Correct and spurious calibration of the Oxicom oximeter

Oxicom oximeters are widely used in cardiac catheterization laboratories. To calibrate the Oxicom oximeter, samples of oxygenated and deoxygenated whole blood are first analyzed on a CO-Oximeter, and then the Oxicom is adjusted to agree with the CO-Oximeter's readings. Subsequently, the Oxicom's calibration is confirmed at frequent intervals by taking readings from a white plastic stick that is inserted into the instrument to simulate a blood sample. The data in this report demonstrate that the readings from the white plastic "test simulator" failed to detect an out-of-calibration condition. By contrast, when the Oxicom was carefully adjusted to agree with a CO-Oximeter's readings on arterial and venous blood, a linear calibration curve resulted, and the Oxicom achieved its specified accuracy (2.5%). The precautions necessary to calibrate the Oxicom correctly are enumerated in the text.