Hemoglobin assay in anemic patients with a photothermal spectral-domain optical coherence reflectometric sensor

We recently introduced an optical sensor, termed photothermal spectral-domain optical coherence reflectometer (PT SD-OCR), capable of direct measurement of hemoglobin concentration ([Hb]) without chemicals and pre-processing of blood. PT SD-OCR measures [Hb] by quantifying refractive index changes of blood samples due to photothermal effect under the irradiation of 532-nm light. We evaluated diagnostic accuracy and precision of PT SD-OCR in anemic patients.

We used PT SD-OCR to measure [Hb] in 50 anemic patients, and examined its accuracy against a hematology analyzer (ADVIA 2120i, Siemens AG). Its precision was assessed by examining the SD and CV based on 20 repeated measurements on 3 blood samples. Its performance was also compared with a hemoglobinometer (HemoCue 201+, HemoCue).

The PT SD-OCR demonstrated good correspondence with the hematology analyzer with a Pearson's correlation coefficient of 0.992 and a bias of -0.055 g/dl. Standard deviation and CV were measured to be <0.25 g/dl and <2.05%.

Simple and chemical-free operation of PT SD-OCR enabled rapid and accurate measurement of [Hb] in anemic patients. The sensor is expected to facilitate clinical procedures related to blood-related disorders in patient care.