What Are The Problems Associated With Decreased Haemoglobin Levels?

Do you have any information for the public to read ,paper articles,some resources about a topic of interest. I m looking for anything about problems with low levels of hemoglobin. My sister was hospitalized for 11 days, I think they did every test available to the Doctors. She was discharged with no diagnoses. My email is YYYY@YYYY . My name is Magda Ramia. THANK YOU. I think I think I shoulds try a public library. I M SORRY