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

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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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