CPFT Practice Test 8

A pulse oximeter reads 88% on a patient whose arterial oxygen saturation measured by CO-oximetry is 97%. Which of the following could cause a falsely low SpO₂ reading?

1. Elevated carboxyhemoglobin 2. Dark blue nail polish on the sensor finger 3. Cold fingers with a weak pulse waveform 4. A blood pressure cuff inflating on the same arm