A system for measuring the level of at least one analyte of a subject, the system comprising: a probe device for attaching to the subject, said probe device carrying an optical assembly (17s, 17g) configured and operable for applying optical measurements to a measurement location in the subject and generating optical measured data indicative thereof, the optical measurements comprising measurements taken from the measurement location in at least one of pulsatile and occlusive blood states; an auxiliary system comprising: a pressure system having a pressure source configured and operable for controllably supplying fluid pressure communicated to said probe device for applying pressure to the subject in the vicinity of the measurement location and affecting at least one of said pulsatile and occlusive blood states at the measurement location, and a pressure sensor system having a pressure sensor for measuring changes of said fluid pressure inside the pressure system during the application of said optical measurements and the application of said pressure to the subject in the vicinity of the measurement location and generating pressure data, said pressure data being indicative of the fluid pressure changes inside the pressure system caused by vascular volumetric changes in the measurement location to which said pressure is being applied while said optical measurements are conducted; and a control system configured and operable for receiving and processing the pressure data and the optical measured data, determining at least one ratio between the optical measured data and the corresponding pressure data, and determining the at least one analyte of the subject based on said at least one ratio between the optical measured data and the corresponding pressure data. a probe device for attaching to the subject, said probe device carrying an optical assembly (17s, 17g) configured and operable for applying optical measurements to a measurement location in the subject and generating optical measured data indicative thereof, the optical measurements comprising measurements taken from the measurement location in at least one of pulsatile and occlusive blood states; an auxiliary system comprising: a pressure system having a pressure source configured and operable for controllably supplying fluid pressure communicated to said probe device for applying pressure to the subject in the vicinity of the measurement location and affecting at least one of said pulsatile and occlusive blood states at the measurement location, and a pressure sensor system having a pressure sensor for measuring changes of said fluid pressure inside the pressure system during the application of said optical measurements and the application of said pressure to the subject in the vicinity of the measurement location and generating pressure data, said pressure data being indicative of the fluid pressure changes inside the pressure system caused by vascular volumetric changes in the measurement location to which said pressure is being applied while said optical measurements are conducted; and a control system configured and operable for receiving and processing the pressure data and the optical measured data, determining at least one ratio between the optical measured data and the corresponding pressure data, and determining the at least one analyte of the subject based on said at least one ratio between the optical measured data and the corresponding pressure data.