SECURITIES AND EXCHANGE COMMISSION
                           WASHINGTON, D.C. 20549

                       -----------------------------


                                SCHEDULE 13D
                               (Rule 13d-101)

      INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULE
      13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(a)
                             (Amendment No. 1)

                             i-STAT Corporation
- ------------------------------------------------------------------------------
                              (Name of Issuer)

                  Common Stock, par value $0.15 per share
- ------------------------------------------------------------------------------
                       (Title of Class of Securities)

                                 450312103
- ------------------------------------------------------------------------------
                               (CUSIP Number)

                              Jose M. de Lasa
                      Senior Vice President, Secretary
                            and General Counsel
                            Abbott Laboratories
                            100 Abbott Park Road
                      Abbott Park, Illinois 60064-3500
                               (847) 937-6100
- ------------------------------------------------------------------------------
               (Name, Address and Telephone Number of Persons
             Authorized to Receive Notices and Communications)

                             September 2, 1998
- ------------------------------------------------------------------------------
          (Date of Event Which Requires Filing of this Statement)

         If the filing person has previously filed a statement on Schedule
13G to report the acquisition which is the subject of this Schedule 13D,
and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g),
check the following box [ ]


                       (Continued on following pages)
                            (Page 1 of 4 Pages)






CUSIP NO.: 450312103                                    13D
1        NAME OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
                 Abbott Laboratories (# 36-0698440)

2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP             (a) (_)
                                                                      (b) (_)

3        SEC USE ONLY

4        SOURCE OF FUNDS
         WC

5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEM 2(d) or 2(e)                                  (_)

6        CITIZENSHIP OR PLACE OF ORGANIZATION
                   Illinois

                           7        SOLE VOTING POWER
                                    2,000,000 shares of Common Stock
NUMBER OF
SHARES                     8        SHARED VOTING POWER
BENEFICIALLY                        0
OWNED BY
EACH                       9        SOLE DISPOSITIVE POWER
REPORTING                           2,000,000 shares of Common Stock
PERSON
WITH                       10       SHARED DISPOSITIVE POWER
                                    0

11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING
         PERSON
                  2,000,000 shares of Common Stock

12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES                                               (_)

13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           11.5%

14       TYPE OF REPORTING PERSON
                           CO


                                                       Page 2 of 4 Pages





         This Amendment No. 1 (this "Amendment") amends the Schedule 13D
filed by Abbott Laboratories, an Illinois corporation ("Abbott") on August 13,
1998 (the "Original Schedule 13D"). Capitalized terms used but not
otherwise defined in this Amendment shall have the meanings assigned to
those terms in the Original Schedule 13D.

ITEM 3.           SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION

         The aggregate purchase price for the purchase by Abbott described
herein of 2,000,000 shares of the common stock, par value $0.15 per share,
(the "Common Stock") of i-STAT Corporation (the "Issuer") was $22,700,000.
The source of such funds was the working capital of Abbott.

ITEM 4.           PURPOSE OF THE TRANSACTION

         As previously disclosed, pursuant to the Stock Purchase Agreement
dated as of August 3, 1998 between Abbott and the Issuer, Abbott agreed to
purchase 2,000,000 shares of Common Stock at a purchase price of
$22,700,000. On September 2, 1998, Abbott and the Issuer consummated the
transactions contemplated by the Stock Purchase Agreement, including the
purchase by Abbott of 2,000,000 shares of Common Stock. Also on September 2,
1998, the Issuer and Abbott entered into the Registration Rights
Agreement and the closings were held under the Distribution Agreement and
the Research Agreement.

ITEM 5.           INTEREST IN SECURITIES OF THE ISSUER

         (a) Abbott is the beneficial owner of all 2,000,000 shares of
Common Stock. Such Shares represent 11.5% of the total outstanding shares
of Common Stock.

         (b) Abbott has the sole power to vote and to dispose of all 2,000,000
shares of Common Stock.

         (c) Other than the execution of the Stock Purchase Agreement on
August 3, 1998 and the purchase of 2,000,000 shares of Common Stock on
September 2, 1998, Abbott has not effected any transactions in the Common
Stock in the past 60 days.

         (d) - (e)   Not applicable.


                                                         Page 3 of 4 Pages




                                  SIGNATURE

         After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this statement is true,
complete and correct.

Dated: September 2, 1998


                                               ABBOTT LABORATORIES


                                               By: /s/ Miles D. White
                                                   ---------------------
                                               Name: Miles D. White
                                               Title: Executive Vice President



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