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                                                                 EXHIBIT 10.19.1

November 8, 2002

Mr. Thomas H. Trobaugh
2075 Compton Way
Alpharetta, Georgia 30022

Dear Tom:

As we discussed on November 4, 2002, we have determined that your employment
with Serologicals Corporation will be terminated effective November 4, 2002 (the
"Termination Date"). You should promptly begin efforts to secure alternative
employment. To assist you, Serologicals will make available, at its expense,
outplacement services to you, to be provided by a professional outplacement firm
selected by us, until you find alternative employment or May 9, 2002, whichever
is earlier. Serologicals will be liable for and make payments for all fees and
expenses incurred by the outplacement firm directly to the outplacement firm.
Please contact me to make arrangements for initiation of this service. The
following sets forth our mutual commitments:

1.  Serologicals will continue to pay your base salary for a period of twelve
    months from the Termination Date, as provided for in the letter agreement
    between the Company and you dated September 19, 2001 (the "Letter
    Agreement").

2.  You shall be eligible to elect COBRA coverage and only pay an amount equal
    to the employee contribution typically paid for your type of medical, dental
    and vision coverage. Serologicals will pay the remaining costs associated
    with COBRA coverage for the twelve-month period from the Termination Date.
    Thereafter, you can continue COBRA coverage at your total cost for up to an
    additional six months.

3.  Pursuant to the terms of the Deferred Stock Unit Agreement dated March 12,
    2002 ("Deferred Stock Agreement"), which is incorporated by reference
    herein, you shall receive distribution of stock in accordance with the
    applicable terms and conditions. You shall also have the right to exercise
    any vested stock options in accordance with the terms of the Stock Option
    Agreement dated October 5, 2001 ("Option Agreement"), which is incorporated
    by reference herein.

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Mr. Thomas H. Trobaugh
November 8, 2002
Page 2

4.  In addition, Serologicals shall pay you:

         (i) Thirty-one Thousand and 16/100 Dollars ($31,016.00) as full
         satisfaction of, and as an alternative to, any obligation of
         Serologicals to provide to you (a) life and disability benefit
         coverage; (b) company matching contributions to the Serologicals 401(k)
         retirement savings plan; and (c) the loss of a tax benefit from not
         being able to defer into Serologicals 401 (k) retirement savings plan.
         These payments will be grossed-up to cover state and federal taxes.

         (ii) Nine Thousand Three Hundred Dollars ($9,300.00) as full
         satisfaction of any amounts due to you under Serologicals tuition
         reimbursement program or otherwise for education programs pursued by
         you while employed by Serologicals; and,

         (iii) One Thousand Two Hundred and Ten Dollars ($1,210.00) as full
         satisfaction for reinstatement of any frequent flyer points exercised
         by you in connection with travel scheduled to have been taken by you
         after the Termination Date, but that was booked prior to the
         Termination Date., which payment will be grossed-up to cover state and
         federal taxes.

5.  You agree to release and forever discharge the Company, its affiliated
    companies, and past and present directors, officers, owners, agents,
    employees or attorneys, from any and all actions, causes of action, asserted
    or unasserted claims and demands whatsoever, in law or in equity
    (hereinafter collectively referred to as "Claims"), whether known or
    unknown, which you may have against the Company based on any acts,
    omissions, transactions or occurrences whatsoever occurring or accruing
    prior to the date of execution of this Agreement, including, but not limited
    to: (i) claims which are related to employment with the Company and the
    termination of employment; (ii) claims for retaliatory, wrongful or
    constructive discharge, intentional or negligent infliction of emotional
    distress, outrageous conduct, invasion of privacy, assault, battery, fraud,
    breach of duty, libel, slander or tortious conduct of any kind; and/or (iii)
    all other claims arising at law or in equity.

6.  You knowingly and voluntarily waive and release any and all claims for
    damages, wages, benefits, attorneys' fees, costs or other relief against the
    Company and any and all persons acting by, through or in concert with the
    Company based upon state, federal or local statutory or common law,
    including but not limited to claims under federal and state wage and hour
    laws, the Fair Labor Standards Act of 1938 (29 U.S.C. Section 201, et seq.),
    Title VII of the Civil Rights Act of 1964, as amended (42 U.S.C. Section
    2000e, et seq.), 42 U.S.C. Section 1981, the Americans with Disabilities
    Act (42 U.S.C. Section 12101, et seq.), the Family and Medical Leave Act of
    1993 (29 U.S.C. Section 2601, et seq.), the Age Discrimination in Employment
    Act of 1967, as amended (29 U.S.C. Section 621, et seq.), the Employee
    Retirement Income Security Act of 1974 (29 U.S.C. Section 1001, et seq.),
    the Consolidated Omnibus Budget Reconciliation Act (29

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Mr. Thomas H. Trobaugh
November 8, 2002
Page 3

    U.S.C. Section 1161 et seq.), and any claims under federal, state or local
    law pertaining to employment or employment benefits, and all other claims
    of any kind based on any statute, contract, or tort theory arising out of
    any matter, act, omission, transaction, occurrence, or event that has
    occurred or is alleged to have occurred up to the date of this Agreement.
    You also agree that you will not pursue a lawsuit against the Company or any
    related entity or person or entity acting on the Company's behalf by filing
    a lawsuit in any state or federal court on account of anything which has
    occurred up to the date you sign this Agreement.

7.  Serologicals and you acknowledge and agree that you may have at least
    twenty-one (21) days after receipt of this agreement within which to review
    and consider, discuss with an attorney, and decide to execute or not execute
    this agreement; and you have seven (7) days after the execution of this
    Agreement within which to revoke this Agreement.

8.  Except for (i) paragraphs 5-8 and 10(a) - (e) of the Letter Agreement; (ii)
    the Deferred Stock Agreement; and (iii) the Option Agreement, all other
    agreements between the parties are merged into and extinguished by this
    agreement.

If you are in agreement with the terms set forth above, please sign this letter
and return it to me.

I wish you the best in your future endeavors.

Sincerely,

/s/ Robert P. Collins

Robert P. Collins
Vice President, Human Resources

                                       ACCEPTED AND AGREED:

                                       /s/ Thomas H. Trobaugh
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                                       Thomas H. Trobaugh

                                       November 18, 2002
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                                       (Date)