EXHIBIT 2.1.3

                                 AMENDMENT NO. 3

                                       TO

                          AGREEMENT AND PLAN OF MERGER

         This AMENDMENT NO. 3 TO AGREEMENT AND PLAN OF MERGER (the "AMENDMENT"),
made as of the 25th day of  August,  2005 is entered  into by and among  Xtrana,
Inc., a Delaware corporation  ("XTRANA"),  AIC Merger Corporation,  a California
corporation  and  wholly-owned  subsidiary  of  Xtrana  ("MERGERCO"),  and Alpha
Innotech Corporation, a California corporation ("AIC"). Xtrana, MergerCo and AIC
are sometimes  referred to herein  individually as a "PARTY" and collectively as
the "PARTIES."

                                    RECITALS:

         A.       The Parties have entered into that certain  Agreement and Plan
of Merger dated  December 14, 2004,  as amended by Amendment  No. 1 to Agreement
and Plan of Merger dated April 6, 2005 and Amendment No. 2 to Agreement and Plan
of Merger dated July 6, 2005 (as amended,  the "AGREEMENT"),  which provides for
the merger of AIC with and into MergerCo on the term and conditions set forth in
the Agreement.

         B.       The Parties desire to amend the provisions of the Agreement on
the terms and conditions set forth herein.

                                   AGREEMENT:

         NOW, THEREFORE,  in consideration of the  representations,  warranties,
covenants and  agreements  contained in this  Amendment,  and for other good and
valuable  consideration,   the  receipt  and  sufficient  of  which  are  hereby
acknowledged, the parties hereto agree as follows:

         1.       AMENDMENT TO SECTION 8.1.3.  Section 8.1.3 of the Agreement is
hereby amended in its entirety to read as follows:

                   "by either  Xtrana or AIC if the  Merger  shall not have been
          consummated  on or before  October 14, 2005 (other than as a result of
          the  failure  of the Party  seeking to  terminate  this  Agreement  to
          perform its obligations under this Agreement  required to be performed
          at or prior to the Effective Time);"

         2.       RATIFICATION  OF REMAINING  TERMS.  Except as set forth above,
the remaining terms and conditions of the Agreement shall not be amended by this
Amendment  and shall remain in full force and effect,  and binding in accordance
with their respective terms.





         3.       COUNTERPARTS.  This  Amendment  may be executed in two or more
counterparts, each of which shall constitute an original, but all of which, when
taken together, shall constitute one and the same instrument.

          IN WITNESS WHEREOF, the parties hereto have executed this Amendment as
of the date set forth in the first paragraph.

                                  ALPHA INNOTECH CORPORATION


                                  By:      /S/ HASEEB CHAUDHRY
                                      ----------------------------------------
                                           Name:    Haseeb Chaudhry
                                           Title:   Chief Executive Officer

                                  XTRANA, INC.


                                  By:      /S/ JAMES H. CHAMBERLAIN
                                      ----------------------------------------
                                           Name:    James H. Chamberlain
                                           Title:   Chief Executive Officer

                                  AIC MERGER CORPORATION


                                  By:      /S/ JAMES H. CHAMBERLAIN
                                      ----------------------------------------
                                           Name:    James H. Chamberlain
                                           Title:   President


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