Exhibit 10.37
                    AMENDMENT TO WARRANT CERTIFICATE NO. W-1

         AMENDMENT,  dated as of October 2, 1996 (the  "Amendment"),  to Warrant
Certificate  No. W-1 dated as of October  5, 1995 (the  "Warrant  Certificate"),
between DIANON Systems,  Inc., a Delaware corporation (the "Company"),  and G.S.
Beckwith Gilbert, or registered assigns ("Mr. Gilbert").

         WHEREAS, pursuant to a Stock and Warrant Purchase Agreement dated as of
October 4, 1995 among the Gilbert Family Trust, the G.S. Beckwith Gilbert I.R.A.
Contributory  Account,  G.S.  Beckwith  Gilbert and the Company  (the  "Purchase
Agreement"), the Company issued to the Purchasers (as defined therein) 1,000,000
shares of the  Company's  Common  Stock and the  Warrants  (as defined  therein)
evidenced by the Warrant Certificate.

         WHEREAS,  the Warrant  Certificate  specifies  the terms upon which the
Warrants may be exercised.

         WHEREAS,  the  Company  and Mr.  Gilbert  desire to amend  the  Warrant
Certificate  to change the last date on which  Warrants  can be  exercised at an
exercise  price  of  $5.00 to a date  subsequent  to the  vote of the  Company's
shareholders  on  approval  of a proposed  increase  in the voting  power of the
Purchasers  (as defined in the  Purchase  Agreement)  to 20% of the total voting
power of the Company's voting securities.

         WHEREAS, such amendment reflects the parties' intentions at the time of
issuance of the Warrant  Certificate  that Mr. Gilbert would have the benefit of
the knowledge of the outcome of such vote prior to the aforesaid exercise date.

         NOW, THEREFORE,  in consideration of the premises and mutual agreements
set  forth  in the  Purchase  Agreement  and this  Amendment,  the  receipt  and
sufficiency  of  which is  hereby  acknowledged,  the  parties  hereby  agree as
follows:

         1. The second  paragraph  of Section 1 of the  Warrant  Certificate  is
amended to read in its entirety as follows:




                  "The registered  holder hereof shall have (a) the right at any
         time prior to  November  1, 1996 to elect that the  Expiration  Date of
         some or all of the Warrants  evidenced hereby shall be November 1, 1996
         rather  than  October  4,  1997 and (b) upon such  election,  the right
         thereafter  until 5:00 p.m., New York City time, on October 31, 1996 to
         exercise  such  Warrants at an exercise  price of $5.00  (increased  or
         decreased, as the case may be, to reflect the effect of each adjustment
         made,  at any  time  prior  to such  exchange,  to the  Exercise  Price
         pursuant to Section 2 as if the Exercise Price of this Warrant had been
         $5.00 since the date  hereof).  Upon such  election,  the Company shall
         extinguish,  as an  adjustment  to the  purchase  price  paid  for such
         Warrants,  for each such Warrant for which such election has been made,
         $0.37 of the  Principal  Amount (as  defined in the Note) due under the
         Note upon payment of the interest due on such  extinguished  amount for
         the  period  from  the date of this  Warrant  Certificate  through  and
         including  the  earlier  of the date of such  election  and  October 4,
         1996."

         2. This Amendment may be executed in  counterparts,  each ofwhich shall
be an original,  but all of which  together  shall  constitute  one and the same
instrument.

         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the day and year first above written.


                                DIANON SYSTEMS, INC.


                                By:   /s/Richard A. Sandberg
                                   ----------------------------------
                                Name:  Richard A. Sandberg
                                Title: President, Chairman and Chief
                                       Executive Officer



                                G.S. Beckwith Gilbert


                                /s/ G. S. Beckwith Gilbert
                                --------------------------