.
for and on behalf of itself and
INVERNESS MEDICAL SWITZERLAND GMBH
Date 20.9.02

                                      -4-

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