SpecimenWhole blood (1 mL) collected in a lavender-top (EDTA) tube.
Absolute count: 50 to 500 cells/microL [SI units (0.05–0.5 × 109/L)]
Relative percentage: 1% to 4%
This procedure is contraindicated for
Assist in the diagnosis of conditions such as allergies, parasitic infections, drug reactions, collagen diseases, and myeloproliferative disorders.
Eosinophils are released and migrate to inflammatory sites in response to numerous environmental, chemical/drug, or immune-mediated triggers. T cells, mast cells, and macrophages release cytokines like interlukin-3 (IL3), interlukin-5 (IL5), granulocyte/macrophage colony–stimulating factor, and chemokines like the eotaxins, which can result in the activation of eosinophils.
- Addison’s disease (most commonly related to autoimmune destruction of adrenal glands)
- Drug reactions
- Hay fever
- Hodgkin’s disease
- Hypereosinophilic syndrome (rare and idiopathic)
- Löffler’s syndrome (pulmonary eosinophilia due to allergic reaction or infection from a fungus or parasite)
- Myeloproliferative disorders (related to abnormal changes in the bone marrow)
- Parasitic infection (visceral larva migrans)
- Rheumatoid arthritis (possibly related to medications used in therapy)
- Aplastic anemia (bone marrow failure) Eclampsia (shift to the left; relative to significant production of neutrophils) Infections (shift to the left; relative to significant production of neutrophils) Stress (release of cortisol suppresses eosinophils)
- Numerous drugs and substances can cause an increase in eosinophil levels as a result of an allergic response or hypersensitivity reaction. These include acetophenazine, allopurinol, aminosalicylic acid, ampicillin, butaperazine, capreomycin, carisoprodol, cephaloglycin, cephaloridine, cephalosporins, cephapirin, cephradine, chloramphenicol, clindamycin, cloxacillin, dapsone, epicillin, erythromycin, fluorides, gold, imipramine, iodides, kanamycin, mefenamic acid, methicillin, methyldopa, minocycline, nalidixic acid, niridazole, nitrofurans (including nitrofurantoin), NSAIDs, nystatin, oxamniquine, penicillin, penicillin G, procainamide, ristocetin, streptokinase, streptomycin, tetracycline, triamterene, tryptophan, and viomycin.
- Drugs that can cause a decrease in eosinophil levels include acetylsalicylic acid, amphotericin B, corticotropin, desipramine, glucocorticoids, hydrocortisone, interferon, niacin, prednisone, and procainamide.
- Clotted specimens should be rejected for analysis.
- Specimens more than 4 hr old should be rejected for analysis.
- There is a diurnal variation in eosinophil counts. The count is lowest in the morning and continues to rise throughout the day until midnight. Therefore, serial measurements should be performed at the same time of day for purposes of continuity.
Nursing Implications and Procedure
- Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
- Patient Teaching: Inform the patient this test can assist in diagnosing immune response conditions and parasitic infections.
- Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
- Obtain a history of the patient’s hematopoietic, immune, and respiratory systems; symptoms; and results of previously performed laboratory tests and diagnostic and surgical procedures.
- Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values).
- Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Note that there are no food, fluid, or medication restrictions unless by medical direction.
- Potential complications: N/A
- Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
- Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
- Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
- Promptly transport the specimen to the laboratory for processing and analysis.
- Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
- Nutritional Considerations: Consideration should be given to diet if food allergies are present.
- Instruct the patient with an elevated eosinophil count to report any signs or symptoms of infection, such as fever.
- Instruct the patient with an elevated count to rest and take medications as prescribed, to increase fluid intake as appropriate, and to monitor temperature.
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
- Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
- Related tests include allergen-specific immunoglobulin E, biopsy bone marrow, blood gases, CBC, culture stool, ESR, fecal analysis, hypersensitivity pneumonitis screen, IgE, lung perfusion scan, ova and parasites, plethysmography, and PFT.
- Refer to the Hematopoietic, Immune, and Respiratory systems tables at the end of the book for related tests by body system.