Simultaneous determination of hemoglobin derivatives, oxygen content, oxygen capacity, and oxygen saturation in 10 microliters of whole blood

We describe a new method for simultaneous determination of four hemoglobin derivatives (deoxyhemoglobin, Hb; oxyhemoglobin, HbO2; methemoglobin, Hb+; and carbon monoxide hemoglobin, HbCO) and total oxygen content in 10 microliters of whole blood. Percentage HbO2, HbCO, Hb+, total hemoglobin (Hbt), and oxygen capacity can also be obtained from the experimental data by simple calculations. Total analysis time is 1 min. Blood is diluted 100-fold with a buffer contained in a quasi-anaerobic cuvette, where simultaneous measurements of oxygen pressure (by a po2 electrode) and adsorbance (at 497, 565, and 620 nm) are made. The decrease of oxygen pressure, as recorded by the oxygen electrode, is proportional to the amount of deoxyhemoglobin. The concentrations of HbO2, HbCO, and Hb+ can be obtained from absorbance measurements at the specified wavelengths. The new method eliminates the use of short-path optical cells and, due to the low sample volume requirement, makes possible the automated measurement of hemoglobin derivatives and oxygen saturation in arterialized capillary blood.