Exhibit 10.318

***Certain
information on this page has been omitted and filed separately with the Commission. Confidential treatment has been requested with respect to the omitted portions.

CERTAIN MATERIAL (INDICATED BY AN ASTERISK) HAS BEEN OMITTED FROM THIS DOCUMENT PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT. THE OMITTED MATERIAL HAS BEEN FILED SEPARATELY
WITH THE SECURITIES AND EXCHANGE COMMISSION.

AMENDMENT NO. 3 TO  AGREEMENT

This Amendment No. 3 ("Amendment No. 3") is entered effective April 1, 2002 (the
"Amendment Effective Date") pursuant to and amending that certain Agreement (as defined below) between Gen-Probe Incorporated, a Delaware
corporation ("Gen-Probe") and Chiron Corporation, a Delaware corporation ("Chiron"), on
behalf of itself and its Affiliates. Capitalized terms used but not defined herein shall have the meanings set forth in the Agreement.

Recitals

A.
The parties entered into the Agreement as of June 11, 1998 pursuant to which, among other things, the parties described their respective rights and obligations with respect to
production planning and
inventory management processes. The Agreement was amended by the following: (i) June 11, 1998 Collaboration Agreement, (ii) June 11, 1998 Supplemental letter agreement,
(iii) June 26, 1998 Addendum to Collaboration Agreement, (iv) June 30, 1998 Supplemental letter agreement, (v) June 30, 1998 Consent,
(vi) December 1, 1998 letter agreement re American Red Cross revenues, (vii) December 7, 1999 First amendment to Collaboration Agreement, (viii) February 1,
2000 Second amendment to Collaboration Agreement, (ix) June 7, 2001 Supplemental agreement no. 1 (Customer training and Support), (x) October 30, 2001
Confidentiality and Joint Interest Agreement, (xi) April 4, 2001 Agreement re Arbitration. In addition, the parties entered into that certain Definitive Written Settlement Agreement
dated December 4, 2001 (the "Settlement Agreement").

B.
The parties have discussed a proposed revision to and clarification of their respective rights and obligations with respect to production planning and inventory management processes,
and have agreed to make certain additional changes to the Agreement in connection therewith, in accordance with the provisions of this Amendment No. 3.

C.
By this Amendment No. 3, the parties desire to revise and clarify their respective rights and obligations, as described herein, applicable to all Blood Screening Assays,
including one or more Future Blood Screening Assays to be conducted by the Blood Screening Instruments to be developed under the terms of the Agreement.

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Agreement

NOW, THEREFORE, for and in consideration of the mutual covenants and agreements set forth in this Amendment No. 3, the parties agree as follows:

1.Definitions.



2.Forecasts And Orders.    Section 6.3 of the Agreement and its associated
subsections are hereby deleted and replaced in their entirety with the following:



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3

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3.Delivery. Section 6.4.1 of the Agreement is hereby deleted and replaced in its entirety by
the following:



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4.Warehousing. The following new Section 6.4.4 is hereby added to the end of
Section 6.4 of the Agreement:



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5.Insurance Certificates.



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6.Inventory Management. The following new Section 6.4.5 is hereby added to the end of
Section 6.4, following newly added Section 6.4.4:



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7.Safety Stocks. Section 6.12 (Safety Stocks) is hereby deleted and replaced, in its
entirety, as follows:



8.Scope of Amendment No. 3. The parties hereto agree that the Forecasts and Orders provisions
set forth in Section 2 of this Amendment No. 3 address the rights and obligations of each party with respect to Lot 13 and subsequent Lots. Except as expressly stated herein, nothing in
Section 2 of this Amendment
No. 3 shall apply in any respect to the rights or obligations of the parties with respect to Lots 1-12. Accordingly, and for ease of implementation, the parties agree that the
Forecast and Orders provisions set forth in Section 2 will apply commencing with and applying to the Forecast due April 1, 2002 from Chiron (covering the 12 months ending
April 30, 2003). Notwithstanding the above, the Order Processing provisions of new Section 6.3.6 shall govern the rights and obligations of each party from and after the Amendment
Effective Date. Except as set forth in this Section 8, from and after the Amendment Effective Date, this Amendment No. 3 shall apply in all respects to the Agreement.

9.Limited Terms Applicable to [***]. The parties agree to equally share the
"variable manufacturing cost" of those portions of [***] held in inventory by Gen-Probe and Chiron that are unsold, not retained for R&D or other internal purpose
by either party and scrapped due to product expiration, net of the aggregate purchase price previously paid by Chiron to Gen-Probe for expired

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units held in Chiron's inventory. For the purpose of this Amendment No. 3, [***] will be used as the "variable manufacturing cost" to value scrap material. To the
extent necessary to avoid product outdating and if requested by Chiron, Gen-Probe agrees to re-label, at Gen-Probe's expense and in accordance with all
international and domestic labeling requirements, such Blood Screening Assays in [***] that may be relabeled with twenty-four (24) month expiration dates.

10.Effect of Amendment No. 3 on Supplemental Agreement. As of the Amendment Effective Date,
the Supplemental Agreement shall terminate in all respects. Each party's obligations under such Supplemental Agreement shall terminate as of such date; provided, however, that such termination shall
not act to bar claims under the terms of the Supplemental Agreement that arose prior to such Amendment Effective Date.

11.No Other Amendment. Except as is expressly set forth in this Amendment No. 3, all other
terms and conditions of the Agreement and the Settlement Agreement are hereby ratified and shall continue in full force and effect.

12.Counterparts. This Amendment No. 3 may be executed in counterparts, each of which shall be
deemed an original, and all of which together shall constitute one and same instrument.

IN
WITNESS WHEREOF, the parties have caused this Amendment No. 3 to be executed as of April 1, 2002 and the persons signing below warrant that they are duly authorized to
sign for and on behalf of the respective parties.

|Gen-Probe:                                      |  | Chiron:                                           
|----------------------------------------------- |  | --------------------------------------------------
|GEN-PROBE INCORPORATED,                         |  | CHIRON CORPORATION                                
|a Delaware corporation                          |  | a Delaware corporation                            
|By /s/HENRY L. NORDHOFF                         |  | By /s/ WILLIAM G. GREEN                           
|Henry L. Nordhoff                               |  | William G. Green                                  
|President and Chief Executive Officer           |  | Senior Vice President and President, Blood Testing
|[SEAL]
[which reads:
APPROVED
Bowen
Legal Dept] |  |                                                   

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Schedule A.1    Labeling Requirements

|Part Number |  | Description |  | Label Options
|----------- |  | ----------- |  | -------------
|[***]       |  | [***]       |  | [***]        

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Schedule A.2    Standing Agenda for Production Planning Meetings

Purpose:

Review
Forecast and production plan and make the appropriate production planning and inventory management decisions to meet Customer supply needs in a cost efficient manner.

Agenda:

    Review
previous month performance

    Shipments

    Inventory

    Production

    Delivery

    Review
current Forecast and production plan

    [***]

    Timing/feasibility
for next production?

    "What
If analysis"Risk and risk management discussion

    Outstanding
issues [***]

    Review
Plan and Key Decisions.

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Schedule A.3    Sample Purchase Order

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|                                                                                                      |  | CHIRON                                                                                                                                      
|----------------------------------------------------------------------------------------------------- |  | --------------------------------------------------------------------------------------------------------------------------------------------
|Purchase order                                                                                        |  | Supplier:                                                                                                                                   
|P.O. # 45059813Order Date: 21-May-2002
Buyer: Mary Semeniuk
Phone #: 510-923-6010
Fax #: 510-923-3340 |  | GEN-PROBE INCORPORATED
10210 GENETIC CENTER DRIVE
SAN DIEGO CA 92121
Vendor Contact: SHERYL STILES
Phone #: 858-410-8984
Fax #: 800-288-3141

A
copy of this purchase order was faxed to Sheryl Stiles at Gen-Probe.

Equal
Opportunity Contract Clause (EOC)
Chiron Corporation is committed to the provisions outlined in the Equal Opportunity Clauses of Executive Order 11246, (60-1.4), Section 503 of the Rehabilitation Act of 1973,
(60-741.5), and, Section 402 of the Vietnam Veterans Readjustment Act of 1974, (60-250.4), As well as any other regulations pertaining to these orders.

Please
fax a copy of the packing list to Erica Artis at Chiron Corp at 510-923-2786.

|Item # |  | QTY/UOM |  | Chiron Mat #
Vendor Mat #
Material Description                   |  | Price        |  | Extended Price
|------ |  | ------- |  | ---------------------------------------------------------------- |  | ------------ |  | --------------
|1      |  | 170 EA  |  | [***]
301030-PROCLEIX (TM) 5000 IVD TEST KIT
[***]
[***]         |  | [***] per EA |  | [***]         
|2      |  | 35 EA   |  | [***]
301031
301031-PROCLEIX (TM), 1000 IVD TEST KIT
[***]
[***] |  | [***] per EA |  | [***]         
|3      |  | 885 EA  |  | [***]
301027-PROCLEIX (TM), ASSAY FLUIDS, IVD
[***]
[***]        |  | [***] per EA |  | [***]         
|4      |  | 443 EA  |  | [***]
301038-PROCLEIX (TM), AUTO DETECT, IVD
[***]
[***]         |  | [***] per EA |  | [***]         

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|                                                                                                      |  | CHIRON                                                                                                                                      
|----------------------------------------------------------------------------------------------------- |  | --------------------------------------------------------------------------------------------------------------------------------------------
|Purchase order                                                                                        |  | Supplier:                                                                                                                                   
|P.O. # 45059813Order Date: 21-May-2002
Buyer: Mary Semeniuk
Phone #: 510-923-6010
Fax #: 510-923-3340 |  | GEN-PROBE INCORPORATED
10210 GENETIC CENTER DRIVE
SAN DIEGO CA 92121
Vendor Contact: SHERYL STILES
Phone #: 858-410-8984
Fax #: 800-288-3141

|Item # |  | QTY/UOM   |  | Chiron Mat #
Vendor Mat #
Material Description                |  | Price         |  | Extended Price
|------ |  | --------- |  | ------------------------------------------------------------- |  | ------------- |  | --------------
|5      |  | 575 EA    |  | [***]
301026-PROCLEIX (TM), DISCR PROBE, IVD
[***]            |  | [***] per EA  |  | [***]         
|6      |  | 60 EA     |  | [***]
301036
301036-PROCLEIX (TM), HIV-1/HCV CALIB, IVD
[***] |  | [***] per EA  |  | [***]         
|7      |  | 465 EA    |  | [***]
301035
301035-PROCLEIX (TM), HIV-1/HCV CONTR,IVD
[***]  |  | [***] per EA  |  | [***]         
|8      |  | 50 EA     |  | [***]
301034
301034-PROCLEIX (TM), PROF PANELS, IVD
[***]     |  | [***] per EA  |  | [***]         
|9      |  | 885 CAS   |  | [***]
GP
TU0022-TEN TUBE UNIT (TTU), ESAS
[***]               |  | [***] per CAS |  | [***]         
|10     |  | 885 CAS   |  | [***]
GP
104578-TEN TUBE CASSETTE (TTC)
[***]                 |  | [***] per CAS |  | [***]         
|11     |  | 7,630 CAS |  | [***]
GP
102085-SEALING CARDS (35/PKG)
[***]                  |  | [***] per CAS |  | [***]         
|12     |  | 38 EA     |  | [***]
[***]
[***]                                             |  | [***] per EA  |  | [***]         

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|                                                                                                      |  | CHIRON                                                                                                                                      
|----------------------------------------------------------------------------------------------------- |  | --------------------------------------------------------------------------------------------------------------------------------------------
|Purchase order                                                                                        |  | Supplier:                                                                                                                                   
|P.O. # 45059813Order Date: 21-May-2002
Buyer: Mary Semeniuk
Phone #: 510-923-6010
Fax #: 510-923-3340 |  | GEN-PROBE INCORPORATED
10210 GENETIC CENTER DRIVE
SAN DIEGO CA 92121
Vendor Contact: SHERYL STILES
Phone #: 858-410-8984
Fax #: 800-288-3141

|Item # |  | QTY/UOM |  | Chiron Mat #
Vendor Mat #
Material Description |  | Price |  | Extended Price
|------ |  | ------- |  | ---------------------------------------------- |  | ----- |  | --------------
|       |  |         |  | [***]                                          |  |       |  |               
|       |  |         |  | Total Net Item Value Excluding Tax             |  |       |  | [***] USD     

|                                                                                                            |  |                                                                                                       
|----------------------------------------------------------------------------------------------------------- |  | ------------------------------------------------------------------------------------------------------
|                                                                                                            |  |                                                                                                       
|Free on board SHIPPING POINT
Shipment Terms: Within 30 days Due net                                         |  |                                                                                                       
|Remit To:                                                                                                   |  | Deliver To:                                                                                           
|Chiron Corporation
Accounts Payable Department
4560 Horton Street
Emeryville, CA 94608
Attn: P.O.# 45059813 |  | Chiron Warehouse
C/O Gen-Prove Incorporated
10808 Willow Court
San Diego CA 92127
Attn: P.O.# 45059813

|                          |  |                               |  |                      |  |                             
|------------------------- |  | ----------------------------- |  | -------------------- |  | ----------------------------
|Supplier Confirmation By: |  |                               |  | For Chiron Corp. By: |  |                             
|                          |  |                               |  |                      |  |                             
|(If Requested)            |  | Authorized Agent, Title, Date |  |                      |  | Authorized Agent, Title Date

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Schedule A.4    List of Warehousing Facilities

[***]

[***]

[***]

***Certain
information on this page has been omitted and filed separately with the Commission. Confidential treatment has been requested with respect to the omitted portions.

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