Synonym/Acronym
Retic count.
Rationale
To assess reticulocyte count in relation to bone marrow activity toward diagnosing anemias such as pernicious iron deficiency, and hemolytic anemia; to monitor response of therapeutic interventions.
Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.
Normal Findings
Method: Automated analyzer, flow cytometry smear.
| Age | Reticulocyte Count % |
|---|
| Newborn | 3%–6% | | Infant | 0.4%–2.8% | | Child | 0.8%–2.1% | | Adult–older adult | 0.5%–2.5% | | Reticulocyte Count (Absolute Number) | | Birth–2 wk | 0.0396–0.1375 (106 cells/microL) or 39.6–137.5 K/microL | | 2 wk–older adult | 0.047–0.152 (106 cells/microL) or 47–152 K/microL | | Immature Reticulocyte Fraction % | | Birth | 2.5%–6.5% | | Newborn–older adult | 2.5%–17% | | Reticulocyte Hemoglobin | | Birth | 22–32 pg/cell | | Newborn–18 yr | 23–34 pg/cell | | Adult–older adult | 30–35 pg/cell |
|
Study type: Blood collected in a lavender-top [EDTA] tube; related body system: Circulatory/Hematopoietic system.
Normally, as it matures, the red blood cell (RBC) loses its nucleus. The remaining ribonucleic acid (RNA) produces a characteristic color when special stains are used, making these cells easy to identify and enumerate. Many automated cell counters have the ability to provide a reticulocyte panel, which includes the enumeration of circulating reticulocytes as an absolute count and as a percentage of total RBCs; the immature reticulocyte fraction, which reflects the number of reticulocytes released into the circulation within the past 24 to 48 hr; and the reticulocyte hemoglobin content, which reflects the amount of iron incorporated into the maturing RBCs. The presence of reticulocytes is an indication of the level of erythropoietic activity in the bone marrow. The information provided by the reticulocyte panel is useful in the evaluation of anemias, bone marrow response to therapy, degree of bone marrow engraftment following transplant, and the effectiveness of altitude training in high-performance athletes. In abnormal conditions, reticulocytes are prematurely released into circulation. (See studies titled “RBC Count, Indices, Morphology, and Inclusions.”)
Factors That May Alter the Results of the Study
- Drugs and other substances that may increase reticulocyte counts include acetylsalicylic acid, amyl nitrate, antipyrine, arsenicals, corticotropin, dimercaprol, etretinate, furazolidone, levodopa, methyldopa, nitrofurans, penicillin, procainamide, and sulfones.
- Drugs and other substances that may decrease reticulocyte counts include azathioprine, dactinomycin, hydroxyurea, methotrexate, and zidovudine.
- Reticulocyte count may be falsely increased by the presence of RBC inclusions (Howell-Jolly bodies, Heinz bodies, and Pappenheimer bodies) that stain with methylene blue.
- Reticulocyte count may be falsely decreased as a result of the dilutional effect after a recent blood transfusion.
Other Considerations
- Specimens that are clotted or hemolyzed should be rejected for analysis.
The reticulocyte production index (RPI) is a good estimate of RBC production. The calculation corrects the count for anemia and for the premature release of reticulocytes into the peripheral blood during periods of hemolysis or significant bleeding. The RPI also takes into consideration the maturation time of large polychromatophilic cells or nucleated RBCs seen on the peripheral smear: RPI = % reticulocytes × [patient hematocrit (Hct)/normal Hct] × (1/maturation time)
As the formula shows, the RPI is inversely proportional to Hct, as follows:
| Hematocrit (%) | Maturation Time (day) |
|---|
| 45 | 1 | | 35 | 1.5 | | 25 | 2 | | 15 | 2.5 |
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Increased In
Conditions that result in excessive RBC loss or destruction stimulate a compensatory bone marrow response by increasing production of RBCs.
Decreased In
- Anemia of chronic disease
- Aplastic anemia(related to overall lack of RBC)
- Bone marrow replacement (new marrow fails to produce RBCs until it engrafts)
- Endocrine disease (hypometabolism related to hypothyroidism is reflected by decreased bone marrow activity)
- Kidney disease(diseased kidneys cannot produce erythropoietin, which stimulates the bone marrow to produce RBCs)
- RBC aplasia (related to overall lack of RBCs)
- Sideroblastic anemia(RBCs are produced but are abnormal in that they cannot incorporate iron into hemoglobin, resulting in anemia)
- Substance use disorder (alcohol) (decreased production related to nutritional deficit)
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
- Discuss how this test can assist in assessing for anemia.
- Explain that a blood sample is needed for the test.
- Discuss the symptoms of anemia: pallor, dizziness, weakness, irritability, anxiety, poor concentration, tingling, numbness, shortness of breath, cold sensitivity, palpitations.
After the Study: Implementation & Evaluation Potential Nursing Actions
Nutritional Considerations
- Discuss the inclusion of iron-rich foods in the diet: dried fruits, green leafy vegetables, legumes, egg yolks, seafood, whole grains, nuts, meats (especially liver), and multivitamins with iron.
- Note: Animal liver (e.g. beef, chicken, deer, lamb) is a nutrient-dense food. Micronutrients, with the exception of vitamin D, are not produced by the body; they must be obtained from dietary sources. Liver is a rich source of vitamins and minerals, most notably providing significant amounts of iron, copper, folate, vitamin A, and vitamin B12. Regularly eating large amounts of animal liver can result in vitamin A toxicity and/or damage to the patient’s liver. The general recommendation commonly given by health-care providers to adult patients is to consume no more than one to three and a half ounces (28 to 100 gm) of liver, once a week. Recommended portions depend on age and gender. Patients should also be aware of vitamin and mineral concentrations contained in dietary supplements that are taken regularly.
Treatment Considerations
- Review the pathophysiology as applies to diagnosed anemia.
- Discuss general causes of anemia; destruction of red cells, insufficient production of red cells, bleeding.
- Review potential therapeutic interventions as applies to clinical diagnosis; transfusion, iron and vitamin supplements (vitamin C, folic acid, B12), treatment of underlying cause of blood loss.
Clinical Judgement
- Consider how to relay the damage that anemia can present to overall health and longevity.
Follow-Up and Desired Outcomes
- Understands that depending on the results of this procedure, additional testing may be performed to evaluate or monitor disease progress and determine the need for a change in therapy.