X0206 3 2017-12-06 0 0001503274 Quanterix Corp QTRX 0001216068 DEKKERS MARIJN E C/O QUANTERIX CORPORATION, 113 HARTWELL AVENUE LEXINGTON MA 02421 1 0 0 0 Series D-1 Preferred Stock Common Stock 77378 D Stock Option (right to buy) 8.16 2027-03-31 Common Stock 31113 D These shares are convertible into the Issuer's common stock in accordance with the Issuer's Restated Certificate of Incorporation, as amended, at any time after the issuance of such shares, at the holder's election. Not applicable. The shares of preferred stock will convert into common stock immediately prior to the closing of the Issuer's initial public offering using a calculation defined in the Issuer's Restated Certificate of Incorporation, as amended, based on the initial purchase price and the conversion rate in effect at the time of conversion. The shares of preferred stock will convert on a 1-for-3.214 basis and such conversion rate is reflected in the amount of common stock underlying the security. The option vests as to 25% of the shares on March 13, 2018 and vests as to an additional 2.083% of the shares per month thereafter until February 28, 2021. Reflects the 1-for-3.214 reverse stock split of the Issuer's common stock effected on December 4, 2017 in connection with the Issuer's initial public offering, pursuant to which (i) the number of shares of common stock underlying the option was divided by 3.214 and (ii) the exercise price of the option was multiplied by 3.214. Exhibit 24.1 - Power of Attorney /s/ Brian Keane, Attorney-in-fact 2017-12-06