Performance of an automated six-wavelength photometer (Radiometer OSM3) for routine measurement of hemoglobin derivatives.

A new instrument for spectrophotometric determination of oxygen saturation (SO2) and the fractions of carboxyhemoglobin (FHbCO) and methemoglobin (FHi), the Hemoximeter OSM3 (Radiometer), was tested by comparative measurements with a multiwavelength method. We found that it gave reliable results for freshly drawn samples from patients. When samples with artificially induced high proportions of HbCO or Hi, or both, were introduced, results were still sufficiently accurate. The presence of sulfhemoglobin (SHb) seriously interfered with the measurement of SO2, FHbCO, and FHi, but the instrument reliably indicated its presence. Because SHb is rarely encountered, a reliable warning for its presence is adequate for clinical practice. Using the instrument in its fetal mode, we obtained accurate results for blood samples from newborns.