Optical transmission sample holder and analysis, particularly for hemoglobin

A device for an optical transmission analysis of sample by a light, comprising:

• a first plate, a second plate, and a light-guiding spacer (LGS), wherein:
• the first plate and the second plate are movable relative to each other to form different configurations, including an open configuration and a closed configuration;
• in the closed configuration, the first and second plates are configured to compress a sample into a layer between the first and second plates, and each of the first and second plates has a sample contact area contacting the sample;
• in the closed configuration, the light-guiding spacer is sandwiched between the first and second plates and in direct contact with the first and second plates to form a sample region and a reference region;
• wherein the sample region is a region where the light is capable of transmitting through the first plate, the sample, and the second plate, wherein the sample region does not have the LGS;
• and
• the reference region is a region where the light is capable of transmitting through the first plate, the light-guiding spacer, and the second plate, without going through the sample;
• and
• wherein the lateral cross-section of the LGS is larger than a wavelength of the light.