Algorithm(s)
PDF algorithm(s) available at www.arupconsult.com.
Anemia Testing Algorithm
Clinical Background
Anemia is characterized by decreased red blood cell mass, causing symptoms resulting from tissue hypoxia.
Definition (WHO)
- Males - hemoglobin <13 g/dL (at sea level)
- Females - hemoglobin <12 g/dL for nonpregnant females (at sea level)
Epidemiology
- Incidence - 29-30/1,000 females; 6/1,000 males <45 years; 18.5/1,000 males >75 years
- Age - different age peaks dependent on etiology of anemia
- Sex - F>M during childbearing years
Classification
- Based on morphology of red blood cell (rbc)
- Mean cell volume (MCV)
- Low MCV - microcytic
- Normal MCV - normocytic
- High MCV - macrocytic
- Mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC)
- Low MCH/MCHC - hypochromic
- Normal MCH/MCHC - normochromic
- Based on red blood cell production rate (measure of hemolysis)
- Measured by reticulocyte count
- Reticulocyte count formula (with correction for anemia):
- Reticulocyte Count % (Hgb/Htc) (1/maturation time correction*)
- *Maturation time correction is usually 2 for most patients
Pathophysiology
- Macrocytic
- Drug effect (hydroxyurea, azido-thymidine [AZT])
- Nutrient deficiency - folate and/or B12
- Hemolysis
- Hypothyroidism
- Excessive alcohol use
- Myelodysplasia
- Normocytic
- Blood loss
- Hemolysis
- Renal insufficiency
- Chronic disease (inflammatory or malignant)
- Bone marrow infiltration
- Hemoglobinopathies
- Microcytic
- Iron deficiency
- Chronic disease (inflammatory or malignant) occurs in a minority of the cases
- Thalassemia
Clinical Presentation
- Acute loss - hypotension, tachycardia, confusion, diaphoresis
- Chronic loss - fatigue, pallor, lack of stamina, breathlessness
- Younger patients - may not have clinical symptoms until anemia is severe
- Older patients - may first manifest with angina, dyspnea
Treatment
- Based on diagnosis
- For acute loss - may require transfusion to maintain circulation
See Also
Algorithm(s)
PDF algorithm(s) available at www.arupconsult.com.
Anemia Testing Algorithm
Diagnosis
Diagnosis
- Laboratory testing
- CBC with red blood cell indices combined with cell morphology on peripheral smear
- Reticulocyte count
- Further testing based on results of CBC and reticulocyte count
- Total iron binding capacity (TIBC), serum iron, serum ferritin
- Bone marrow biopsy may be needed
Algorithm(s)
PDF algorithm(s) available at www.arupconsult.com.
Anemia Testing Algorithm
Tests generally appear in the order most useful for common clinical situations
| Test name: CBC with Platelet Count & Automated Differential
|
| ARUP #: 0040003 |
| Methodology: Automated Cell Count with Flow Cell Differential
|
Use: Identify the presence of anemia Establish indices of morphology |
| Test name: Reticulocytes, Percent & Number
|
| ARUP #: 0040022 |
| Methodology: Flow Cytometry
|
| Use: Identify presence of immature red blood cells |
| Test name: Iron & Iron Binding Capacity
|
| ARUP #: 0020420 |
| Methodology: Spectrophotometry/Calculation
|
| Use: Identify iron deficiency |
| Test name: Ferritin
|
| ARUP #: 0070065 |
| Methodology: Chemiluminescent Immunoassay
|
| Use: May be useful in combination with other tests of iron status in differentiating iron deficiency anemia from anemia of chronic disease |
Additional Tests Available
| Test name: Soluble Transferrin Receptor
|
| ARUP #: 0070283 |
| Methodology: Immunoturbidimetric
|
| Comments: |
| Test name: Transferrin, Serum
|
| ARUP #: 0050570 |
| Methodology: Immunoturbidimetric
|
| Comments: |
| Test name: Hemoglobin, Serum
|
| ARUP #: 0020057 |
| Methodology: Spectrophotometry
|
| Comments: |
| Test name: Hemoglobin
|
| ARUP #: 0040085 |
| Methodology: Automated Flow Cytometry
|
| Comments: |
| Test name: Manual Differential
|
| ARUP #: 0040005 |
| Methodology: Microscopic
|
| Comments: |
| Test name: Hematocrit
|
| ARUP #: 0040080 |
| Methodology: Automated Cell Counter
|
| Comments: |
References
General References
Brill JR, Baumgardner DJ. Normocytic anemia. Am Fam Physician.
2000;
62(
10):
2255-2264.
Davenport J. Macrocytic anemia. Am Fam Physician.
1996;
53(
1):
155-162.
Killip S, Bennett JM, Chambers MD. Iron deficiency anemia. Am Fam Physician.
2007;
75(
5):
671-678.
Little DR. Ambulatory management of common forms of anemia. Am Fam Physician.
1999;
59(
6):
1598-1604.
Shine JW. Microcytic anemia. Am Fam Physician.
1997;
55(
7):
2455-2462.
Steensma DP, Tefferi A. Anemia in the elderly: how should we define it, when does it matter, and what can be done?. Mayo Clin Proc.
2007;
82(
8):
958-966.
Tefferi A. Anemia in adults: a contemporary approach to diagnosis. Mayo Clin Proc.
2003;
78(
10):
1274-1280.
Tefferi A. Practical algorithms in anemia diagnosis. Mayo Clin Proc.
2004;
79(
7):
955-956.
Weiss G, Goodnough LT. Anemia of chronic disease. N Engl J Med.
2005;
352(
10):
1011-1023.
References from the ARUP Institute for Clinical and Experimental Pathology Research®
Auerbach M, Rodgers GM. Intravenous iron. N Engl J Med.
2007;
357(
1):
93-94.
Laman CA, Silverstein SB, Rodgers GM. Parenteral iron therapy: a single institution's experience over a 5-year period. J Natl Compr Canc Netw.
2005;
3(
6):
791-795.
Rodgers GM. Guidelines for the use of erythropoietic growth factors in patients with chemotherapy-induced anemia. Oncology (Williston Park).
2006;
20(
8 Suppl 6):
12-15.
Medical Reviewers
Lehman, Christopher M., M.D. Co-Medical Director, University Hospital Clinical Laboratory; Associate Professor, Clinical Pathology, University of Utah
Roberts, William L. , M.D., Ph.D. Medical Director, Automated Core Laboratory at ARUP Laboratories; Professor, Pathology, University of Utah
Rodgers, George M. III, M.D., Ph.D. Medical Director, Hemostasis/Thrombosis at ARUP Laboratories; Professor, Medicine, Adjunct Professor, Pathology, University of Utah
Comprehensive Review: May 2008
Last Update: May 2008
