Study Of Non-invasive Measurement Of Human Hemoglobin Concentration By Near Infrared Spectroscopy

The hemoglobin concentration is a key factor to estimate people's anemiaprobability and iron situation. An easy efficacious testing method is necessary toevaluate people's health. However most present measurement methods need bloodfrom patients that are not only troublesome but also expensive, and the pain of bloodsampling makes it impossible for most people that testing their hemoglobin levelsanytime. Near infrared spectroscopy (NIRS) technology has been used widely for itsobvious advantages such as high speed, low cost, non-invasiveness and environmentprotection. Measuring human hemoglobin concentration with NIRS is a newapplication of NIRS in clinical field.Different Chinese people's anemia situation were investigated, and it wassummarized that the development of testing hemoglobin concentration non-invasivelywith NIRS in the world. The second joint of forefinger was chosen as the testing site.The signal-to-noise and the stability of HR2000 spectrometer were estimated.When the spectrometer is warmed-up enough, CV of transmission is 2‰-6‰, thestability is 1%, and CV of reflection is 6‰-8‰;the SNR of testing forefinger is 5‰-1%, the stability of testing the same person in one day is 4%, and 5% for the sameperson in different days.The model of hemoglobin solution was excellent, RMSEP=40.06mg/dL,R=0.998.Based on the modified Lambert-Beer principle, the absolute concentration ofHbO₂ and Hb can be estimated. The relation between PDPF and tissue thickness wasalso simulated with Monte Carlo method.When measuring the diffuse reflection spectrum of forefinger, the hemoglobinconcentration calculated from two certain wavelengths (760nm, 850nm) is better thanthat predicted with the model. The relative error of all male volunteers is below 7.39%,and R is 0.954, and for all female volunteers, the relative error below 7.26%, R 0.969.