Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Casdin Eli 2. Issuer Name and Ticker or Trading Symbol STANDARD BIOTOOLS INC. [LAB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O STANDARD BIOTOOLS INC., 50 MILK STREET, 10TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 02/26/2026 (Street) BOSTON, MA 02109 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 02/26/2026 A 52,991(1) A $1.17 2,954,053(2) D Common Stock 13,939,637 I Casdin Private Growth Equity Fund II, L.P.(3) Common Stock 2,744,219 I By Casdin Private Growth Equity Fund, L.P.(4) Common Stock 72,100,000 I Casdin Partners Master Fund, L.P.(5)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Casdin Eli C/O STANDARD BIOTOOLS INC. 50 MILK STREET, 10TH FLOOR BOSTON, MA 02109	X	X

Signatures

/s/ Eli Casdin		03/02/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Represents Restricted Stock Units ("RSUs") that vest as to 25% on the last day of the last month of each fiscal quarter of 2026, subject to the Reporting Person's continued service through the applicable vesting date.
(2)	The RSUs were issued to the Reporting Person, who elected to take RSUs in lieu of $62,000 in cash compensation for services as a board member.
(3)	The securities are owned directly by Casdin Private Growth Equity Fund II, L.P. (the "Equity Fund II") and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC ("Casdin"), the investment adviser to the Equity Fund II, and (ii) Eli Casdin, the managing member of Casdin.
(4)	The securities are owned directly by Casdin Private Growth Equity Fund, L.P. (the "Equity Fund") and may be deemed to be indirectly beneficially owned by (i) Casdin, the investment adviser to the Equity Fund, and (ii) Eli Casdin, the managing member of Casdin.
(5)	The securities are owned directly by Casdin Partners Master Fund, L.P. (the "Master Fund") and may be deemed to be indirectly beneficially owned by (i) Casdin, the investment adviser to the Master Fund, (ii) Casdin Partners GP, LLC, the general partner of the Master Fund (the "GP"), and (iii) Eli Casdin, the managing member of Casdin and the GP.
Remarks: The Reporting Person disclaims beneficial ownership in the securities reported on this Form 4 except to the extent of his pecuniary interest, if any, therein, and this report shall not be deemed to be an admission that the Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

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