<Page>

                                                                     EXHIBIT 3.4

                                    BYLAWS OF

                       3-GEN DIAGNOSTIC LABORATORIES, INC.

                                ARTICLE I OFFICES

     The principal office of the corporation shall be located at Holladay, UT.

                             ARTICLE II SHAREHOLDERS

SECTION 1. ANNUAL MEETINGS
The annual meeting of the shareholders shall be held on the
                        1
___________________________________
Number of Week     Day of Week
of the month of July in each year, beginning with the year 1997 at the hour of
_____ o'clock __m. for the purpose of electing Directors and for the
transaction of such other business as may come before the meeting. If the day
fixed for the annual meeting shall be a legal holiday in the State of
_______________, such meeting shall be held on the next succeeding business day.
If the election of Directors shall not be held on the day designated herein, for
any annual meeting of the shareholders, or at any adjournment thereof, the Board
of Directors shall cause the election to be held at a special meeting of the
shareholders as soon thereafter as conveniently may be.

SECTION 2 SPECIAL MEETINGS
Special meetings of the shareholders, for any purpose or purposes, unless
otherwise prescribed by statute, may be called by the President or by the Board
of Directors and shall be called by the President at the request of the holders
if not less than one-tenth of all the outstanding shares of the corporation
entitled to vote are at the meeting.

SECTION 3 PLACE OF MEETING
The Board of Directors may designate any place, either within or without the
State of Utah, as the place of meeting for any annual or special meeting of
shareholders. If no designation is made, the place of meeting shall be the
principal office of the corporation.

SECTION 4 NOTICE OF MEETING
Written or printed notice stating the place, day and hour of the meeting and, in
case of a special meeting, the purpose or purposes for which the meeting is
called, shall be delivered not less than ten or more than fifty days before the
date of the meeting, either personally or by mail, by or at the direction of the
President, or the Secretary or the officer or persons calling the meeting, to
each shareholder of record entitled to vote at such, meeting. If mailed, such
notice shall be deemed to be delivered when deposited in the United States mail,
addressed to the shareholder at the Shareholder's address as it appear on the
stock transfer books of the corporation, with postage thereon prepaid.

SECTION 5 QUORUM
A majority of the outstanding shares of the corporation entitled to vote,
represented in person or by

                                        1
<Page>

proxy, shall constitute a quorum at a meeting of shareholders. If less than a
majority of the outstanding shares are represented at a meeting majority of the
shares so represented may adjourn the meeting from time to time without further
notice. At such adjourned meeting, at which a quorum shall be present or
represented, any business may be transacted which might have been transacted at
the meeting as originally notified.

SECTION 6 PROXIES
At all meetings of shareholders, a shareholder may vote by proxy executed in
writing by the shareholder or by the Shareholder's duly authorized attorney in
fact. Such proxy shall be filed with the Secretary of the corporation before or
at the time of the meeting. No proxy shall be valid after eleven months from the
date of its execution, unless otherwise provided in the proxy.

SECTION 7 VOTING OF SHARES
Subject to the provisions of Section 9, each outstanding share entitled to vote
shall be entitled to one vote upon each matter submitted to a vote at a meeting
of shareholders.

SECTION 8 PREEMPTIVE RIGHTS
Each holder of shares in this corporation shall have the first right to purchase
shares (and securities convertible into shares) of this corporation that may be
from time to time issued (whether or not presently authorized), including shares
from the treasury of this corporation, in the ratio that the number of shares
held by said holder at the time of issue bears to the total number of shares
outstanding, exclusive of treasury shares. This right shall be deemed waived by
any shareholder who does not exercise it and pays for the shares preempted
within thirty (30) days of receipt of a notice in writing from the corporation
stating the prices, terms and conditions of the issue of shares and inviting
said holder to exercise his preemptive rights.

SECTION 9 CUMULATIVE VOTING
Every shareholder entitled to vote at each election of Directors shall have the
right to accumulate their votes by giving one candidate as many votes as the
number of the Directors to be elected multiplied by the number of their shares
shall equal, or by distributing such votes on the same principal among any
number of such candidates.

SECTION 10 INFORMAL ACTION BY SHAREHOLDER
Any action required to be taken at a meeting of the shareholders, or any other
action which may be taken at a meeting of the shareholders, may be taken without
a meeting of a consent in writing, setting forth the action so taken, shall be
signed by all of the shareholders entitled to vote with respect to the subject
matter thereof.

                         ARTICLE III BOARD OF DIRECTORS

                                        2
<Page>

SECTION 1 GENERAL POWERS
The business and affairs of the corporation shall be managed by its Board of
Directors.

SECTION 2 NUMBER TENURE, AND QUALIFICATIONS
The number of Directors of the corporation shall be at least two but not more
than seven. Each director shall hold office until the next annual meeting of
shareholders and until the Director's successor shall have been elected and
qualified.

SECTION 3 REGULAR MEETINGS
A regular meeting of the Board of Directors shall be held without other notice
than this by-law immediately after, and at the same place as, the annual meeting
of shareholders. The Board of Directors may provide, by resolution, the time and
place, either within or without the State of Utah, for the holding of additional
regular meetings without other notice than such resolution.

SECTION 4 SPECIAL MEETINGS
Special meetings of the Board of Directors may be called by or at the request of
the President or any two Directors. The person or persons authorized to call
special meetings of the Board of Directors may fix any place either within or
without the State of Utah, as the place for holding any special meeting of the
Board of Directors called by them.

SECTION 5 NOTICE
Notice of any special meeting shall be given at least four days previously
thereto by written notice delivered personally or mailed to each Director at
their customary business address. If mailed, such notice shall be deemed to be
delivered when deposited in the United States Mail so addressed, with postage
thereon prepaid. Any Director may waive notice of any meeting. The attendance of
a Director at a meeting shall constitute a waiver of notice of such meeting,
except where a Director attends a meeting for the express purpose of objecting
to the transaction, of any business because the meeting is not lawfully called
or convened. Neither the business to be transacted at, nor the purpose of, any
regular or special meeting of the Board of Directors need be specified in the
notice or waiver of notice of such meeting.

SECTION 6 QUORUM
A majority of the number of Directors fixed by Section 2 of this Article III
shall constitute a quorum for the transaction of business at any meeting of the
Board of Directors, but if less than such majority is present at a meeting, a
majority of the Directors present may adjourn the meeting from time to time
without further notice.

SECTION 7 MANNER OF ACTING
The act of the majority of the Directors present at a meeting at which a quorum
is present shall be the act of the Board of Directors.

SECTION 8 VACANCIES
Any vacancy occurring in the Board of Directors may be filled by the affirmative
vote of a majority of the remaining Directors though less than a quorum of the
Board of Directors. A Director sleeted to fill a vacancy shall be elected for
the unexpected term of the predecessor in office.

                                        3
<Page>

SECTION 9 COMPENSATION
By resolution of the Board of Directors, the Directors may be paid their
expenses, if any, for attendance at each meeting of the Board of Directors, and
may be paid a fixed sum for attendance at each meeting of the Board of
Directors. No such payment shall preclude any director from serving the
corporation any other capacity and receiving compensation therefor.

SECTION 10 PRESUMPTION OF ASSENT
A Director of the corporation who is present at a meeting of the Board of
Directors, at which action on any corporate matter is taken shall be presumed to
assent to the action taken unless Director's dissent shall be entered in the
minutes, of the meeting or unless the Director shall file a 'written dissent to
such action with the person acting as the Secretary of the meeting before the
adjournment thereof, or shall forward such dissent by registered mail to the
Secretary of the corporation immediately after the adjournment of the meeting.
Such right to dissent shall not apply to a Director who voted in favor of such
action.

SECTION 11 EXECUTIVE COMMITTEE
The Board of Directors, by resolution adopted by the majority of the Directors
fixed by the by-laws, may designate a committee of not less than two Directors
which committee, in absence of a resolution of the Board of Directors limiting
or restricting its authority shall have and may exercise all of the authority of
the Board of Directors in the management of all business and affairs of the
corporation, except the Executive Committee may not fill vacancies in the Board
of Directors or amend, these by-laws. The Board of Directors may at any time
remove any member of the Executing Committee with or without cause and may
terminate or in any way in its sole discretion limit or restrict the authority
of the Executive Committee. The Committee shall keep a record of its proceedings
and report such proceedings to the Board of Directors.

                               ARTICLE IV OFFICERS

SECTION 1 NUMBER
The officers of the corporation shall be a President, one of the Vice Presidents
(the number thereof, if any, to be determined by the Board of Directors), a
Secretary, and a Treasurer, each of who shall be elected by the Board of
Directors. Any, two or more officers may be held by the same person, except the
offices of President and Secretary.

SECTION 2 ELECTION AND TERM OF OFFICE
The officers of the corporation to be elected by the Board of Directors shall be
elected annually by the Board of Directors at the first meeting of the Board of
Directors held after each annual meeting of the shareholders. If the election of
officers shall not be held at such meeting, such election shall be held as soon
thereafter as conveniently may be. Each officer shall hold office until a
successor shall have been duly elected and shall have qualified or until the
Officer's death or until the Officer shall resign or shall have been removed in
the manner hereinafter provided.

SECTION 3 REMOVAL
Any officer or agent elected or appointed by the Board of Directors may be
removed by the Board of Directors, whenever in its judgment the best interests
of the corporation would be served thereby, but such removal shall be without
prejudice to the contract rights, if any, of the person so removed.

                                        4
<Page>

Election or appointment of an officer or agent shall not of itself create
contract rights.

SECTION 4 VACANCIES
A vacancy in any office because of death, resignation removal, disqualification
or otherwise, may be fil1ed by the Board of Directors for the unexpired portion
of the term.

SECTION 5 PRESIDENT
The President shall be the principal executive officer of the corporation and,
subject to the control of the Board of Directors, shall in general supervise and
control all of the business and affairs of the corporation. The President shall,
when present, preside at all meetings of the shareholders and of the Board of
Directors. The President may sign, with the Secretary or any other proper
officer of the corporation thereunto authorized by the Board of Directors,
certificates for shares of the corporation, and in general shall perform all
duties incident to the office of President and such other duties as may be
prescribed by the Board of Directors from time to time.

SECTION 6 THE VICE PRESIDENT
In the absence of the President or in the event of the President's death,
inability or refusal to act, the Vice President (or in the event there be more
than one Vice President, the Vice Presidents in the order designated at the time
of their election, or in the absence of any designation, then in the order of
their election) shall perform the duties of the President, and when so acting
shall have all the powers of and be subject to all the restrictions upon the
President. Any Vice President may sign, with the Secretary or an Assistant
Secretary, certificates for shares of the corporation; and shall perform such
other duties as from time to time may be assigned to the Vice President by the
President or by the Board of Directors.

SECTION 7 THE SECRETARY
The Secretary shall: (a) keep the minutes of the shareholders' and of the Board
of Directors' meetings in one or more books provided for the purpose; (b) see
that all notices are duly given in accordance with the provisions of these
by-laws or as required by law; (c) be custodian of the corporate records and of
the seal of the corporation and see that the seal of which on behalf of the
corporation under its seal is duly authorized; (d) keep a register of the post
office address of each shareholder which shall be furnished to the Secretary by
such shareholder; (e) sign with the President, or a Vice President, certificates
for shares of the corporation, the issuance of which shall have been authorized
by resolution of the Board of Directors; (f) have general charge of the stock
transfer books of the corporation; and (g) in general perform all duties
incident to the office of Secretary and such other duties as from time to time
may be assigned to the Secretary by the President or by the Board of Directors.

SECTION 8 THE TREASURER
The Treasurer shall (a) have charge and custody of and be responsible for all
funds and securities of the corporation; (b) receive and give receipts for
moneys due and payable to the corporation from any source whatsoever, and
deposit all such moneys in the name of the corporation in such banks, trust

                                        5
<Page>

companies or other depositories as shall be selected in accordance with the
provisions of Article V of these by-laws and (c) in general perform all of the
duties incident to the office of the Treasurer and such other duties as from
time to time may be assigned to Treasurer by the President or by the Board of
Directors.

SECTION 9 SALARIES
The salaries of the officers shall be fixed from time to time by the Board of
Directors and no officer shall be prevented from receiving such salary by reason
of the fact that the officer is also a Director of the corporation.

                ARTICLE V CONTRACTS, LOANS, CHECKS, AND DEPOSITS

SECTION 1 CONTRACTS
The Board of Directors may authorize any officer or officers, agent or agents,
to enter into any contract, to execute and deliver any instrument in the name of
and on behalf of the corporation, and such authority may be general or confined
to specific instances.

SECTION 2 LOANS
No loans shall be contracted on behalf of the corporation and no evidences of
indebtedness shall be issued in its name unless authorized by a resolution of
the Board of Directors. Such authority may be general or confined to specific
instances.

SECTIONS 3 CHECKS, DRAFTS, ETC.
All checks, drafts, or other orders for the payment of money, notes or other
evidences of indebtedness issued in the name of the corporation shall be signed
by such officer or officers, agent or agents, of the corporation and in such
manner as shall from time to time be determined by resolution of the Board of
Directors.

SECTION 4 DEPOSITS
All funds of the corporation otherwise employed shall be deposited from time to
time to the credit of the corporation in such banks, trust companies or other
depositories as the Board of Directors may select.

              ARTICLE VI CERTIFICATES FOR SHARES AND THEIR TRANSFER

SECTION 1 CERTIFICATES FOR SHARES
Certificates representing shares of the corporation shall be in such form, as
shall be determined by the

                                        6
<Page>

Board of Directors. Such certificates shall be signed by the President or a
Vice President and by the Secretary, or an Assistant Secretary. All
certificates for shares shall be consecutively numbered or otherwise
identified. The name and address of the person to whom the shares represented
thereby are issued, with the number of shares and date of issue, shall be
entered on the stock transfer books of the corporation. All certificates
surrendered to the corporation for transfer shall be canceled and no
certificates shall be issued until the former certificate for a like number
of shares shall have been surrendered and canceled, except that in case of a
lost, destroyed or mutilated certificate, a new one may be issued therefor
upon such terms and indemnity to the corporation as the Board of Directors
may prescribe.

SECTION 2 TRANSFER OF SHARES
Transfer of shares of the corporation shall be made only on the stock transfer
books of the corporation by the holder of record thereof or by a legal
representative, who shall furnish proper evidence of authority to transfer, or
by an attorney thereunto authorized by power of attorney duly executed and filed
with the Secretary of the corporation, and on surrender for cancellation of the
certificate for such shares. The person in whose name shares stand on the books
of the corporation shall be deemed by the corporation to be the owner thereof
for all purposes.

                             ARTICLE VII FISCAL YEAR

The fiscal year of the corporation shall begin on the first day of January and
end on the 31 day of December in the year _____.

                              ARTICLE VIII DIVIDENDS

The Board of Directors may from time to time declare, and the corporation may
pay, dividends on its outstanding shares in the manner and upon the terms and
conditions provided by law.

                                 ARTICLE IX SEAL

The Board of Directors shall provide a corporate seal which shall be circular in
form and shall have inscribed thereon the name of the corporation and conditions
provided by law.

                           ARTICLE X WAIVER OF NOTICE

Whenever any notice is required to be given to any shareholder or director of
the corporation ender the provisions of these by-laws or under the provisions of
the articles of incorporation or under the provisions of the
________________________,
Business Corporation Act

a waiver thereof in writing, signed by the person or persons
entitled to such notice, whether before or after the time stated therein, shall
be deemed equivalent to the giving of such notice.

                              ARTICLE XI AMENDMENTS

These by-laws may be altered, amended or repealed and new by-laws may be adopted
by unanimous vote of the Board of Directors at any regular of special meeting of
the Board of Directors, or by affirmative vote of two-thirds of the outstanding
shares.

                                        7