Anemia

Anemia is when you have a lack of red blood cells or hemoglobin. A patient can be diagnosed with anemia based on their CBC. We would look specifically at the hematocrit (concentration of red blood cells and concentration of hemoglobin).

We cannot depend on O2 saturation (SpO2) because that reading could still be high in an anemic patient. SpO2 is only an indication of how much of the patient's hemoglobin is carrying oxygen. Even though the patient may have less hemoglobin, the hemoglobin can still be working at full capacity. A low SpO2 (lower than 90%) is called hypoxemia.

Thanks to Jose!