Exhibit 10.27


                      FOURTH MODIFICATION OF LOAN AGREEMENT


THIS FOURTH MODIFICATION is made as of this 20th day of April, 2000, by and
between IMMUCOR, INC., a Georgia corporation ("Borrower"), and WACHOVIA
BANK, N.A., a national banking association ("Lender").

                               Statement of Facts

                  Lender  and   Borrower   are  parties  to  that  certain  Loan
Agreement, dated as of October 27, 1998, as modified and amended by that certain
First Modification of Loan Agreement, dated as of April 30, 1999, and as further
modified  and amended by that certain  Second  Modification  of Loan  Agreement,
dated as of December 10,  1999,  and as further  modified by that certain  Third
Modification  of Loan  Agreement,  dated as of  December  20,  1999  (the  "Loan
Agreement"),  pursuant to which Lender has agreed to make one or more loans from
time to time to the  Borrower  in  accordance  with  the  terms  and  conditions
thereof.  Lender and  Borrower  desire to modify the Loan  Agreement  in certain
additional  respects,  all in  accordance  with and  subject  to the  terms  and
conditions set forth herein.

                  NOW,  THEREFORE,   in  consideration  of  the  premises,   the
covenants  and  agreements   contained  herein,  and  other  good  and  valuable
consideration,  the  receipt  and  adequacy  of which are  hereby  acknowledged,
Borrower and Lender do hereby agree that all capitalized terms used herein shall
have the meanings  ascribed  thereto in the Loan Agreement  (except as otherwise
expressly defined or limited herein) and do hereby further agree as follows:

                               Statement of Terms

1. Amendments of Loan Agreement. Subject to the fulfillment of the
conditions precedent to the effectiveness of this Fourth Modification which
are set forth below, the Loan Agreement shall be amended from and after
this date as follows:

     (a) The Loan  Agreement is hereby  amended by adding each of the  following
     definitions to Section 1.1 thereof in the appropriate alphabetical order:


          "Fourth  Additional  Term  Loans"  shall  mean the  term  loans in the
     aggregate  principal  amount of $5,000,000 to be made by Lender to Borrower
     pursuant to the provisions of Section 2.1.6.

          "Fourth  Additional Term Loan Commitment" shall mean the Commitment of
     Lender to make the Fourth  Additional Term Loans pursuant to Section 2.1.6,
     which Commitment shall be in the initial amount of $5,000,000 as reduced by
     the amount of each Fourth Additional Term Loan that is made.

          "Fourth  Additional Term Loan Commitment  Termination Date" shall mean
     May 31, 2001.

          "Fourth  Additional  Term Note" shall mean the term  promissory  note,
     dated April 20, 2000, as amended or supplemented  from time to time, in the
     stated  principal  amount equal to the initial Fourth  Additional Term Loan
     Commitment,  together with any renewals or extensions  thereof, in whole or
     in part.

          "Fourth Modification  Effective Date" shall mean the date on which all
     of the  conditions  precedent to the  effectiveness  of that certain Fourth
     Modification  of Loan  Agreement,  dated as of April 20, 2000,  between the
     Borrower and the Lender, have been satisfied.

     (b) The Loan  Agreement is hereby amended by amending each of the following
     definitions in Section 1.1 to read as follows:


          "Loans" shall mean the Advances under the Line of Credit together with
     the Acquisition Term Loans, the Additional Term Loans, the Third Additional
     Term Loan, and the Fourth Additional Term Loans.

          "Notes" shall mean,  collectively,  the Master Note,  the  Acquisition
     Term Note, the Additional  Term Note, the Third  Additional  Term Note, and
     the Fourth Additional Term Note.

          "Term Loans" shall mean the Acquisition Term Loans, and the Additional
     Term Loans, the Third Additional Term Loan, and the Fourth  Additional Term
     Loans.

     (c) The Loan  Agreement is hereby  amended by adding the following  Section
     2.1.6 thereto:

                           2.1.6 Fourth Additional Term Loans. During the period
         from the Fourth Modification Effective Date until the Fourth Additional
         Term Loan  Commitment  Termination  Date,  and subject to the terms and
         conditions  of  this  Agreement,  Lender  agrees  to  make  the  Fourth
         Additional Term Loans to Borrower,  the proceeds of which shall be used
         by Borrower solely to finance the repurchase of the outstanding  common
         stock of the  Borrower as  permitted  by Section  5.5 hereof.  Lender's
         commitment  hereunder to make the Fourth Additional Term Loans shall be
         reduced by the amount of each Borrowing thereof.  The Debt arising from
         the making of the Fourth  Additional  Term Loans shall be  evidenced by
         the Fourth  Additional  Term Note,  which shall be executed by Borrower
         and delivered to Lender on the Fourth Modification  Effective Date. The
         principal amount of the Fourth Additional Term Loans shall be repaid by
         the Borrower in installments as provided in the Fourth  Additional Term
         Note. In any event on June 1, 2006, the entire unpaid principal balance
         of the Fourth  Additional  Term Loans  together  with all  accrued  but
         unpaid  interest  thereon shall be due and payable in full.  The Fourth
         Additional  Term Loans  shall bear  interest  at the  Applicable  Rate,
         calculated and payable in the manner  described in Section 2.2.1,  from
         the date thereof on the unpaid  principal  amount  thereof from time to
         time outstanding.  The Fourth Additional Term Loans may be prepaid,  in
         whole  or in  part,  by  Borrower  at any  time  or  from  time to time
         hereafter; provided, however, that any partial prepayment of the Fourth
         Additional  Term Loans shall be applied by Lender in the inverse  order
         of  the  maturities  of  the  principal   installments  of  the  Fourth
         Additional Term Loans then remaining to be paid.

     (d) The Loan  Agreement is hereby amended by amending  Section  2.2.1(c) to
     read as follows:

                  (c)  Conditions  and  Limitations  on  LIBOR  Borrowings.  All
         Borrowings  obtained on the Closing  Date and for a period of three (3)
         Business  Days  thereafter  shall  be  Prime  Borrowings.   Thereafter,
         Borrower shall have the continuing right, provided that with respect to
         Borrowings  other  than  the  Third  Additional  Term  Loan no Event of
         Default or Default  Condition  exists,  to obtain  Borrowings which are
         LIBOR  Borrowings or to convert Prime  Borrowings to LIBOR  Borrowings;
         subject,  however,  to the following  conditions and  limitations:  (i)
         Borrower must request a LIBOR Borrowing,  specifying the amount thereof
         and the applicable Interest Period, at least three (3) Business Days in
         advance of the  intended  borrowing  date;  (ii) no more than three (3)
         LIBOR  Borrowings  under  each of the Line of Credit and the Term Loans
         (other  than the Third  Additional  Term Loan) may be  obtained  at any
         time;  (iii) LIBOR  Borrowings  (other than the Third  Additional  Term
         Loan)  must be in  minimum  amounts of Five  Hundred  Thousand  Dollars
         ($500,000), or integral multiples thereof, (iv) the Interest Period for
         LIBOR  Borrowings in respect of the Line of Credit shall not exceed the
         Termination  Date; (v) the Interest  Periods for, and aggregate  amount
         of,  LIBOR  Borrowings  in  respect  of any of the Term  Loans  must be
         consistent with, and not exceed, the scheduled  principal  amortization
         thereof;  or (vi)  if on or  prior  to the  first  day of any  Interest
         Period, Lender determines that deposits in United States Dollars or Cn.
         Dollars  (in the  applicable  amounts)  are not  being  offered  in the
         relevant  market for such  Interest  Period or that the LIBOR Rate will
         not  adequately  and fairly  reflect  the cost to Lender of funding any
         relevant  borrowings  for such  Interest  Period,  then,  Lender  shall
         forthwith  give notice  thereof to  Borrower,  whereupon,  until Lender
         notifies Borrower that the circumstances giving rise to such suspension
         no longer  exist,  the  obligation  of Lender to make LIBOR  Borrowings
         available to Borrower  shall be suspended and with respect to the Third
         Additional Term Loan the Lender shall designate a substitute  index for
         calculation of the interest rate which  adequately and fairly  reflects
         the cost to Lender of funding and maintaining the Third Additional Term
         Loan;  (vii) if, at any time, a change of law, or  compliance by Lender
         with any request or directive  (whether or not having the force of law)
         of any  governmental  authority shall make it unlawful or impracticable
         for Lender to make  available,  maintain or fund any LIBOR  Borrowings,
         Lender  shall  forthwith  give  notice  to  such  effect  to  Borrower,
         whereupon, until Lender notifies Borrower that the circumstances giving
         rise to such  suspension no longer exist,  the  obligation of Lender to
         make such  Borrowings  available to Borrower  shall be suspended and if
         Lender shall  determine  that it may not lawfully  continue to maintain
         and fund any then  outstanding  Borrowings  to  maturity  and  shall so
         specify in such notice, each Borrowing, other than the Third Additional
         Term  Loan,  so  affected  shall  be  converted  to a  Prime  Borrowing
         effective immediately and the Third Additional Term Loan shall from the
         date  of  such  notice  bear  interest  at an rate  equal  to an  index
         designated  by the Lender plus the  Applicable  Margin;  (viii)  unless
         Borrower has timely given Lender a notice of LIBOR  Borrowing  required
         hereinabove,  a LIBOR Borrowing  (other than the Third  Additional Term
         Loan) shall automatically  convert to Prime Borrowing at the expiration
         of  the  Interest  Period  corresponding  thereto;  (ix)  no  voluntary
         prepayment of any LIBOR Borrowing shall be permitted  unless Lender has
         given its written consent thereto;  and (x) upon the request of Lender,
         delivered  to  Borrower,  Borrower  shall pay to Lender  such amount or
         amounts  as  shall be  determined  by  Lender  in  connection  with the
         relevant  Interest Period as a result of: (A) any payment or prepayment
         of any LIBOR Borrowing by Borrower on a date other than the last day of
         an Interest Period for such Borrowing, whether as a result of voluntary
         prepayment,   mandatory   prepayment,   involuntary   acceleration   or
         otherwise;  or (B) any failure by the  Borrower to  undertake  any such
         LIBOR  Borrowing  on the date for  which  notice of such  Borrowing  is
         specified  by  Borrower.  In the case of  clause  (x),  such sum  shall
         include, without limitation,  an amount equal to the excess, if any, of
         the amount of interest  which would have  accrued on the amount so paid
         or prepaid or not prepaid or  borrowed  for the period from the date of
         such payment, prepayment or failure to prepay or borrow to the last day
         of the then current Interest Period for such Borrowing (or, in the case
         of a  failure  to  prepay  or  borrow,  the  Interest  Period  for such
         Borrowing  which would have  commenced  on the date of such  failure to
         prepay or borrow) at the applicable rate of interest for such Borrowing
         provided  for herein  over the amount of  interest  (as  determined  by
         Lender in the reasonable  exercise of its discretion) Lender would have
         paid on deposits in United States Dollars of comparable  amounts having
         terms  comparable to such period placed with it by leading banks in the
         London interbank market.

     (e) The Loan Agreement is hereby amended by adding the following at the end
     of Section 2.2.2 (b) thereof:


                  As  additional  compensation  for  Lender's  making the Fourth
         Additional Term Loan Commitment  available to Borrower,  Borrower shall
         pay  Lender,  in  arrears,  on each  Payment  Date  prior to the Fourth
         Additional  Term  Loan  Commitment  Termination  Date as well as on the
         Fourth  Additional  Term  Loan  Commitment  Termination  Date,  a fully
         earned,  non-refundable  fee for Borrower's  non-use of available funds
         under the Fourth  Additional Term Loan Commitment in an amount equal to
         three-eighths  of one percent  (0.375%)  per annum  (calculated  on the
         basis of a 360-day year for actual days elapsed) of the average  unused
         amount  of  the  Fourth   Additional   Term  Loan  Commitment  for  the
         consecutive three month period ending on the day immediately  preceding
         such Payment Date.


     (f) The Loan  Agreement is hereby  amended by amending the last sentence of
     Section 2.4 to read as follows:


          Any  prepayment  made by  Borrower  under  this  Section  2.4 shall be
     applied,  first,  to  prepay  the  scheduled  installments  of  the  Fourth
     Additional  Term Loans in inverse order of maturity  until such Loans shall
     have been prepaid in full, second, to prepay the scheduled  installments of
     the Third  Additional  Term Loan in inverse  order of  maturity  until such
     Loans have been prepaid in full, third to prepay the scheduled installments
     of the Additional  Term Loans in inverse order of maturity until such Loans
     have been prepaid in full, and fourth to prepay the scheduled  installments
     of the Acquisition Term Loans in inverse order of maturity until such Loans
     have been prepaid in full.

2. No Other Amendments. Except for the amendments expressly set forth and
referred to in Sections 1 above, the Loan Agreement shall remain unchanged
and in full force and effect. Nothing in this Fourth Modification is
intended, or shall be construed, to constitute a novation or an accord and
satisfaction of any of the Borrower's indebtedness or other indebtedness to
the Lender under or in connection with the Loan Agreement (collectively,
the "Obligations") or to modify, affect or impair the perfection or
continuity of Lender's security interests in, security titles to or other
liens on any collateral for the Obligations.

3. Representations and Warranties. To induce Lender to enter
into this Fourth Modification, the Borrower does hereby warrant, represent and
covenant to Lender that: (a) each representation or warranty of the Borrower set
forth in the Loan Agreement is hereby restated and reaffirmed as true and
correct on and as of the date hereof as if such representation or warranty were
made on and as of the date hereof (except to the extent that any such
representation or warranty expressly relates to a prior specific date or
period), and no Default or Event of Default has occurred and is continuing as of
this date under the Loan Agreement as amended by this Fourth Modification; and
(b) Borrower has the power and is duly authorized to enter into, deliver and
perform this Fourth Modification and this Fourth Modification is the legal,
valid and binding obligation of Borrower enforceable against it in accordance
with its terms.

4. Conditions Precedent to Effectiveness of this Fourth
Modification. The effectiveness of this Fourth Modification and the amendments
provided herein are subject to the truth and accuracy in all material respects
of the representations and warranties of the Borrower contained in Section 3
above and to the fulfillment of the following additional conditions precedent:
(a) Lender shall have received one or more counterparts of this Fourth
Modification duly executed and delivered by the Borrower; (b) if and to the
extent required by Lender, any and all guarantors of the Obligations shall have
consented to the execution, delivery and performance of this Fourth Modification
and all of the transactions contemplated hereby by signing one or more
counterparts of this Fourth Modification in the appropriate space indicated
below and returning same to Lender; (c) Lender shall have received the Fourth
Additional Term Note, dated as of the date of this Fourth Modification and
having a stated principal amount equal to $5,000,000, duly executed and
delivered, as well as a closing certificate of Borrower and an opinion of
Borrower's counsel (both in form and substance satisfactory to Lender) with
respect to this Fourth Modification and the Fourth Additional Term Note; and (d)
Lender shall have received payment from Borrower of a closing fee for this
Fourth Modification in the amount of $25,000, which shall be fully earned and
non-refundable upon payment thereof.

5. Counterparts. This Fourth Modification may be executed in multiple
counterparts, each of which shall be deemed to be an original and all of
which when taken together shall constitute one and the same instrument.

6. Governing Law. This Fourth Modification shall be governed by, and
construed in accordance with, the internal laws of the State of Georgia
applicable to contracts made and performed in such state.


<PAGE>



                  IN WITNESS WHEREOF, the parties hereto have caused this Fourth
Modification  to be duly executed and delivered as of the day and year specified
at the beginning hereof.

                                      BORROWER:

                                      IMMUCOR, INC.


                                      By: /s/  Edward L. Gallup
                                      Edward L. Gallup, President


                                      LENDER:

                                      WACHOVIA BANK, N.A.


                                      By:      /s/  Ernesto Moran
                                      Title:   President



<PAGE>


                                               CONSENT OF GUARANTORS


                  Each of the undersigned  guarantors does hereby consent to the
execution,   delivery  and  performance  of  the  within  and  foregoing  Fourth
Modification of Loan Agreement.

                  IN WITNESS  WHEREOF,  each of the  undersigned  guarantors has
executed this Consent under seal as of the day and year first above set forth.


                                        GAMMA BIOLOGICALS, INC.



                                        By: /s/  Edward L. Gallup
                                        Edward L. Gallup, President


                                        GAMMA BIOLOGICALS INTERNATIONAL, INC.


                                        By: /s/  Edward L. Gallup
                                        Edward L. Gallup, President


                                        BCA ACQUISITION CORPORATION


                                        By: /s/  Edward L. Gallup
                                        Edward L. Gallup, President