What is normal levels of oxygen in the blood? what is considered low and what is considered dangerous? is levels in the 80s ok?

Upper 90-ties: Levels in the 80-es are not ok, we prescribe supplemental oxygen usually for levels below 86-88%. Bear in mind that levels at rest are higher and they will drop with exertion and/or sleep. Also if you retain carbon dioxide (copd, sleep apnea), you should not get too much oxygen. Bottom line, see a doctor!

It is low: If you are asking about oxygen saturation the level should be above 90%. Normally it it is 97 - 99%. If the levels are in the low 80s - the person should be on oxygen. The oxygen saturation is obtained via external device placed on the finger or earlobe. If you obtain arterial blood and measure oxygen level - po2 the level in 80 is ok.

Oxygen level....: The oxygen saturation, or pulse oximetry, should be in the 90's normally. Any value of less than 88% on room air qualifies a patient for supplemental oxygen therapy. So, an oxygen saturation in the 80s is not normal. Your doctor will need to find out why your oxygen level is low and provide treatment.