The present invention relates to a device and method for noninvasively determining the hematocrit value of a subject. The device comprises a light source (22, 23) for emitting light onto a skin area of the subject, said light comprising first light at a first wavelength in a first wavelength range between 500 and 1000 nm and second light at a second wavelength in a second wavelength range between 1000 and 2000 nm, a reflection detector (24) for detecting light reflected from said skin area of the subject in response to light illumination by said light source, a transmission detector (25) for detecting light transmitted through said skin area of the subject in response to light illumination by said light source, a processing unit (31) for deriving plethysmography, PPG, signals for said first and second wavelengths from the light detected by said reflection detector (24) and said transmission detector (25), and an analysis unit (32) for determining the hematocrit value of the subject from said PPG signals.
