Optical transmission sample holder and analysis, particularly for hemoglobin

A device for analyzing a sample, comprising:

• a first plate, a second plate, a plurality of light-guiding spacers (LGS's), a sampling region, and a reference region, wherein:
• (i) the first plate and the second plate are movable relative to each other into a closed configuration, wherein, in the closed configuration, the first plate and second plate are operable to compress at least part of the sample into a layer having a thickness, wherein the layer is confined by the sample contact areas of the first and second plates, and the thickness of the layer is regulated by the first and second plates and the light-guiding spacers;
• and
• (ii) in the closed configuration, the plurality of light-guiding spacers is sandwiched between the first and second plates to form the sampling region and the reference region, and each end of each light-guiding spacer (LGS) in direct contact with one of the plates forming a LGS-plate contact area and is configured to allow a light to transmit from the first plate, through the LGS, to the second plate without going through a sample;
• (iii) the sampling region is a region where the light can go through, in sequence, the first plate, the sample, and the second plate, wherein the sampling region does not have the LGS's;
• and
• (iv) the reference region is a region where the light transmits through, in sequence, the first plate, the light-guiding spacers, and the second plate, without going through the sample;
• wherein the LGS-plate contact areas and a lateral cross-section of the LGS's are larger than the wavelength of the light.