<prompt> Concerning pulse oximetry true isOxyhemoglobin and deoxyhemoglobin light absorption is equal at the isobestic point of 660nmMeasurements are accurate in the presence of high levels of bilirubinMeasurements are accurate in presence of carboxyhaemoglobinMeasurements are accurate in presence of pigmented skin.  <response>: Light absorption of both oxy and deoxy haemoglobin is equal at isobestic point of 805 nm. Bilirubin, carboxyhemoglobin and methaemoglobin can affect the reading of pulse oximeter. Pigmented skin doesnt influence the reading. 