This statistic comes from a survey conducted by the Bureau of Justice Statistics (BJS), a division of the U.S. Department of Justice, which found that on June 30, 2009, the United States housed 203,233 Federal prisoners, 1,326,547 State prisoners, and 767,620 detainees in local jails.
Doctors try to determine if a low red blood cell count is caused by increased blood loss of red blood cells or from decreased production of them in the bone marrow. Knowing whether the number of white blood cells and/or platelets has changed also helps determine the cause of anemia.
Lead poisoning results in low red blood cell count because lead weakens the membranes of the red blood cells and creates radicals that interfere with DNA. Sickle cell anemia causes deformed red blood cells that can't carry oxygen the way they should, according to Mayo Clinic. These cells clog blood vessels and can block the flow of blood.