This is an excellent explanation. To provide some context, though, a hemoglobin of 6.6 is not all that low. It’s certainly low enough that the person should get transfused a unit of blood (usually indicated if the value is below 7). However, the real issue is figuring WHY it got low in the first place. Is the patient’s own immune system attacking their blood (autoimmune)? Is there a bleed somewhere (like the gastrointestinal tract)? Is there cancer in the bone marrow leaving (less likely if only the red cells are low but not the other blood counts)? Is there an iron deficiency for some reason? Figuring out the cause of the anemia will be important to knowing how to treat and the actual prognosis.