SECURITIES AND EXCHANGE COMMISSION

                            Washington, D.C. 20549

                                   Form 8-K

                                CURRENT REPORT

    Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934



         Date of Report (Date of earliest event reported) May 1, 1999


                             DIANON Systems, Inc.
            (Exact name of registrant as specified in its charter)



         Delaware                   000-19392                 06-1128081
- --------------------------------------------------------------------------------
      (State or other            (Commission File            (IRS Employer
       jurisdiction
     of incorporation)               Number)              Identification No.)



200 Watson Boulevard, Stratford, Connecticut                     06615
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(Address of principal executive offices)                        (Zip Code)



Registrant's telephone number, including area code   (203) 381-4000
                                                     --------------




- ------------------------------------------------------------------------------
        (Former name or former address, if changed since last report.)


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Item 2.        Acquisition or Disposition of Assets.

      On May 1, 1999  (the  "Effective  Date"),  pursuant  to an Asset  Purchase
Agreement dated as of April 7, 1999 among DIANON Systems,  Inc. (the "Company"),
Kyto Meridien Diagnostics,  L.L.C.  ("KMD"),  Kyto Diagnostics,  L.P., ("Kyto"),
Meridian  Diagnostics  Labs,  Inc., A. Bruce Shapiro and Ralph M. Richart,  M.D.
(the  "Asset  Purchase  Agreement"),  the Company  acquired  from KMD all of the
assets of KMD (except  certain  excluded  assets)  related to KMD's  business of
owning and operating  laboratories  that provide anatomic,  pathology,  surgical
pathology  and clinical  laboratory  testing  services to patients,  physicians,
hospitals,  clinics,  managed care organizations and other health care providers
(the  "Business").  On the  Effective  Date,  the Company also  assumed  certain
liabilities of KMD under certain equipment leases and other contracts related to
the Business  together with certain employee related  liabilities.  The purchase
price  consisted of (i) cash payments and  transaction  costs of $10,500,000 and
$200,000,  respectively (ii) 300,000 shares of the Company's common voting stock
valued at $2,465,625 (iii) certain  liabilities  assumed and (iv) within 45 days
of the Closing  Date,  an amount  equal to the  Business's  accounts  receivable
balance  (adjusted for non-current  accounts)  existing on the Closing Date. The
amount of the purchase  price was determined  through arms' length  negotiations
between the Company and KMD. The Company  used  working  capital and its line of
credit facility from First Union National Bank to fund the cash component of the
purchase price. The acquisition will be accounted for under the purchase method.

      In  connection  with the  transaction,  the Company  also  entered  into a
registration rights agreement with KMD pursuant to which the Company granted KMD
certain "piggyback" registration rights in respect of the shares of common stock
issued to KMD as part of the Purchase Price.

      The Company has also  entered  into  certain  employment  agreements  with
certain  employees of KMD. These agreements are attached hereto and incorporated
by reference.

Item 7.        Financial Statements and Exhibits.

(a)   Financial statements of businesses acquired.

   Included as an exhibit are the audited  financial  statements  of KMD for the
year ended December 31, 1998.

(b) Pro forma financial information.

   The following pro forma financial statements give effect for the purchase and
are  presented  for  illustrative  purposes  only.  These  pro  forma  financial
statements are not necessarily indicative of the operating results and financial
position  that might  have been  achieved  had the  purchase  occurred  as of an
earlier  date,  nor are they  necessarily  indicative  of operating  results and
financial position which may occur in the future.

   A pro forma  condensed  balance  sheet is provided  as of  December  31, 1998
giving effect to the purchase as though it had been  consummated on that date. A
pro forma  condensed  statement

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of operations is provided for the year ended  December 31, 1998 giving effect to
the purchase as though it had occurred at the beginning of the year.

   The historical  condensed statement of operations for the year ended December
31, 1998 is derived from the  historical  consolidated  financial  statements of
DIANON  Systems,  Inc.  and should be read in  conjunction  with the 1998 Annual
Report on Form 10-K.



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                               DIANON Systems, Inc.
                         Pro Forma Condensed Balance Sheet
                                 December 31, 1998


                                                           Pro Forma (unaudited)
                                                         ---------------------------
                                         Historical      Acquisition
                                          Actual          of KMD          Adjusted
                                          ------          ------          --------
      ASSETS

CURRENT ASSETS
                                                               
     Cash and cash equivalents          $12,126,076     $(4,700,00(a)   $
                                                                          7,426,076
     Accounts receivable, net of         14,403,878                      14,403,878
       allowances
     Other current assets                 3,036,342        123,000(a)     3,159,342
                                         ----------      ----------      -----------
            Total current assets         29,566,296     (4,577,000)      24,989,296

PROPERTY AND EQUIPMENT, net               5,534,485        400,000(a)     5,934,485

INTANGIBLE ASSETS,  net of                  377,751     12,972,625(a)    13,350,376
accumulated amortization

OTHER NONCURRENT ASSETS                   1,224,583                       1,224,583
                                         ==========      ==========      ===========
            TOTAL ASSETS                $36,703,115     $8,795,625      $45,498,740
                                         ==========      ==========      ===========



      LIABILITIES AND STOCKHOLDERS' 
      EQUITY

BANK LOANS                                   -           $6,000,000(a)   $6,000,000
OTHER CURRENT LIABILITIES               $5,239,376          330,000(b)    5,569,376
                                         ----------      ----------      -----------
            Total current liabilities    5,239,376       6,330,000       11,569,376

LONG-TERM PORTION OF CAPITALIZED            80,675                           80,675
   LEASE OBLIGATIONS
                                         ----------      ----------      -----------
            Total liabilities            5,320,051       6,330,000       11,650,051
                                         ----------      ----------      -----------

STOCKHOLDERS' EQUITY
     Common stock, par value $.01           68,088             780 (a)       68,868
     Additional paid-in capital         27,398,120         683,991 (a)   28,082,111
     Retained earnings                   5,697,710                        5,697,710
     Common stock held in treasury, at  (1,780,854)     1,780,854 (a)       -
       cost                              ----------      ----------      -----------
            Total stockholders' equity   31,383,064      2,465,625       33,848,689
                                         ----------      ----------      -----------

TOTAL  LIABILITIES  AND   STOCKHOLDERS' $36,703,115     $8,795,625      $45,498,740
  EQUITY                                 ==========      ==========      ===========

See  accompanying  notes  to  pro  forma financial statements





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                              DIANON Systems, Inc.
                   Pro Forma Condensed Statement of Operations
                                December 31, 1998


                                                               Pro Forma (unaudited)
                                                      ----------------------------------------
                                          Historical  Acquisition
                                           Actual       of KMD      Adjustments  Adjusted
                                           ------       ------      -----------  --------

                                                                            
NET REVENUES                             $62,181,503 $14,631,433                $76,812,936
COST OF SALES                             35,670,153   7,035,159                 42,705,312
                                          ----------  -----------   ----------   ----------

      GROSS PROFIT                        26,511,350   7,596,274                 34,107,624

SELLING, GENERAL AND ADMINISTRATIVE       21,464,737   6,318,288     $783,754 (c)28,566,779
EXPENSES
RESEARCH AND DEVELOPMENT EXPENSES           528,478       -             -          528,478
                                          ----------  -----------   ----------   ----------

      INCOME FROM OPERATIONS              4,518,135    1,277,986    (783,754) (c)5,012,367
INTEREST INCOME, NET                        682,138        5,330    (595,000) (c)   92,468
                                          ----------  -----------   ----------   ----------

    INCOME  BEFORE  PROVISION  FOR INCOME 5,200,273    1,283,316    (1,378,754)  5,104,835
     TAXES 
PROVISION FOR INCOME TAXES                2,245,943       -          (41,038) (c)2,204,905
                                          ----------  -----------   ----------   ----------

      NET INCOME                          $2,954,330  $1,283,316    $(1,337,716) $2,899,930
                                          ==========  ===========   ==========   ==========


      EARNINGS PER SHARE
         BASIC                                $0.44                                  $0.42
         DILUTED                              $0.43                                  $0.40

      WEIGHTED AVERAGE SHARES OUTSTANDING
         BASIC                            6,677,524      300,000                 6,977,524
         DILUTED                          6,902,080      300,000                 7,202,080


See  accompanying   notes  to  pro  forma financial statements







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DIANON SYSTEMS, INC.
NOTES TO PRO FORMA FINANCIAL STATEMENTS (UNAUDITED)

Note 1.        BASIS OF PRESENTATION

      The pro forma financial statements are presented for illustrative purposes
only,  giving  effect  for the  purchase  of the  operations  of  Kyto  Meridien
Diagnostics, L.L.C. (KMD).

      The pro forma condensed balance sheet as of December 31, 1998 includes the
impact of all transactions,  whether of a recurring or nonrecurring nature, that
can be reasonably estimated and should be reflected as of that date.

Note 2.        PRO FORMA ADJUSTMENTS

      Pro forma adjustments include amounts as follows:

     (a)  The purchase of  inventory,  prepaid  expenses,  plant and  equipment,
          customer lists and other intangible assets through the payment of cash
          portion of purchase  price and  issuance  of 300,000  shares of common
          stock,  222,019 of which were from treasury stock. The cash portion of
          the purchase price,  exclusive of transaction  costs of $200,000,  was
          financed  through the draw down of $6,000,000  from the company's line
          of credit and the use of $4,500,000 of the company's cash.

     (b)  Accrual of employee related benefit costs.

     (c)  Amortization  of  intangible  assets,  loss  of  interest  income  and
          interest expense on acquisition  debt, all net of related tax effects.
          Includes a provision  for income taxes for acquired  company which had
          been  organized  as a  partnership  and as such,  did not  reflect any
          provision for income taxes in its financial statements.

   The  pro  forma   financial   statements   do  not  reflect  any  savings  or
efficiencies, if any, which will arise upon the integration of KMD's general and
administrative functions into DIANON.

(c)   Exhibits.

      10.1  Asset  Purchase  Agreement  dated as of April 7, 1999  among  DIANON
Systems,  Inc.,  Kyto Meridien  Diagnostics,  L.L.C.,  Kyto  Diagnostics,  L.P.,
Meridian Diagnostics Labs, Inc., A. Bruce Shapiro and Ralph M. Richart, M.D.

      10.2 Registration  Rights Agreement dated as of May 1, 1999 between DIANON
Systems, Inc. and Kyto Meridien Diagnostics, L.L.C.

      10.3 Consulting Agreement dated May 1, 1999 by and between DIANON Systems,
Inc. and A. Bruce Shapiro

      10.4 Employment Agreement dated May 1, 1999 by and between DIANON Systems,
Inc. and Ralph M. Richart, M.D.


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      10.5 Employment Agreement dated May 1, 1999 by and between DIANON Systems,
Inc. and Beth Phillips

      10.6 Employment Agreement dated May 1, 1999 by and between DIANON Systems,
Inc. and Dana Shapiro

      23 Auditors consent

      99.1 Press Release

      99.2 KMD financial statements for the year ending December 31, 1998


                                  Signatures



Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

                                    DIANON Systems, Inc.


May 4, 1999                         /s/ DAVID R. SCHREIBER
- ------------------                  -------------------------------------------
      Date                          David R. Schreiber
                                    Senior Vice President, Finance and 
                                    Chief Financial Officer
                                    (Principal Financial and Accounting Officer)




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