Application of near infrared spectroscopy to the determination of haemoglobin

Seventy-two whole blood samples were investigated to determine the relationship between their spectral data measured in the near infrared (NIR) wavelength region and haemoglobin content based on laboratory data determined by a routine standard method as reference. Blood samples were obtained from the 1st Department of Medicine, Imre Haynal University of Health Sciences. Donors were selected randomly without respect to age, sex, state of health or medical treatment, from apparently healthy volunteers as well as from ambulatory and hospitalized patients. NIR spectra were measured with a SPECTRALYZER 1025 (PMC) computerized spectrophotometer in the 1000–2500 nm wavelength region. The relationship between laboratory data and values of the second derivative (i.e. second order finite difference) of the log(1/TF) spectra measured at different wavelengths was determined by multiple linear regression (MLR) using three- and four-term linear summation equations. The cross-validated standard error of performance (SEP) for haemoglobin was 1.348 g dL−1 with a three term model and 1.251 g dL−1 with a four term model over the range from 5.9 to 20 g dL−1. This preliminary study indicates that NIR measurements can be directly related to haemoglobin content and can be used to determine haemoglobin content in human whole blood.