Optical sensor for detection of free hemoglobin in a whole blood sample

A porous mirror for use in the optical detection of free hemoglobin in a whole blood sample, the porous mirror comprising:

• a translucent slab with a front side and a back side facing away from the front side, wherein the front side is adapted for being contacted with a whole blood sample;
• and
• a reflective layer applied to the front side of the translucent slab, the reflective layer being adapted to reflect light reaching the reflective layer from the translucent slab;
• wherein the translucent slab is provided with dead-end pores extending from respective openings at the front side into the translucent slab, wherein a cross-sectional dimension of the openings of the pores is dimensioned so as to prevent red blood cells from entering the pores, while allowing free hemoglobin to enter the pores.

A sensor for the optical detection of a substance in the plasma fraction of a whole blood sample, the sensor comprising:

• a translucent article comprising (a) at least one membrane comprising pores and (b) a transparent element with a front side and a back side facing away from the front side, wherein the front side is adapted for being contacted with a whole blood sample;
• a reflective layer at the front side of the translucent article, the reflective layer being adapted to reflect light reaching the reflective layer from the translucent article;
• and
• a light source and a detector configured for optically probing the translucent article, wherein the light source is adapted to illuminate at least the pores in the translucent article, wherein the detector is arranged to receive light emerging from the pores in response to an illumination by the light source, and wherein the detector is adapted to generate a signal representative of the detected light;
• wherein the pores in the translucent article are dead-end pores extending from respective openings at the front side, through the reflective layer into the at least one membrane, wherein the pores are only in fluid communication with the sample at the front side of the at least one membrane, wherein a cross-sectional dimension of the openings of the pores is dimensioned so as to prevent red blood cells from entering the pores, while allowing the substance in the plasma fraction of the whole blood sample to enter the pores.