The device (1) for optical measurement, particularly for extracorporeal blood circuits, comprises a tubular element (2) having a first end connector (3) and a second end connector (4) connectable, respectively, to a first tube (5) and to a second tube (6) for subjecting a work fluid through the tubular element itself, and an intermediate portion (7) extending between the first end connector (3) and the second end connector (4) and suitable for subjecting the fluid to a non-invasive measurement of one or more parameters, where the tubular element (2) comprises two pieces distinct to one another, of which a first tubular portion (2a) and a second portion (2b) bearing a protruding element (8) suitable to be inserted into a corresponding mating recess provided on a medical apparatus for activating the optical measurement, where the second portion (2b) is suitable to cooperate with the first tubular portion (2a) for fixing the position of the protruding element (8) with respect to the first tubular portion itself,wherein the first tubular portion (2a) defines both the first and second end connectors (3, 4) and the second portion (2b) is movable with respect to the first tubular portion itself and is applied over both the first tubular portion (2a) and the second tube (6) fitted on it； or wherein the first tubular portion (2a) is of the rigid type and the protruding element (8) is realized with soft material.一種用於光學測量的裝置(1)，特別用於體外血液循環，包含：一管狀元件(2)，其係具有一第一端連接器(3)以及一第二端連接器(4)，可個別地連接至一第一管(5)以及一第二管(6)，用於使一工作流體經過該管狀元件本身，以及一中間部分(7)，其係在該第一端連接器(3)與該第二端連接器(4)之間延伸，且適合於對該流體進行一個或多個參數的非侵入式測量，其中該管狀元件(2)包含彼此不同的二個構件，其係為一第一管狀部分(2a)以及一第二部分(2b)，該第二部分(2b)帶有一突出元件(8)，其係適於插入設置在一醫療裝置上之一對應的配合凹部，以啟動該光學測量，其中該第二部分(2b)係適於與該第一管狀部分(2a)共同運作，以相對於該第一管狀部分本身，固定該突出元件(8)的位置，其中該第一管狀部分(2a)定義該第一及第二端連接器(3、4)，以及該第二部分可相對於該第一管狀部分本身移動，且係應用於該第一管狀部分(2a)以及安裝於其上之第二管(6)之上；或者其中該第一管狀部分(2a)係為剛性類型，且該突出元件(8)係以軟性材料實現。
