Exhibit 10.35


         THIS  AGREEMENT,  effective  this  3rd day of  December,  1996,  by and
between   DIANON   SYSTEMS,   INC.  (the   "COMPANY")  and  KEVIN  JOHNSON  (the
"EXECUTIVE").

                                WITNESSETH THAT:


         WHEREAS,  the  EXECUTIVE is employed by the COMPANY as President and is
an integral part of its  management  team and a key  participant in the decision
making process relative to short-term and long-term  planning and policy for the
COMPANY.


         WHEREAS,  as an inducement to commence his employment with the COMPANY,
the EXECUTIVE requested the COMPANY to make a personal loan to him;


         WHEREAS,  the COMPANY  wishes to encourage  the  EXECUTIVE to begin and
continue in his employment  with the COMPANY and the EXECUTIVE  wishes to remain
an employee of the COMPANY; and


         NOW,  THEREFORE,  it is hereby agreed by and between the parties hereto
as follows:

         1. Term of Loan Agreement

         This  Agreement  shall be  effective  as of the date above  written and
shall  continue  thereafter  until  the  first to  occur of (i) the  EXECUTIVE's
termination of employment with the COMPANY, or (ii) December 31, 2002.

         2. Loan Agreement

         (a) The COMPANY will advance to EXECUTIVE  one hundred  fifty  thousand
dollars ($150,000) on December 3, 1996

         (b)  EXECUTIVE  will pay  interest on the loan  annually at the rate of
6.6% per annum or the Internal Revenue Service standard,  whichever is less, and
the COMPANY  will pay  EXECUTIVE,  in addition to salary,  amounts  equal to the
interest paid by EXECUTIVE during his employment with the COMPANY.

         (c)  EXECUTIVE may repay all or any portion of the advance at any time.
If at any time during this Agreement the EXECUTIVE's employment with the COMPANY
is  terminated,  any unrepaid  portions of the advance  will become  immediately
repayable  on  the  date  the  EXECUTIVE's  employment  is  terminated,   unless
termination is by the COMPANY  without stated cause as described in Paragraph 10
of the  Employment  Agreement  entered by the  parties on May 3, 1996,  in which
case,  unrepaid  portions of the advance will become  payable one year after the
termination  date.  At the end of each full  month in the period  commencing  in
January, 1996 and ending December, 2002 in which EXECUTIVE's employment with the
COMPANY  continues  without  notice of intent to terminate  having been given by
EXECUTIVE or the COMPANY, the COMPANY shall forgive $2,500 of the advance.

         3. Income Tax Withholding and Reporting

         The COMPANY shall withhold all Federal,  State or other taxes as may be
required pursuant to any law or governmental  regulation or ruling.  The COMPANY
shall  report  as income to  EXECUTIVE  all  imputed  income  amounts  as may be
required pursuant to any Federal, State or other law or governmental  regulation
or ruling.



         4. Wage Deduction Authorization

         EXECUTIVE agrees to execute any authorization necessary for the COMPANY
to achieve repayment through payroll deduction.

         5. No Right to Continue Employment; Employment at Will

         Nothing  contained in the Agreement  will confer upon the EXECUTIVE any
right to continued  employment  with the COMPANY,  nor shall limit the COMPANY's
right to terminate the EXECUTIVE's employment at will.

         6. Entire Understanding

         This Agreement  contains the entire  understanding  between the COMPANY
and the EXECUTIVE with respect to the loan  described  herein and supersedes any
prior agreement between the COMPANY and the EXECUTIVE.

         7. Severability

         If for any  reason,  any one or  more  of the  provisions  or part of a
provision  contained in this Agreement  shall be held to be invalid,  illegal or
unenforceable  in any respect,  such  invalidity,  illegality or  enforceability
shall not affect any other  provision or part of a provision  of this  Agreement
not held so invalid, illegal or unenforceable,  and each other provision or part
of a provision  shall to the full extent  consistent  with law  continue in full
force and effect.

         8. Binding Agreement

         This  Agreement  shall be binding upon,  and shall inure to the benefit
of, the EXECUTIVE and the COMPANY and their respective  permitted successors and
assigns.

         9. Modification

         This  Agreement may not be modified or amended  except by an instrument
in writing signed by the parties hereto.

         10. Headings of No Effect

         The paragraph  headings contained in this Agreement are included solely
for  convenience  of  reference  and shall not in any way affect the  meaning or
interpolation of any provisions of this Agreement.

         11. Governing Law

         This  Agreement  and its  validity,  interpretation,  performance,  and
enforcement  shall be governed by the laws of the State of  Connecticut  without
giving effect to the choice of law provisions in effect in such State.




         IN WITNESS  WHEREOF,  the  COMPANY  has  caused  this  Agreement  to be
executed by its officer thereunto duly authorized,  and the EXECUTIVE has signed
this  Agreement,  all  effective  as of the date  first  above  written.


                                          DIANON SYSTEMS, INC.


                                          By:  /s/Richard A. Sandberg
                                               ----------------------------
                                                   Chairman


                                          KEVIN JOHNSON


                                          /s/Kevin Johnson
                                          ---------------------------------