This paper discusses the design, fabrication, and use of thermoplastic polyurethane optical fibers intended for oxygen saturation measurements. It includes an evaluation of the fiber attenuation and the creation of two probes for the measurement assessment. For comparison, a third probe is made using conventional glass optical fibers. The assessment is conducted in two stages: first, absorption measurements are performed using a mixture of methylene blue and intralipid diluted in deionized water
second, a measurement with human blood is conducted to demonstrate the effectiveness of such fibers in measuring blood oxygen saturation. Additionally, a comprehensive study of measurement stability is provided.