Feasibility assessment of optical non-invasive total hemoglobin measurement

A series of experiments were performed to assess the feasibility of measuring total hemoglobin (Hb(T)) non-invasively. using light in the visible to near infrared (NIR) range. The experiments included spectroscopic measurements of both in vitro isolated tissue components and in vivo human tissue (73 subjects) in a clinical setting. Several different methods of estimating Hb(T), all by optical non-invasive means, were tested and compared for accuracy relative to standard invasive methods. By combining time-resolved optical absorbances at 3 wavelengths, 750, 965, and 1320 nm, in a fashion that is highly analogous to pulse oximetry, Hb(T) was predicted with a standard error of 1.1 g/dL.