SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* CRANDELL KEITH (Last) (First) (Middle) 8755 WEST HIGGINS ROAD, SUITE 1025 (Street) CHICAGO IL 60631 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Quanterix Corp [ QTRX ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 01/02/2019
	4. If Amendment, Date of 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

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	01/02/2019		A		2,270(1)	A	$0.00	4,540(2)	D
Common Stock								2,412,001	I	Held by ARCH Venture Fund VI, L.P.(3)
Common Stock								1,537,684	I	Held by ARCH Venture Fund VIII Overage, L.P.(4)

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 Securities Underlying Derivative Security (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: 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
Stock Option (Right to Buy)	$18.24	01/02/2019		A		7,900(5)		12/31/2019	01/02/2029	Common Stock	7,900	$0.00	7,900	D

Explanation of Responses:

1. Represents restricted stock units that vest as to 100% of the shares on December 31, 2019 granted pursuant to the Quanterix Corporation 2018 Non-Employee Director Compensation Policy. Each restricted stock unit represents the right to receive one share of the Issuer's common stock.

2. Includes 2,270 restricted stock units.

3. The shares are held of record by ARCH Venture Fund VI, L.P. ("ARCH Fund VI"). The sole general partner of ARCH Fund VI is ARCH Venture Partners VI, L.P. ("ARCH Partners VI"), which may be deemed to beneficially own the shares held by ARCH Fund VI. The sole general partner of ARCH Partners VI is ARCH Venture Partners VI, LLC ("ARCH VI LLC"), which may be deemed to beneficially own the shares held by ARCH Fund VI. ARCH Partners VI and ARCH VI LLC disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. As a managing director of ARCH VI LLC, the Reporting Person may be deemed to beneficially own the shares held by ARCH Fund VI. The Reporting Person disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein.

4. The shares are held of record by ARCH Venture Fund VIII Overage, L.P. ("ARCH Fund Overage"). The sole general partner of ARCH Fund Overage is ARCH Venture Partners VIII, LLC ("ARCH VIII LLC"), which may be deemed to beneficially own the shares held by ARCH Fund Overage. ARCH VIII LLC disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein. As a managing director of ARCH VIII LLC, the Reporting Person may be deemed to beneficially own the shares held by ARCH Fund Overage. The Reporting Person disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein.

5. Represents non-qualified stock option to purchase 7,900 shares of common stock granted pursuant to the Quanterix Corporation 2018 Non-Employee Director Compensation Policy.

Remarks:

	/s/ Brian Keane, as Attorney-in-Fact for Keith L. Crandell	01/04/2019
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
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