A sample receiving assembly, comprising: a support member having a bore extending therethrough; an arm holder pivotally connected to the support member; an arm disposed within the arm holder and axially slidable relative thereto, the arm comprising a distal end; a sample probe partially disposed within the arm, the sample probe having a first portion extendable through the distal end (away from the bore) of the arm and a second portion extending through the bore of the support member; and wherein the arm holder, the arm, and the sample probe are rotatable to selected positions and the arm is axially movable relative to the arm holder and the sample probe in a way that the arm is selectively positionable to alter the position of the distal end of the sample probe relative to the arm so that the probe can receive a sample from different types of sample transport containers, wherein the arm holder includes a hollow pivot pin received by the support member bore, and wherein the sample probe second portion extends axially through the hollow pivot pin, the sample receiving assembly further comprising: a guide pin disposed on the arm; characterized in that the sample receiving assembly comprises a plurality of linear grooves formed along the support surface, the plurality of linear grooves sized to receive the guide pin and positioned to guide retraction of the arm into the arm holder from an extended position to a retracted position, and a curved groove in the support surface, the curved groove sized to receive the guide pin and positioned to guide the guide pin to the plurality of linear grooves upon rotation of the arm and arm holder, the plurality of linear grooves within the support member comprising: a first linear groove extending vertically from the curved groove toward the bore; a second linear groove extending from the curved groove and away from the bore at a first angle from the first linear groove; a third linear groove extending from the curved groove and away from the bore at a second angle from the first linear groove; and a fourth linear groove extending from the curved groove and away from the bore at a third angle from the first linear groove. a support member having a bore extending therethrough; an arm holder pivotally connected to the support member; an arm disposed within the arm holder and axially slidable relative thereto, the arm comprising a distal end; a sample probe partially disposed within the arm, the sample probe having a first portion extendable through the distal end (away from the bore) of the arm and a second portion extending through the bore of the support member; and a guide pin disposed on the arm; characterized in that the sample receiving assembly comprises a plurality of linear grooves formed along the support surface, the plurality of linear grooves sized to receive the guide pin and positioned to guide retraction of the arm into the arm holder from an extended position to a retracted position, and a curved groove in the support surface, the curved groove sized to receive the guide pin and positioned to guide the guide pin to the plurality of linear grooves upon rotation of the arm and arm holder, the plurality of linear grooves within the support member comprising: a first linear groove extending vertically from the curved groove toward the bore; a second linear groove extending from the curved groove and away from the bore at a first angle from the first linear groove; a third linear groove extending from the curved groove and away from the bore at a second angle from the first linear groove; and a fourth linear groove extending from the curved groove and away from the bore at a third angle from the first linear groove. a first linear groove extending vertically from the curved groove toward the bore; a second linear groove extending from the curved groove and away from the bore at a first angle from the first linear groove; a third linear groove extending from the curved groove and away from the bore at a second angle from the first linear groove; and a fourth linear groove extending from the curved groove and away from the bore at a third angle from the first linear groove.