Bilirubin

There is evidence that bilirubin does not affect the accuracy of pulse oximetry and pulse oximeters are still accurate in the presence of severe hyperbilirubinaemia ¹.

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Anaemia

In theory there is no reason anaemia should cause pulse oximeters to be inaccurate and experiments in dogs have shown accuracy reliable enough for "clinical purposes" (Moyle 2002:49)² as long as the packed cell volume was larger than 15%. Clinical experience has shown good performance with haemoglobin as low as 2.3 g/dl ².

Sickle cell disease

It has been shown that pulse oximetry can detect low oxygen saturation accurately in sickle cell disease ³, however other researchers have suggested caution in interpreting pulse oximetry values in sickle cell disease.