MOLECULAR DIAGNOSTICS, INC.

                               OFFER TO EXCHANGE
             800,000 SHARES OF SERIES E CONVERTIBLE PREFERRED STOCK
                                   FOR UP TO
                       20,000,000 SHARES OF COMMON STOCK

TO OUR CLIENTS:

     Enclosed for your consideration is an Offering Circular, dated November 19,
2001 (the "Offering Circular"), and the related Letter of Transmittal (the
"Letter of Transmittal"), relating to the offer to exchange (the "Exchange
Offer") 1/25 (one twenty-fifth) of a share of Series E convertible preferred
stock, par value $0.001 per share, of Molecular Diagnostics, Inc. ("Molecular
Diagnostics") for each share of common stock, par value $0.001, per share, of
Molecular Diagnostics currently outstanding. Subject to the terms and conditions
of the Exchange Offer, Molecular Diagnostics will issue 800,000 shares of Series
E convertible preferred stock in exchange for up to 20,000,000 shares of common
stock representing approximately 56% of the outstanding common stock as of
November 16, 2001, that, in each case, are properly tendered and not withdrawn
prior to the expiration of the Exchange Offer. If more than 20,000,000 shares of
common stock are tendered, Molecular Diagnostics will purchase from each
tendering holder of common stock an amount based on the proportion of common
stock tendered by that holder to all common stock tendered. For a more detailed
description of the Series E convertible preferred stock Molecular Diagnostics is
proposing to issue in the Exchange Offer, please see the section of the Offering
Circular entitled "Description of Series E Convertible Preferred Stock."
Molecular Diagnostics reserves the right to extend or terminate the Exchange
Offer, in its sole and absolute discretion, which may be for any or no reason,
and to otherwise amend the Exchange Offer in any respect. The Exchange Offer is
open to all holders of common stock and is subject to customary conditions.
Subject to applicable securities laws and the terms set forth in the Offering
Circular, Molecular Diagnostics reserves the right to waive any and all
conditions to the Exchange Offer.

     These materials are being forwarded to you as the beneficial owner of
common stock held by us for your account but not registered in your name. A
TENDER OF THE COMMON STOCK MAY ONLY BE MADE BY US AS THE HOLDER OF RECORD AND
PURSUANT TO YOUR INSTRUCTIONS.

     Accordingly, we request instructions as to whether you wish us to tender on
your behalf any common stock held by us for your account, pursuant to the terms
and conditions set forth in the enclosed Offering Circular and Letter of
Transmittal.

     Your instructions should be forwarded to us as promptly as possible in
order to permit us to tender any common stock on your behalf in accordance with
the provisions of the Exchange Offer. The Exchange Offer will expire at 5:00
p.m., New York City time, on December 19, 2001, unless extended.

     Molecular Diagnostics may, in its sole and absolute discretion, extend the
Exchange Offer. Any common stock tendered pursuant to the Exchange Offer may be
withdrawn at any time before the expiration of the Exchange Offer or at any time
after January 18, 2002 if Molecular Diagnostics has not accepted the tendered
common stock for exchange by that date.

     Your attention is directed to the following:

     1. The Exchange Offer is for up to 20,000,000 outstanding shares of common
        stock.

     2. The Exchange Offer is subject to certain conditions set forth in the
        Offering Circular under the title "The Exchange Offer -- Conditions to
        the Exchange Offer."

     3. Any transfer taxes incident to the transfer of common stock from the
        holder to Molecular Diagnostics will be paid by Molecular Diagnostics,
        except as otherwise provided in the Letter of Transmittal.

     4. The Exchange Offer expires at 5:00 p.m., New York City time, on December
        19, 2001, unless extended. Molecular Diagnostics, in its sole and
        absolute discretion, may extend the Exchange Offer.

     If you wish to have us tender any common stock, please so instruct us by
completing, executing and returning to us the instruction form on the back of
this letter. THE LETTER OF TRANSMITTAL IS FURNISHED TO YOU FOR INFORMATION ONLY
AND MAY NOT BE USED DIRECTLY BY YOU TO TENDER COMMON STOCK.

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                INSTRUCTIONS WITH RESPECT TO THE EXCHANGE OFFER

     The undersigned acknowledge(s) receipt of your letter and the enclosed
materials referred to therein relating to the Exchange Offer made by Molecular
Diagnostics, Inc. with respect to the common stock.

     This will instruct you to tender the common stock held by you for the
account of the undersigned, subject to the terms and conditions set forth in the
Offering Circular and the related Letter of Transmittal.

     Please tender common stock held by you for my account as indicated below:

     Common Stock:
     ----------------------- (number of shares of common stock)

     [ ] Please do not tender any common stock held by you for my account.

     [ ] Not applicable.

     Dated:           , 2001

Signature(s):
             ------------------------------------------------------------------

Print Name(s) here:
                   ------------------------------------------------------------

(Print Address(es)):
                    -----------------------------------------------------------

(Area Code and Telephone Number(s)):
                                    -------------------------------------------

(Tax Identification or Social Security Number(s)):
                                                  -----------------------------

     NONE OF THE COMMON STOCK HELD BY US FOR YOUR ACCOUNT WILL BE TENDERED
UNLESS WE RECEIVE WRITTEN INSTRUCTIONS FROM YOU TO DO SO. UNLESS A SPECIFIC
CONTRARY INSTRUCTION IS GIVEN IN THE SPACE PROVIDED, YOUR SIGNATURE(S) HEREON
SHALL CONSTITUTE AN INSTRUCTION TO US TO TENDER ALL THE COMMON STOCK HELD BY US
FOR YOUR ACCOUNT.

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