Which factors influence the accuracy of pulse oximetry readings?

Updated: May 14, 2020
  • Author: Kevin McCarthy, RPFT; Chief Editor: Nader Kamangar, MD, FACP, FCCP, FCCM  more...
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Overestimation of SaO2 is possible with bright sunlight on the probe, fluorescent lights, operating room lights, infrared heat lamps, elevated CoHb, elevated metHb, anemia, and motion artifact if the actual SaO2 is less than 85%.

Underestimation of SaO2 is possible because intravascular dyes, such as methylene blue and indocyanine green, produce transient reductions in SpO2. Fingernail polish, increased venous pressures, and motion artifact if the actual SaO2 is greater than 85% also can cause underestimation of the SaO2.

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