Patient presents with symptoms suggestive of low ferritin, including fatigue, weakness, pallor, shortness of breath, dizziness, and brittle nails.  Review of systems reveals complaints of headaches, cold intolerance, and restless leg syndrome.  Patient history includes heavy menstrual bleeding in premenopausal females, gastrointestinal bleeding (possible peptic ulcer disease, colon cancer to be ruled out), dietary insufficiency (vegetarianism, veganism),  and malabsorption syndromes (celiac disease, Crohn's disease).  Physical examination reveals pale conjunctiva and koilonychia.  Laboratory results show a serum ferritin level below the normal range, indicating iron deficiency.  Iron panel reveals low serum iron, elevated total iron binding capacity (TIBC), and low transferrin saturation.  Complete blood count (CBC) demonstrates microcytic hypochromic anemia with low hemoglobin and hematocrit.  Differential diagnosis includes anemia of chronic disease, thalassemia, and sideroblastic anemia.  Further investigations may include fecal occult blood test, colonoscopy, esophagogastroduodenoscopy (EGD), and evaluation for celiac disease and other malabsorption syndromes as clinically indicated.  Treatment plan includes oral iron supplementation ferrous sulfate or other iron preparations.  Patient education provided on iron-rich foods and dietary modifications.  Follow-up scheduled to monitor ferritin levels, hemoglobin, and hematocrit, and to assess response to therapy.  ICD-10 code K50.9 (Iron deficiency anemia, unspecified) and ICD-10 code R53.83 (Weakness) may be applicable depending on individual presentation.  CPT codes for laboratory tests include 85018 (Complete blood count), 84175 (Serum iron studies), and 82270 (Fecal occult blood test).  Referral to hematology or gastroenterology may be considered depending on underlying cause and clinical course.