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                                                                     Exhibit 5.1

                       [Letterhead of Goodwin Procter LLP]


April 25, 2003


Inverness Medical Innovations, Inc.
51 Sawyer Road, Suite 200
Waltham, MA 02453

Re:  PRE-EFFECTIVE AMENDMENT NO. 1 TO REGISTRATION STATEMENT ON FORM S-4

Ladies and Gentlemen:

In accordance with Item 601(b)(5) of Regulation S-K, we are furnishing this
opinion to you in our capacity as counsel to Inverness Medical Innovations,
Inc. (the "Company") in connection with the preparation of an amendment to a
registration statement on Form S-4 (the "Amended Registration Statement"), to
be filed with the Securities and Exchange Commission under the Securities Act
of 1933, as amended (the "Securities Act"), on or about the date hereof. The
Amended Registration Statement relates to up to 1,900,663 shares (the
"Shares") of the Company's common stock, par value $.001 per share (the
"Common Stock"), to be issued to the shareholders of Ostex International,
Inc. ("Ostex") in connection with the merger of Geras Acquisition Corp.
("Geras"), a Washington corporation and wholly owned subsidiary of the
Company, with and into Ostex. We understand the Shares are to be offered and
sold in the manner described in the Amended Registration Statement.

As counsel for the Company, we have examined copies of the following
documents: (i) the Amended Registration Statement and the exhibits thereto;
(ii) the Agreement and Plan of Merger, dated as of September 6, 2002, by and
among the Company, Geras and Ostex (the "Agreement"); (iii) the Amendment to
Agreement and Plan of Merger, dated as of February 18, 2003, by and among the
Company, Geras and Ostex (the "Amendment"); (iv) the Company's Certificate of
Incorporation and By-laws, each as amended to date and presently in effect;
(v) such records of the corporate proceedings of the Company as we deemed
material; and (vi) such records, certificates and other documents of the
Company as we have deemed necessary or appropriate for the purposes of this
opinion. In our examination, we have assumed the genuineness of all
signatures, the legal capacity of natural persons, the authenticity of all
documents submitted to us as certified, photostatic or facsimile copies, the
authenticity of the originals of such copies and the authenticity of
telephonic confirmations of public officials and others. As to facts material
to our opinion, we have relied upon certificates or telephonic confirmations
of public officials and certificates, documents, statements and other
information of the Company or representatives or officers thereof.

We are attorneys admitted to practice in The Commonwealth of Massachusetts. We
express no opinion concerning the laws of any jurisdictions other than the
federal laws of the United States of America, The Commonwealth of Massachusetts
and the Delaware General Corporation Law

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Inverness Medical Innovations, Inc.
April 25, 2003
Page 2


(which includes applicable provisions of the Delaware Constitution and reported
judicial decisions interpreting the Delaware General Corporation Law and the
Delaware Constitution).

Based on the foregoing, we are of the opinion that the Shares have been duly
authorized and, when the Amended Registration Statement relating to the
Shares is declared effective under the Securities Act and the Shares have
been issued in exchange for the shares of common stock of Ostex as
contemplated in the Agreement, as amended by the Amendment, the Shares will
be validly issued, fully paid and non-assessable by the Company.

This opinion shall be interpreted in accordance with the Legal Opinion
Principles issued by the Committee on Legal Opinions of the American Bar
Association's Business Law Section as published in 53 Business Lawyer 831
(May 1998).

The opinions expressed herein are being furnished to you solely for your
benefit in connection with the Registration Statement and may not be used or
relied upon by you for any other purpose. This opinion is given as of the
date first set forth above, and we assume no obligation to update this
opinion after such date. We hereby consent to the inclusion of this opinion
as an exhibit to the Amended Registration Statement and to the reference to
our firm under the heading "Legal Matters" in the Company's proxy
statement/prospectus which is part of the Amended Registration Statement.

Very truly yours,

/s/ Goodwin Procter LLP

GOODWIN PROCTER LLP