• Serum ferritin is the most sensitive indicator of total body iron stores.
• Above-normal ferritin results from excessive iron supple- mentation; inflammation; liver disease; and hemochromato- sis (iron storage disease).
• Below-normal ferritin levels result from inadequate dietary intake of iron.
Box 4.10 Laboratory Tests: Folate and Vitamin B-12
• Folate and vitamin B-12 are indicators of nutritional status and are also ordered to determine the cause of macrocytic anemia (when a CBC shows large red blood cells and decreased hemoglobin concentration).
• Deficiencies can cause altered mental status. • Above-normal B-12 and folate result from pernicious ane- mia and liver dysfunction.
• Below-normal B-12 and folate result from malnutrition, alcohol abuse, vegetarian dietary intake, celiac disease, and Crohn’s disease.
Box 4.11 Laboratory Tests: Hematocrit (Hct) and Hemoglobin (Hgb)
• Above-normal Hct and Hgb result from dehydration. • Below-normal Hct and Hgb result from malnutrition and iron deficiency.
