<PAGE>
                                                                   EXHIBIT 10.50

                                     Approved and adopted by Board of Directors,
                                                              September 16, 2002



                             GEN-PROBE INCORPORATED
                  CHANGE-IN-CONTROL SEVERANCE COMPENSATION PLAN


                                    Preamble

         The Board of Directors of Gen-Probe Incorporated believes that it is in
the best interest of Gen-Probe (the "Company") to provide additional security to
the Employees of the Company and its subsidiaries (the "Employees") and thereby
induce such individuals to continue in their employment and enhance their
ability to perform effectively and without undue distraction should the Company
be rumored to be or become the target of an attempted acquisition or merger.

         Accordingly, in order to (a) induce the Employees to remain in the
employ of the Company and in consideration for their continuing employment and
(b) facilitate the hiring of new Employees the Company adopts the plan
hereinafter set forth (the "Plan") for the payment of certain Benefits in the
event that any Employee's employment is terminated after a Change in Control, by
the Company without Cause.

         The Plan is an employee welfare benefit plan subject to the Employee
Retirement Income Security Act of 1974, as amended ("ERISA"). This Plan document
is also the summary plan description of the Plan.

         PLEASE NOTE THAT WORDS THAT ARE CAPITALIZED IN THIS PLAN HAVE SPECIAL
DEFINITIONS THAT ARE CONTAINED IN SECTION 8.

                                 Plan Provisions

         1. Termination Following Change in Control.

         1.1 Participation in Plan. An Employee who is not an officer of the
Company shall be entitled to participate in this Plan (a) upon the termination
of his or her employment within 12 months following a Change in Control by the
Company without Cause, provided in any case that the termination occurs within
the period set forth in Section 4.1. In no event shall an Employee's termination
of employment be deemed to be without Cause for purposes of this Plan if such
Employee immediately accepts Employment with the Company's successor or
acquirer, unless he or she is subsequently terminated without Cause by the
successor or acquirer within the 12 months following the Change in Control.

         1.2 Compensation. The compensation payable under the circumstances set
forth in Section 1.1 shall be equal to the amount of the Employee's weekly
salary on the date of the





<PAGE>

Change in Control (the "Weekly Salary") to be paid for the number of weeks
determined pursuant to Section 1.3.

         1.3 Duration of Benefits. The Weekly Salary shall be paid to the
Employee for a period of weeks as set forth below, based on the Employee's
position with the Company on the date of the Change in Control:

<Table>
<Caption>
              POSITION                                  DURATION OF BENEFIT
 -----------------------------------------------------------------------------------------------
                                                Base                    Tenure Adjustment
                                    ------------------------------------------------------------
<S>                                <C>                           <C>
 Exempt employees in Grades E-12              12 weeks            Plus an additional 2 weeks
 and above (other than officers)                                  for each full year of
                                                                  service, to an aggregate
                                                                  maximum of 30 weeks

 Exempt employees in Grades E-9 to             8 weeks            Plus an additional 2 weeks
 E-11                                                             for each full year of
                                                                  service, to an aggregate
                                                                  maximum of 30 weeks

 Exempt employees in Grades E-1 to             4 weeks            Plus an additional 1.5 weeks
 E-8                                                              for each full year of
                                                                  service, to an aggregate
                                                                  maximum of 26 weeks

 Non-exempt employees                          3 weeks            Plus an additional 1 week
                                                                  for each full year of
                                                                  service, to an aggregate
                                                                  maximum of 26 weeks

 -----------------------------------------------------------------------------------------------
</Table>

         2. Payments Upon Termination. Upon a termination under the
circumstances stated in Section 1.1, the Employee shall be paid as follows:

         2.1 The Company shall pay the Employee the full amount due under his or
her Compensation Plan through the Date of Termination, at the rate in effect at
the time Notice of Termination is given, together with the amount, if any, of
any bonus for a past fiscal year that has not yet been paid to him under any
bonus plan. If the Date of Termination occurs after the end of a fiscal year for
which no bonus has yet been awarded, the Employee will be paid a bonus
calculated on the same basis as the bonus awarded to him/her for the prior
fiscal year, or, if he or she was not eligible to participate in the applicable
bonus plan in the prior fiscal year, his or her




                                       2

<PAGE>

bonus will be calculated at the average rate paid in the prior fiscal year to
Employees of comparable grade level.

         2.2 In lieu of any further salary payment to the Employee for periods
subsequent to the Date of Termination, provided the Employee has executed (and
not revoked within any applicable period) a release of claims against the
Company in a form acceptable to the Company, the Company shall pay, in
accordance with the provisions of Section 2.3 below, as severance pay to him
after the Date of Termination, Weekly Salary calculated as set forth in Sections
1.2 and 1.3.

         2.3 The Employee may elect to receive either (a) the full amount of the
Weekly Salary paid in equal installments every week during the period set forth
in Section 1.3, such payments to commence on the second Friday following the
Date of Termination; or (b) an amount equal to ninety percent (90%) of the
aggregate Weekly Salary to be paid under Section 1.3, paid in one lump sum
within fifteen (15) days following the Date of Termination.

         2.4 The Company shall also pay to the Employee all reasonable legal
fees and expenses incurred by the Employee in successfully seeking to obtain or
enforce any right provided by this Plan.

         2.5 Until the earlier of (a) the period set forth in Section 1.3
following the Date of Termination or (b) the Employee's commencement of full
time employment with a new employer, the Company shall pay on the Employee's
behalf the costs of premiums under the Company's medical and dental plans,
programs or arrangements in which he or she was entitled to participate
immediately prior to the Date of Termination. The Company's payment of any
premiums under this Section 2.5 shall not in any manner extend the applicable
coverage period for the Employee under the Consolidated Omnibus Reconciliation
Act of 1985, as amended ("COBRA").

         2.6 The Employee shall not be required to mitigate the amount of any
payment provided for in Sections 2.2 and 2.5 by seeking other employment or
otherwise, nor shall the amount of any such payment be reduced by any
compensation earned by the Employee as the result of employment by another
employer after the Date of Termination, or otherwise.

         2.7 All amounts payable under this Plan shall be subject to (and
reduced by) any applicable required tax withholdings.

         3. Company's Rights Prior to Change in Control. No provision contained
herein shall affect the Company's right or ability, prior to a Change in
Control, to (1) terminate an Employee's employment at any time, with or without
cause or (2) reduce Employee's compensation (including reduction or elimination
of any bonus compensation). Nothing in this Plan shall in any way require the
Company to provide any benefits prior to a Change in Control, nor shall this
Plan ever be construed in any way as establishing any policies or requirements
for severance benefits for any Employee whose employment with the Company
terminates prior to a Change in Control, nor shall anything in this Plan in any
way affect the Company's right in its absolute discretion to change one or more
benefit plans, including but not limited to pension





                                       3
<PAGE>

plans, dental plans, health care plans, savings plans, bonus plans, vacation pay
plans, disability plans, and the like.

         4. Duration and Amendment.

         4.1 This Plan shall become effective on September 16, 2002 and shall
terminate seven (7) years after such date unless, prior thereto, a Change in
Control shall have occurred, in which case all rights granted hereunder shall be
vested, and the Plan shall continue in effect and shall apply to any termination
of employment that occurs within twelve (12) months after the effective date of
the Change in Control.

         4.2 The Company expressly reserves the right to amend or terminate this
Plan during its term at any time before a Change in Control. The Company
expressly waives the right to amend or terminate this Plan during its term at
any time following a Change in Control in any manner that reduces the benefits
or rights provided hereunder, and the Company acknowledges that the rights of
each Employee hereunder shall be binding and irrevocable upon any Change in
Control. Any purported amendment or termination of such Plan that reduces the
benefits or rights provided hereunder following a Change in Control shall be
ineffective. No Employee shall lose any right hereunder for failing to contest
such a purported amendment or termination.

         5. Successors: Binding Agreement.

         5.1 The Company will require any successor (whether direct or indirect,
by purchase, merger, consolidation or otherwise) to all or substantially all of
the business and/or assets of the Company, to expressly assume and agree to
honor this Plan, if such assumption is legally required to make this Plan
enforceable against the successor.

         5.2 This Plan shall be binding on any successor to the business and/or
assets of the Company that executes and delivers the agreement provided for in
Section 5.1 or that otherwise becomes bound by all the terms and provisions of
this Plan by operation of law. The Company shall promptly notify each Employee
of any succession by purchase, merger, consolidation or otherwise to all or
substantially all the business and/or assets of the Company and shall state
whether or not the successor has executed the agreement required by Section 5.1
and, if so, shall make a copy of such agreement available to each Employee.

         5.3 If the Employee should die after termination and while any amount
would still be payable to him hereunder if he had continued to live, all such
amounts, unless otherwise provided herein, shall be paid in accordance with the
terms of this Plan to his or her devisee, legatee or other designee or, if there
be no such designee, to his or her estate. For this purpose, this Plan shall be
enforceable by the Employee's personal or legal representatives, executors,
administrators, successors, heirs, distributees, devisees and legatees.

         5.4 The Company expressly acknowledges and agrees that each Employee
shall have a contractual right to the rights and benefits provided hereunder,
and the Company expressly waives any right it may have to deny liability for any
breach of its contractual commitment hereunder upon the grounds of lack of
consideration, accord and satisfaction or any similar





                                       4
<PAGE>

defense. In any dispute arising after a Change in Control as to whether an
Employee is entitled to benefits or rights under this Plan, there shall be a
presumption that the Employee is so entitled and the burden of proving otherwise
shall be on the Company or any successor.

         5.5 All benefits to be provided hereunder shall be in addition to any
pension, disability, worker's compensation, other Company benefit plan
distribution, unpaid vacation or other unpaid compensation that the Employee has
at his or her Date of Termination, except that the benefits shall be reduced by
payments under any other severance policy of the Company or under any contract
or arrangement between the Employee and the Company requiring the payment of
benefits upon a termination of employment. Any such policy, contract or
arrangement shall take precedence over this Plan if it provides rights and or
benefits that are, considered in the aggregate, more favorable to the Employee,
than the rights and benefits provided hereunder. Any payment that the Company is
required to make to the Employee under any statue or regulation requiring
payment and/or notice on termination will be deducted from the amount of
benefits payable under this Plan.

         6. Claims Provisions and Governing Law.

         6.1 Claims Procedures.

             (a) It is not necessary to submit a formal claim to receive
benefits payable under this Plan. However, if any person (a "Claimant") believes
that benefits are being denied improperly, that the Plan is not being operated
properly, that fiduciaries of the Plan have breached their duties, or that the
Claimant's legal rights are being violated with respect to the Plan, the
Claimant must file a formal claim, in writing, with the Company. This
requirement applies to all claims that any Claimant has with respect to the
Plan, including claims against fiduciaries and former fiduciaries, except to the
extent the Company determines, in its sole discretion, that it does not have the
power to grant all relief reasonably being sought by the Claimant.

             (b) A formal claim must be filed within 90 days after the date the
Claimant first knew or should have known of the facts on which the claim is
based, unless the Company in writing consents otherwise. The Company shall
provide a Claimant, on request, with a copy of the claims procedures established
under subsection (c).

             (c) The Company has adopted procedures for considering claims
(which are set forth in Appendix A), which it may amend from time to time, as it
sees fit. These procedures shall comply with all applicable legal requirements.
These procedures may provide that final and binding arbitration shall be the
ultimate means of contesting a denied claim (even if the Company or its
delegates have failed to follow the prescribed procedures with respect to the
claim). The right to receive benefits under this Plan is contingent on a
Claimant using the prescribed claims and arbitration procedures to resolve any
claim.

         6.2 Governing Law. This Plan is a welfare plan subject to ERISA and it
shall be interpreted, administered, and enforced in accordance with that law. To
the extent that state law is applicable, the validity, interpretation,
construction and performance of this Plan shall be



                                       5

<PAGE>

governed by the laws of the State of California, notwithstanding the choice of
law principles of that or any other state or country.

         7. Notices. For the purposes of this Plan, notices and all other
communications provided for in the Plan shall be in writing and shall be deemed
to have been duly given when delivered or mailed by certified or registered
mail, return receipt requested, postage prepaid, addressed: (a) if to an
Employee, to his or her latest address as reflected on the Company's employment
records, with a copy to him at his or her place of employment, if known; and (b)
if to the Company, to 10210 Genetic Center Drive, San Diego, California 92121,
Attention: General Counsel, or to such other address as the Company may furnish
to each Employee in writing with specific reference to the Plan and the
importance of the notice, except that notice of change of address shall be
effective only upon receipt.

         8. Administration.

            (a) The Company is responsible for the general administration and
management of the Plan and shall have all powers and duties necessary to fulfill
its responsibilities, including, but not limited to, the discretion to interpret
and apply the Plan and to determine all questions relating to eligibility for
benefits. The Plan shall be interpreted in accordance with its terms and their
intended meanings. However, the Company and all Plan fiduciaries shall have the
discretion to interpret or construe ambiguous, unclear, or implied (but omitted)
terms in any fashion they deem to be appropriate in their sole discretion, and
to make any findings of fact needed in the administration of the Plan. The
validity of any such interpretation, construction, decision, or finding of fact
shall not be given de novo review if challenged in court, by arbitration, or in
any other forum, and shall be upheld unless clearly arbitrary or capricious.

            (b) All actions taken and all determinations made in good faith by
the Company or by Plan fiduciaries will be final and binding on all persons
claiming any interest in or under the Plan. To the extent the Company or any
Plan fiduciary has been granted discretionary authority under the Plan, the
Company's or Plan fiduciary's prior exercise of such authority shall not
obligate it to exercise its authority in a like fashion thereafter.

            (c) If, due to errors in drafting, any Plan provision does not
accurately reflect its intended meaning, as demonstrated by consistent
interpretations or other evidence of intent, or as determined by the Company in
its sole discretion, the provision shall be considered ambiguous and shall be
interpreted by the Company and all Plan fiduciaries in a fashion consistent with
its intent, as determined in the sole discretion of the Company. The Company
shall amend the Plan retroactively to cure any such ambiguity.

            (d) No Plan fiduciary shall have the authority to answer questions
about any pending or final business decision of the Company or any affiliate
that has not been officially announced, to make disclosures about such matters,
or even to discuss them, and no person shall rely on any unauthorized,
unofficial disclosure. Thus, before a decision is officially announced, no
fiduciary is authorized to tell any person, for example, that his or her
employment will not be terminated or that the Company will or will not offer
exit incentives in the future. Nothing in this subsection shall preclude any
fiduciary from fully participating in the consideration, making, or




                                       6
<PAGE>

official announcement of any business decision.

             (e) This Section may not be invoked by any person to require the
Plan to be interpreted in a manner inconsistent with its interpretation by the
Plan Administrator or other Plan fiduciaries.

            9. Definitions. The capitalized terms used in this Plan have the
following meanings for purposes of the Plan:

         9.1 "Cause" means:

             (a) the willful and continued failure by an Employee to
substantially perform his or her duties with the Company (other than any such
failure resulting from his or her incapacity due to physical or mental illness)
for a period of thirty (30) or more consecutive calendar days after a written
demand for substantial performance is delivered to him by the Company, which
demand specifically identifies the manner in which the Company believes that the
Employee has not substantially performed his or her duties;

             (b) the commission by an Employee of any act of fraud, theft or
criminal dishonesty with respect to the Company or any of its divisions or
affiliates, or the conviction of the Employee of any felony;

             (c) a determination by the Company that an Employee is habitually
addicted to a Controlled Substance (as defined herein) which has not been
obtained directly, or pursuant to a valid prescription or order, from a medical
practitioner while acting in the course of his or her professional practice; or

             (d) the commission of any act involving moral turpitude which (i)
brings the Company or any of its affiliates into public disrepute or disgrace,
or (ii) causes material injury to the customer relations, operations or the
business prospects of the Company.

As used herein, "Controlled Substance" shall have the meaning set forth in 21
U.S.C.A. Sections 812 and 844 (1944 Supplement).

         9.2 "Change in Control" shall mean a change in ownership or control of
the Company effected through any of the following transactions:

             (a) any person or related group of persons (other than the Company
or a person that, prior to such transaction, directly or indirectly controls, is
controlled by, or is under common control with, the Company) directly or
indirectly acquires beneficial ownership (within the meaning of Rule 13d-3 under
the Exchange Act) of securities possessing more than fifty percent (50%) of the
total combined voting power of the Company's outstanding securities pursuant to
a tender or exchange offer for securities of the Company; or

             (b) there is a change in the composition of the Board of Directors
of the Company over a period of thirty-six (36) consecutive months (or less)
such that a majority of the Board members (rounded up to the nearest whole
number) ceases, by reason of one or more




                                       7
<PAGE>

proxy contests for the election of Board members, to be comprised of individuals
who either (i) have been Board members continuously since the beginning of such
period or (ii) have been elected or nominated for election as Board members
during such period by at least a majority of the Board members described in
clause (i) who were still in office at the time such election or nomination was
approved by the Board; or

             (c) consummation of a merger or consolidation of the Company with
any other corporation (or other entity), other than a merger or consolidation
which would result in the voting securities of the Company outstanding
immediately prior thereto continuing to represent (either by remaining
outstanding or by being converted into voting securities of the surviving entity
or another entity) more than 66-2/3% of the combined voting power of the voting
securities of the Company or such surviving entity outstanding immediately after
such merger or consolidation; provided, however, that a merger or consolidation
effected to implement a recapitalization of the Company (or similar transaction)
in which no person acquires more than 25% of the combined voting power of the
Company's then outstanding voting securities shall not constitute a Change in
Control.

         9.3 "Compensation Plan" means the Employee's base salary, targeted
commissions and other cash compensation including bonuses for the applicable
year.

         9.4 "Date of Termination" means if the Employee's employment is
terminated by the Company for any reason, the date on which the Employee
receives a notice of termination; provided that if within thirty (30) days after
any notice of termination is given the Employee notifies the Company that a
dispute exists concerning the termination, the Date of Termination shall be the
date on which the dispute is finally determined, either by mutual written
agreement of the parties, or by an order of the arbitrators to whom the dispute
is submitted under Section 6 of this Plan.

         9.5 "Employee" means an Employee of the Company. All Employees shall be
referred to collectively as "Employees."

         9.6 "Subsidiary" means a corporation at least fifty percent (50%) of
whose stock is owned, directly or indirectly, by Gen-Probe Incorporated
immediately prior to a Change in Control. All such corporations shall be
collectively referred to as "Subsidiaries."

         9.7 "Weekly Salary" has the meaning stated in Section 1.2.

         10. Miscellaneous.

         10.1 After a Change in Control, no successor to the Company shall
request any Employee to release, modify, waive or discharge his or her rights
under this Plan. No failure to enforce or waiver by any Employee at any time of
any breach by the Company of, or non-compliance with, any condition or provision
of the Plan to be performed by the Company shall be deemed a waiver of similar
or dissimilar provisions or conditions at the same or at any prior or subsequent
time.




                                       8
<PAGE>

         10.2 The invalidity or unenforceability of any provision of this Plan
shall not affect the validity or enforceability of any other provision of this
Plan, which shall remain in full force and effect. Any such invalid or
unenforceable provision shall be replaced by one that is valid and enforceable
and that, as closely as possible, achieves the same result as the invalid or
unenforceable provision.

         10.3 This Plan constitutes is the complete, final, and exclusive
embodiment of the Company's agreement with regard to the payment of severance
benefits and supersedes all prior letter agreements and understandings between
the Company and any Employee.

         WHEREFORE, Gen-Probe Incorporated has caused this plan to be executed
by its undersigned duly authorized Employee this 16th day of September 2002.

                                      GEN-PROBE INCORPORATED



                                      By:
                                          --------------------------------------
                                          Henry L. Nordhoff
                                          President and Chief Executive Employee




                                        9

<PAGE>


                                   APPENDIX A

                   DETAILED CLAIMS AND ARBITRATION PROCEDURES


         1.       Claims Procedure

                  Initial Claims

                  All claims shall be presented to the Company in writing.
Within 90 days after receiving a claim, a claims official appointed by the
Company shall consider the claim and issue his or her determination thereon in
writing. The claims official may extend the determination period for up to an
additional 90 days by giving the Claimant written notice. The initial claim
determination period can be extended further with the consent of the Claimant.
Any claims that the Claimant does not pursue in good faith through the initial
claims stage shall be treated as having been irrevocably waived.

                  Claims Decisions

                  If the claim is granted, the benefits or relief the Claimant
seeks shall be provided. If the claim is wholly or partially denied, the claims
official shall, within 90 days (or a longer period, as described above), provide
the Claimant with written notice of the denial, setting forth, in a manner
calculated to be understood by the Claimant: (1) the specific reason or reasons
for the denial; (2) specific references to the provisions on which the denial is
based; (3) a description of any additional material or information necessary for
the Claimant to perfect the claim, together with an explanation of why the
material or information is necessary; and (4) an explanation of the procedures
for appealing denied claims. If the Claimant can establish that the claims
official has failed to respond to the claim in a timely manner, the Claimant may
treat the claim as having been denied by the claims official.

                  Appeals of Denied Claims

                  Each Claimant shall have the opportunity to appeal the claims
official's denial of a claim in writing to an appeals official appointed by the
Company (which may be a person, committee, or other entity). A Claimant must
appeal a denied claim within 60 days after receipt of written notice of denial
of the claim, or within 60 days after it was due if the Claimant did not receive
it by its due date. The Claimant (or his or her duly authorized representative)
may review pertinent documents in connection with the appeals proceeding and may
present issues and comments in writing. The Claimant may present only the
evidence and theories during the appeal that the Claimant presented during the
initial claims stage, except for information the claims official may have
requested the Claimant to provide to perfect the claim. Any claims that the
Claimant does not pursue in good faith through the appeals stage, such as by
failing to file a timely appeal request, shall be treated as having been
irrevocably waived.

                  Appeals Decisions

                  The decision by the appeals official shall be made not later
than 60 days after the written appeal is received by the Company, unless special
circumstances require an extension of



                                      A-1
<PAGE>

time, in which case a decision shall be rendered as soon as possible, but not
later than 120 days after the appeal was filed, unless the Claimant agrees to a
further extension of time. The appeal decision shall be in writing, shall be set
forth in a manner calculated to be understood by the Claimant, and shall include
specific reasons for the decision, as well as specific references to the
provisions on which the decision is based, if applicable. If a Claimant does not
receive the appeal decision by the date it is due, the Claimant may deem his or
her appeal to have been denied.

                  Procedures

                  The Company shall adopt procedures by which initial claims
shall be considered and appeals shall be resolved; different procedures may be
established for different claims. All procedures shall be designed to afford a
Claimant full and fair consideration of his or her claim.

                  Arbitration of Rejected Appeals

                  If a Claimant has pursued his or her claim through the appeal
stage of these claims procedures, the Claimant may contest the denial of that
claim through arbitration, as described below. In no event shall any denied
claim be subject to resolution by any means (such as in a court of law) other
than arbitration in accordance with the following provisions.

         2.       Arbitration Procedure

                  The Company by establishing the Plan agrees to this provision
for arbitration, and a Claimant shall by that action agree to this provision for
arbitration. Any denied claim under this Plan shall be settled by arbitration
and by one arbitrator in accordance with the applicable rules of the Judicial
Mediation & Arbitration Service ("JAMS") and judgment upon the award rendered by
the arbitrator may be entered in any court having jurisdiction thereof, subject,
however, to the terms of Appendix A. The Company and a Claimant contemplate and
agree that (i) as a consequence of asserting such claim, the Employee will
necessarily incur, as part of his or her damages, his or her attorneys' fees and
costs of arbitration, including but not limited to the administrative fees,
expenses, and arbitrator's fees; (ii) if the Employee is awarded damages, the
arbitrator shall include in that award the consequential damages described
above; and (iii) in no event may the Company recover any of its attorneys' fees
or costs of arbitration, including but not limited to the administration fees,
expenses, and arbitrator's fees, unless the Arbitrator affirmatively and
expressly finds that the Employee commenced the arbitration without probable
cause.

                  For the purposes of any such arbitration, there shall be a
conclusive presumption that there has been a "Change in Control" within the
meaning of Section 9.4 of this Plan, unless (i) the Company agrees to submit the
issue of whether there has been a "Change in Control" to the arbitrator, or (ii)
prior to any award in the arbitration proceeding the Company shall have filed an
action or cross-complaint for, or obtained, a declaratory judgment of a U.S.
federal court in which court proceeding any Employee covered by this Plan is
named as a party, finally determining that there has not been such "Change in
Control." The arbitration hereunder shall be suspended pending such judicial
determination. A Claimant who gives notice to the Company of


                                      A-2

<PAGE>

his or her intention to arbitrate shall by that action be deemed to consent to
be bound by the declaratory judgment issued by such court on the issue of
"Change in Control."

                  Any arbitration hereunder shall be in San Diego, California.
The invalidity or unenforceability of any part of these arbitration procedures
shall not affect the validity of the rest of the procedures.



                                      A-3

<PAGE>


                                   APPENDIX B

                             ADDITIONAL INFORMATION

                               RIGHTS UNDER ERISA

                  Each participant in the Plan is entitled to certain rights and
protections under ERISA. ERISA provides that all Plan participants will be
entitled to:

Receive Information About Your Plan and Benefits

1. Examine, without charge, at the Plan administrator's office and at certain
Company offices, all Plan documents including collective bargaining agreements
and copies of all documents filed by the Plan with the U.S. Department of Labor,
and available at the Public Disclosure Room of the Pension and Welfare Benefit
Administration, such as annual reports and Plan descriptions.

2. Obtain, upon written request to the Plan administrator, copies of documents
governing the operation of the Plan, including collective bargaining agreements
and copies of the latest annual report (Form 5500 Series) and updated summary
plan description. The Plan administrator may make a reasonable charge for the
copies.

3. Receive a summary of the Plan's annual financial report. The Plan
administrator is required by law to furnish each participant with a copy of this
summary annual report.

4. Continue health care coverage for the participant, his/her spouse or
dependent if there is a loss of coverage as a result of a qualifying event. The
participant and/or his dependents may have to pay for such coverage. Review the
Company's group health insurance plan and summary plan description on the rules
governing your COBRA continuation coverage rights.

Prudent Actions by Plan Fiduciaries

                  In addition to creating rights for Plan participants, ERISA
imposes duties upon the people who are responsible for the operation of the
employee benefit plan. The people who operate the Plan, called "fiduciaries" of
the Plan, have a duty to do so prudently and in the interest of Plan
participants and beneficiaries. No one, including the Company or any other
person, may fire or otherwise discriminate against a Plan participant in any way
to prevent them from obtaining a welfare benefit or exercising any right under
ERISA.

Enforce Your Rights

                  If a claim for a welfare benefit is denied or ignored, in
whole or in part, the affected Plan participant has a right to know why this was
done, to obtain copies of documents relating to the decision without charge, and
to appeal any denial, all within certain time schedules.


                                      B-1
<PAGE>

                  Under ERISA, there are steps a participant can take to enforce
the above rights. For instance, if a participant requests a copy of plan
documents or the latest annual report from the Plan and does not receive them
within 30 days, he or she may file suit in a Federal court. In such a case, the
court may require the Plan administrator to provide the materials and pay up to
$110 a day until the Participant receives the materials, unless the materials
were not sent because of reasons beyond the control of the Plan administrator.
If it should happen that Plan fiduciaries misuse the Plan's money, or if a
participant is discriminated against for asserting his/her rights, you may seek
assistance from the U.S. Department of Labor.

Assistance with Your Questions

                  If a Plan participant has any questions about your Plan, he or
she should contact the Plan administrator. If a participant should have any
questions about this statement or about his/her rights under ERISA, or if he or
she needs assistance in obtaining documents from the Plan administrator, her or
she should contact the nearest office of the Pension and Welfare Benefits
Administration, U. S. Department of Labor, listed in the telephone directory or
the Division of Technical Assistance and Inquires, Pension and Welfare Benefits
Administration, U.S. Department of Labor, 200 Constitution Avenue N.W.,
Washington, D. C. 20210. He or she may also obtain certain publications about
rights and responsibilities under ERISA by calling the publications hotline or
the Pension and Welfare Benefits Administration.


                           ADMINISTRATIVE INFORMATION

Name of Plan:                     Gen-Probe Incorporated Change-In-Control
                                  Severance Compensation Plan

Plan Administrator:               Board of Directors
                                  Gen-Probe Incorporated
                                  10210 Genetic Center Drive
                                  San Diego, California 92121
                                  (858) 410-8918

Type of Administration:           Self-Administered

Type of Plan:                     Severance Pay Employee Welfare Benefit Plan

Employer Identification Number:   33-0044608

Direct Questions Regarding the
Plan to:                          Board of Directors
                                  Gen-Probe Incorporated
                                  10210 Genetic Center Drive
                                  San Diego, California 92121
                                  Attn: General Counsel
                                  (858) 410-8918

Agent for Service of Legal
Process:                          Board of Directors
                                  Gen-Probe Incorporated
                                  10210 Genetic Center Drive
                                  San Diego, California 92121
                                  Attn: General Counsel
                                  (858) 410-8918

Plan Year:                        Calendar Year

Plan Number:                      _____________________



                                      B-2