A blood analyzing device comprising: a holder arranged for carrying a container having a cuvette comprising a blood sample; inducing means for inducing movement of blood cells in said blood sample when said container is positioned in said holder; a light source arranged for providing input light into said blood sample; a detector arranged for i) hemoglobin measurements by detecting, at least once within a measuring time interval following positioning of said container in said holder, output light having passed through said blood sample, ii) detecting a change in said induced movement of said blood cells in said blood sample based on said output light from said blood sample after said hemoglobin measurement and iii) generating a detection signal based on said detected change in said induced movement; and a processor connected to said detector and arranged for determining a viscosity representing value representative of a viscosity change in said blood sample based on said detection signal, characterized in that said light source is arranged for providing input light of a wavelength at which a hemoglobin species has maximum absorbance; said detector is arranged for detecting said change in said induced movement of said blood cells in said blood sample as a reduction in a rate of change of absorbance at said wavelength at which said hemoglobin species has maximum absorbance; said processor is arranged for determining at least one of total hemoglobin concentration or concentration of at least one hemoglobin fraction in said blood sample based on said output light detected during said measuring time interval; and said processor is arranged for determining said viscosity representing value based on said detection signal and said at least one of total hemoglobin concentration or concentration of at least one hemoglobin fraction. a holder arranged for carrying a container having a cuvette comprising a blood sample; inducing means for inducing movement of blood cells in said blood sample when said container is positioned in said holder; a light source arranged for providing input light into said blood sample; a detector arranged for i) hemoglobin measurements by detecting, at least once within a measuring time interval following positioning of said container in said holder, output light having passed through said blood sample, ii) detecting a change in said induced movement of said blood cells in said blood sample based on said output light from said blood sample after said hemoglobin measurement and iii) generating a detection signal based on said detected change in said induced movement; and a processor connected to said detector and arranged for determining a viscosity representing value representative of a viscosity change in said blood sample based on said detection signal, characterized in that said light source is arranged for providing input light of a wavelength at which a hemoglobin species has maximum absorbance; said detector is arranged for detecting said change in said induced movement of said blood cells in said blood sample as a reduction in a rate of change of absorbance at said wavelength at which said hemoglobin species has maximum absorbance; said processor is arranged for determining at least one of total hemoglobin concentration or concentration of at least one hemoglobin fraction in said blood sample based on said output light detected during said measuring time interval; and said processor is arranged for determining said viscosity representing value based on said detection signal and said at least one of total hemoglobin concentration or concentration of at least one hemoglobin fraction.