ANEMIA IN THE ELDERLY
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Clinical Overview |
| Laboratory Parameters |
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Laboratory Parameters in Anemia Diagnosis | |||
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Hemoglobin | |
Serum Ferritin | |
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Hematocrit | |
Serum Folate | |
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Total Reticulocyte Count | |
Serum Vitamin B12 | |
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Serum Iron | |
The Schilling Test | |
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Total Iron Binding Capacity (TIBC) | |
Serum Erythropoietin | |
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(open chart in new window -printable version)
| Laboratory Value | Normal Range | Measurement | Interpretation | Comments |
| Hemoglobin | M 13.5-17.5 g/dL F 12.0-16.0 g/dL |
The amount of hemoglobin in a volume of blood; represents its oxygen-carrying capacity | Reductions can be due to either a decreased quantity of hemoglobin per RBC or a reduction in the total number of RBCs13 | Males generally have a higher reference range due to some stimulation of RBC production by androgenic steroids. |
| Hematocrit | M 41.0-53.0% F 36.0-46.0% |
The percent volume of RBCs per unit of volume | A low hematocrit indicates a reduction in the size or number of RBCs or an increase in plasma volume. | |
| Total Reticulocyte Count | 0.5-1.5% | Estimates the rate of red blood cell production | Increases when erythropoiesis is stimulated (e.g. during hemolysis or in response to erythropoietin therapy)Decreases during bone marrow suppressions or leukemia.13 | Reticulocytes develop into mature RBCs, are larger in size than RBCs, and contain remnant nuclear material. |
| Serum Iron | M 50-160 mcg/dL F 40-150 mcg/dL |
The concentration of bound iron to transferrin, the iron transport protein; usually transferrin is about one-third bound or saturated.13 | Decreased in iron-deficiency anemia or anemia or chronic diseaseIncreased during hemolytic anemia and iron overload.13 | Iron-deficiency anemia may present with serum iron levels within normal range, resulting in a false negative.13 Therefore, serum iron levels alone are not adequate for diagnosis, and are best when interpreted with TIBC.13 |
| Total Iron Binding Capacity (TIBC) | 250-400 mcg/dL | TIBC is an indirect measure of serum transferrin. Percent transferrin saturation is the ratio of serum iron to TIBC (serum iron/TIBC x 100). | A low serum iron concentration and a high TIBC indicates iron-deficiency anemia.13 In iron-deficiency anemia, as the serum iron decreases and TIBC increases, the percent transferrin saturation will become less than 13 percent.13 | TIBC is determined by adding an excess amount of iron to the plasma to saturate all the transferrin. Any excess or unbound iron is then removed and serum iron concentration is determined. |
| Serum Ferritin | M 15-200 ng/mL F 12-150 ng/mL |
Ferritin, the storage iron, is proportional to total iron stores. | Low ferritin is diagnostic of iron-deficiency anemia, but may be normal in chronic inflammatory conditions.14Increased ferritin levels may indicate infection, inflammation, malignancy or liver disease. | |
| Serum Folate (red cell folate) |
1.8-16.0 ng/mL (RBC folate 140-640 ng/mL) |
Minimal daily requirement is 50-100 mcg. The body stores about 10-20 mg of folate, which last about four to six months, making dietary supplementation necessary.4,13 | Decreased folic acid levels may indicate a folate deficient megaloblastic anemia, possibly adjunctive to a vitamin B12 deficiency.13 | Folic acid is necessary for the production of nucleic acids, amino acids, proteins, DNA and RNA. Folate is usually found in dietary sources such as vegetables, fruit, yeast, mushrooms, and animal liver and kidneys.13 |
| Serum Vitamin B12 | 100-900 mcg/mL | Usual total daily requirements are 1-5 mcg and the body stores about 2-5 mg.13,15 The average diet contributes about 20 mcg of B12 daily such that it would take 3-4 years to develop a deficiency.13 | Low levels are indicative of a vitamin B12 deficient, megaloblastic anemia.13 | Vitamin B12 is water-soluble and usually found in meat and dairy products. Vitamin B12 is important for DNA synthesis, metabolic reactions with folic acid, and maintenance of the neurologic system.13 |
| The Schilling Test | In patients with vitamin B12 deficient anemia, is used to determine if the deficiency is due to impairment in B12 absorption caused by a lack of intrinsic factor, pernicious anemia. | Abnormally low levels of recovered cobalamin recovered indicate malabsorption or pernicious anemia; normal levels may indicate dietary insufficiency.15 |
Patients are administered cyanocobalamin intramuscularly on Day 1 to saturate intestinal mucosal cells followed by an oral dose of radiolabeled B12 on Day 2. Excess cobalamin that is not absorbed is excreted in the urine, and collected over 24 hours.15 | |
Serum Erythropoietin
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0-19 mU/mL | Measures the amount of the circulating hormone in blood, and is indicative of the body’s response to oxygenation levels. |
Increases of 100- to 1000-fold in patients with hypoxia or anemia. Large increases in patients with end-stage renal disease or receiving chemotherapy are not seen as their EPO response is not sufficient to correct the resulting anemia.13 | |
| Adapted from Greer JP, Rodgers GM, Foerster J et al. Wintrobe’s Clinical Hematology. 11th ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2004. | ||||
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Site Reviewed August 2007
