Exhibit
10.6


AMENDED AND RESTATED

QUIDEL CORPORATION

(formerly Monoclonal Antibodies, Inc.)

1983 EMPLOYEE STOCK PURCHASE PLAN

(as amended March 20, 2007)


The following constitute the provisions of the 1983 Employee Stock
Purchase Plan (herein called the “Plan”) of Quidel Corporation, a Delaware
corporation (herein called the “Company”).


1.     Purpose.  The purpose of the Plan is to provide
employees of the Company and its Designated Subsidiaries with an opportunity to
purchase Common Stock of the Company through accumulated payroll
deductions.  It is the intention of the
Company to have the Plan qualify as an “Employee Stock Purchase Plan” under
Section 423 of the Internal Revenue Code of 1986, as amended.  The provisions of the Plan shall,
accordingly, be construed so as to extend and limit participation in a manner
consistent with the requirements of that section of the Code.


2.     Definitions.


(a)   “Board” shall mean the Board of Directors of the Company.


(b)   “Code” shall mean the Internal Revenue Code of 1986, as
amended.


(c)   “Common Stock” shall mean the Common Stock, no par value, of
the Company.


(d)   “Company” shall mean Quidel Corporation, a Delaware
corporation.


(e)   “Compensation” shall mean all regular straight time earnings,
payments or overtime, shift premium, incentive compensation, incentive
payments, bonuses and commissions (except to the extent that the exclusion of
any such items for all participants is specifically directed by the Board or
its committee).


(f)    “Designated Subsidiaries” shall mean the Subsidiaries which
have been designated by the Board from time to time in its sole discretion as
eligible to participate in the Plan.


(g)   “Employee” shall mean any person, including an officer, who
is customarily employed for at least twenty (20) hours per week and more than
five (5) months in a calendar year by the Company or one of its Designated
Subsidiaries.


(h)   “Exercise Date” shall mean the last day of each offering
period of the Plan.


(i)    “Offering Date” shall mean the first day of each offering
period of the Plan.


(j)    “Plan” shall mean this Employee Stock Purchase Plan.


(k)   “Subsidiary” shall mean a corporation, domestic or foreign,
of which not less than 50% of the voting shares are held by the Company or a
Subsidiary, whether or not such corporation flow exists or is hereafter
organized or acquired by the Company or a Subsidiary.


3.     Eligibility.


(a)   Any Employee as defined in
paragraph 2 who shall be employed by the Company on the date his participation
in the Plan is effective shall be eligible to participate in the Plan, subject
to limitations imposed by Section 423(b) of the Code.


(b)   Any provisions of the Plan
to the contrary notwithstanding, no Employee shall be granted an option under
the Plan (i) if, immediately after the grant, such Employee (or any other
person whose stock would be attributed to 













such Employee pursuant to Section 425(d) of the Code)
would own stock and/or hold outstanding options to purchase stock possessing
five percent (5%) or more of the total combined voting power or value of all
classes of stock of the Company or of any subsidiary of the Company, or (ii)
which permits his rights to purchase stock under all employee stock purchase
plans of the Company and its subsidiaries to accrue at a rate which exceeds
Twenty Five Thousand Dollars ($25,000) of fair market value of such stock
(determined at the time such option is granted) for each calendar year in which
such option is outstanding at any time.


4.     Offering Periods.  The Plan shall be implemented by one offering
during each six month period of the Plan, commencing on or about, and
continuing thereafter until terminated in accordance with paragraph 19
hereof.  The Board of Directors of the
Company shall have the power to change the duration of offering periods with
respect to future offerings without stockholder approval if such change is
announced at least fifteen (15) days prior to the scheduled beginning at the
first offering period to be affected.


5.     Participation.


(a)   An eligible Employee may
become a participant in the Plan by completing a subscription agreement
authorizing payroll deduction on the form provided by the Company and filing it
with the Company’s payroll office prior to the applicable Offering Date, unless
a later time for filing the subscription agreement is set by the Board for all
eligible employees with respect to a given offering.


(b)   Payroll deductions for a
participant shall commence on the first payroll following the Offering Date and
shall end on the Exercise Date of the offering to which such authorization is
applicable, unless sooner terminated by the participant as provided in
paragraph 10.


6.     Payroll Deductions.


(a)   At the time a participant
files his subscription agreement, he shall elect to have payroll deductions
made on each payday during the offering period in an amount not exceeding ten
percent (10%) of the Compensation which he received on the payday immediately
preceding the Offering Date, and the aggregate of such payroll deductions
during the offering period shall not exceed ten percent (10%) of his aggregate
Compensation during said offering period.


(b)   All payroll deductions made
by a participant shall be credited to his account under the Plan.  A participant may not make any additional
payments into such account.


(c)   A participant may discontinue
his participation in the Plan as provided in paragraph 10, or may lower, but
not increase, the rate of his payroll deductions during the offering period by
completing or filing with the Company a new authorization for payroll
deduction.  The change in rate shall be
effective fifteen (15) days following the Company’s receipt of the new
authorization.


7.     Grant of Option.


(a)   On the Offering Date of each
six month offering period, each eligible Employee participating in the Plan
shall be granted an option to purchase (at the per share option price) up to a
number of shares of the Company’s Common Stock determined by dividing such
Employee’s payroll deductions to be accumulated during such offering period
(not to exceed an amount equal to ten percent (10%) of his Compensation as of
the date of the commencement of the applicable offering period) by eighty-five
percent (85%) of the fair market value of a share of the Company’s Common Stock
on the Offering Date, subject to the limitations set forth in Section 3(b) and
12 hereof.  Fair market value of a share
of the Company’s Common Stock shall be determined as provided in Section 7(b)
herein.  Notwithstanding the foregoing,
no employee shall be granted an option to purchase more than 5,000 shares of
the Company’s Common Stock during any six-month offering period.


(b)   The option price per share
of the shares offered in a given offering period shall be the lower of:  (i) 85% of the fair market value of a share
of the Common Stock of the Company on the Offering Date; or (ii) 85% of the
fair market value of a share of the Common Stock of the Company on the Exercise
Date.  The fair market value of the 



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Company’s Common Stock on a given date shall be the
mean of the reported bid and asked prices for that date except that the fair
market value on the Offering Date of the initial offering period shall be the
initial public offering price.


8.     Exercise of Option.  Unless a participant withdraws from the Plan
as provided in paragraph 10, his option for the purchase of shares will be
exercised automatically on the Exercise Date of the offering period, and the
maximum number of full shares subject to option will be purchased for him at
the applicable option price with the accumulated payroll deductions in his
account.  If the total amount of payroll
deductions for a participant during the offering period exceeds the purchase
price of such shares as determined in Section 7(a), such excess amount will be
refunded to the participant.


9.     Delivery.  As promptly as practicable after the Exercise
Date of each offering, the Company shall arrange the delivery to each
participant, as appropriate, of a certificate representing the shares purchased
upon exercise of his option.  Any cash
remaining to the credit of a participant’s account under the Plan after a
purchase by him of shares at the termination of each offering period, or which
is insufficient to purchase a full share of Common Stock of the Company, shall
be returned to said participant.


10.  Withdrawal; Termination of Employment.


(a)   A participant may withdraw
all but not less than all the payroll deductions credited to his account under
the Plan at any time prior to the Exercise Date of the offering period by
giving written notice to the Company. 
All of the participant’s payroll deductions credited to his account will
be paid to him promptly after receipt of his notice of withdrawal and his
option for the current period will be automatically terminated, and no further
payroll deductions for the purchase of shares will be made during the offering
period.


(b)   Upon termination of the
participant’s employment prior to the Exercise Date of the offering period for
any reason, including retirement or death, the payroll deductions credited to
his account will be returned to him or, in the case of his death, to the person
or persons entitled thereto under paragraph 14, and his option will be
automatically terminated.


(c)   In the event an Employee
fails to remain in the continuous employ of the Company for at least twenty
(20) hours per week during the offering period in which the employee is a
participant, he will be deemed to have elected to withdraw from the Plan and
the payroll deductions credited to his account will be returned to him and his
option terminated.


(d)   A participant’s withdrawal
from an offering will not have any effect upon his eligibility to participate
in a succeeding offering or in any similar plan which may hereafter be adopted
by the Company.


11.  Interest.  No interest shall accrue on the payroll
deductions of a participant in the Plan.


12.  Stock.


(a)   The maximum number of shares
of the Company’s Common Stock that shall be made available for sale under the
Plan shall be 1,000,000 shares, subject to adjustment upon changes in
capitalization of the Company as provided in paragraph 18.  If the total number of shares which would
otherwise be subject to options granted pursuant to Section 7(a) hereof on the
Offering Date of an offering period exceeds the number of shares then available
under the Plan (after deduction of all shares for which options have been
exercised or are then outstanding), the Company shall make a pro rata
allocation of the shares remaining available for option grant in as uniform a
manner as shall be practicable and as it shall determine to be equitable.  In such event, the Company shall give written
notice of such reduction of the number of shares subject to the option to each
Employee affected thereby and shall similarly reduce the rate of payroll
deductions, if necessary.


(b)   The participant will have no
interest or voting right in shares covered by his option until such option has
been exercised.



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(c)   Shares to be delivered to a
participant under the Plan will be registered in the name of the participant or
in the name of the participant and his spouse.


13.  Administration.  The Plan shall be administered by the Board
of Directors of the Company or a committee appointed by the Board.  The administration, interpretation or
application of the Plan by the Board or its committee shall be final,
conclusive and binding upon all participants. 
Members of the Board who are eligible Employees are permitted to
participate in the Plan, provided that:


(a)   Members of the Board who are
eligible to participate in the Plan may not vote on any matter affecting the
administration of the Plan or the grant of any option pursuant to the Plan.


(b)   If a Committee is
established to administer the Plan, no member of the Board who is eligible to
participate in the Plan may be a member of the Committee.


14.  Designation of Beneficiary.


(a)   A participant may file a
written designation of a beneficiary who is to receive any shares and cash, if
any, from the participant’s account under the Plan in the event of such
participant’s death subsequent to the end of the offering period but prior to
delivery to him of such shares and cash. 
In addition, a participant may file a written designation of a
beneficiary who is to receive any cash from the participant’s account under the
Plan in the event of such participant’s death prior to the Exercise Date of the
offering period.


(b)   Such designation of
beneficiary may be changed by the participant at any time by written
notice.  In the event of the death of a
participant and in the absence of a beneficiary validly designated under the
Plan who is living at the time of such participant’s death, the Company shall
deliver such shares and/or cash to the executor or administrator of the estate
of the participant, or if no such executor or administrator has been appointed
(to the knowledge of the Company), the Company, in its discretion, may deliver
such shares and/or cash to the spouse or to any one or more dependents or
relatives of the participant, or if no spouse, dependent or relative is known
to the Company, then to such other person as the Company may designate.


15.  Transferability.  Neither payroll deductions credited to a
participant’s account nor any rights with regard to the exercise of an option
or to receive shares under the Plan may be assigned, transferred, pledged or
otherwise disposed of in any way (other than by will, the laws of descent and
distribution or as provided in paragraph 14 hereof) by the participant.  Any such attempt at assignment, transfer,
pledge or other disposition shall be without effect, except that the Company
may treat such act as an election to withdraw funds in accordance with
paragraph 10.


16.  Use of Funds.  All payroll deductions received or held by
the Company under the Plan may be used by the Company for any corporate
purpose, and the Company shall not be obligated to segregate such payroll
deductions.


17.  Reports.  Individual accounts will be maintained for
each participant in the Plan.  Statements
of account will be given to participating Employees semi-annually promptly
following the Exercise Date, which statements will set forth the amounts of
payroll deductions, the per share purchase price, the number of shares
purchased and the remaining cash balance, if any.


18.  Adjustments Upon Changes in Capitalization.  Subject to any required action by the
stockholders of the Company, the number of shares of Common Stock covered by
each option under the Plan which has not yet been exercised and the number of
shares of Common Stock which have been authorized for issuance under the Plan
but have not yet been placed under option (collectively, the “Reserves”), as
well as the price per share of Common Stock covered by each option under the
Plan which has not yet been exercised, shall be appropriately and equitably
adjusted for any increase or decrease in the number of issued shares of Common
Stock resulting from a merger, consolidation, sale or exchange of assets of the
Company, reorganization, recapitalization, reclassification, combination of
shares, stock split, reverse stock split, spin-off, payment of a stock dividend
(but only on the Common Stock) or any other equity restructuring transaction,
as that term is defined in Statement of Financial Accounting Standards No. 123
(revised).  Such adjustment shall be made
by the Board, whose determination in that 



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respect shall be final, binding and conclusive.  Except as expressly provided herein, no issue
by the Company of shares of stock of any class, or securities convertible into
shares of stock of any class, shall affect, and no adjustment by reason thereof
shall be made with respect to, the number or price of shares of Common Stock
subject to an option.


19.  Amendment or Termination.  The Board of Directors of the Company may at
any time terminate or amend the Plan.  No
such termination can affect options previously granted, nor may an amendment
make any change in any option theretofore granted which adversely affects the
rights of any participant, nor may an amendment be made without prior approval
of the stockholders of the Company if such amendment would:


(a)   increase the number of
shares that may be issued under the Plan;


(b)   Permit payroll deductions at
a rate in excess of ten percent (10%) of the participant’s Compensation;


(c)   Modify the requirements
concerning which employees (or class of employees) are eligible for participation
in the Plan; or


(d)   Materially increase the
benefits which may accrue to participants under the Plan.


20.  Notices.  All notices or other communications by a
participant to the Company under or in connection with the Plan shall be deemed
to have been duly given when received in the form specified by the Company at
the location, or by the person, designated by the Company for the receipt
thereof.


21.  Stockholder Approval.  Continuance of the Plan shall be subject to
approval by the stockholders of the Company within twelve months before or
after the date the Plan is adopted.  If
such shareholder approval is obtained at a duly held stockholders’ meeting, it
may be obtained by the affirmative vote of the holders of a majority of the
outstanding shares of the Company present or represented and entitled to vote
thereon, which approval shall be:


(a)(1) solicited
substantially in accordance with Section 14(a) of the Securities Act of 1934,
as amended (the “Act”) and the rules and regulations promulgated thereunder, or
(2) solicited after the Company has furnished in writing to the holders
entitled to vote substantially the same information concerning the Plan as that
which would be required by the rules and regulations in effect under Section
14(a) of the Act at the time such information is furnished; and


(b) obtained at or prior
to the first annual meeting of stockholders held subsequent to the first
registration of Common Stock under Section 12 of the Act.


In the case of approval by written consent, it must be obtained by the
unanimous written consent of all stockholders of the Company.


22.  Conditions Upon Issuance of Shares.  Shares shall not be issued with respect to an
option unless the exercise of such option and the issuance and delivery of such
shares pursuant thereto shall comply with all applicable provisions of law,
domestic or foreign, including, without limitation, the Securities Act of 1933,
as amended, the Securities Exchange Act of 1934, as amended, the rules and
regulations promulgated thereunder, and the requirements of any stock exchange
upon which the shares may then be listed, and shall e further subject to the
approval of counsel for the Company with respect to such compliance.


As a condition to the exercise of an option, the Company may require the
person exercising such option to represent and war rant at the time of any such
exercise that the shares are being purchased only for investment and without
any present intention to sell or distribute such shares if, in the opinion of
counsel for the Company, such a representation is required by any of the
aforementioned applicable provisions of law.



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