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DESCRIPTIONAllergy refers to an acquired potential for developing adverse reactions that are mediated by the immune system (via IgE antibodies). Allergic disease represents the clinical manifestations of these adverse immune responses. An allergen is any substance that can cause an allergic reaction. Allergens are often common, usually harmless substances such as pollens, mold spores, animal danders, dust, foods, insect venoms, latex, and drugs.
The optimum management of the allergic patient should include a careful history and physical examination and may include confirming the cause of the allergic reaction by information from allergy tests.
Allergy tests considered clinically useful for allergy confirmation by the American Academy of Allergy, Asthma, and Immunology (AAAI) and the American College of Allergy, Asthma and Immunology (ACAAI) in the diagnosis and management of the allergic patient are addressed in the Allergy Testing policy. Once an allergy-causing agent is identified, treatment is provided by avoidance, medication, or immunotherapy.
This policy addresses only allergy tests of uncertain efficacy and those used primarily in research settings.
Allergy Tests of Uncertain Efficacy
Antigen leukocyte cellular antibody (ALCAT) automated food test
The ALCAT automated food test measures whole blood leukocytes by a proprietary process that identifies allergens which cause an increase in leukocyte activity. An electronic counter measures the change in number and size of white blood cells which have been incubated with purified food or mold extracts. A histogram is produced based on cell count and cell size. Individually processed test samples are compared with a "Master Control" graph. Scores are generated by relating these effective volumetric changes in white blood cells to the control curve.
Applied Kinesiology (or muscle strength test)
Muscle strength in the extremities is measured before and after a person is exposed to an allergen. Strength in the opposing arm is measured as a person holds a container of allergen extract in the opposite hand or ingests an allergen. A decrease in strength indicates the presence of disease and various nutritional supplements may be recommended.
Cytotoxic food tests
This test involves the response of specially collected white blood cells to the presence of food extracts to which the patient is allergic. A technician observes the unstained cells for changes in shape and appearance of the leukocytes. Swelling, vacuolation, crenation, or other cytotoxic changes in cell morphology are taken as evidence of allergy to the food.
Electrodermal testing (also known as electro-acupuncture)
Electrodermal testing measures changes in skin resistance while a person is exposed to an allergen, either food or inhalant. This allergy-testing device uses a galvanometer to measure the electrical resistance of the skin. A drop in the resistance of the skin is believed to indicate the presence of allergy.
Hair is analyzed for the presence (or lack) of various minerals and toxins. Findings are correlated to nutritional deficiencies or disease. Recommendations for diet and supplements are provided based on the analysis.
IgG/IgG4 antibody test and food specific IgG/IgG4 tests
There are 4 subclasses of immunoglobulin G. Selective deficiencies in one or more of the 4 IgG subclasses are seen in some patients with repeated infections. Measurements of IgG and specifically IgG4 antibodies have been used in research settings as diagnostic and prognostic tests to determine response to allergy treatments.
According to the AAAI, iridology attempts to relate the anatomical features in the iris to various systemic diseases.
Passive transfer of P-X (Prausnitz-Kustner) test
This technique involves prick, scratch, or intradermal transfer of serum from a sensitized individual into a nonallergic volunteer. The volunteer is then challenged with the allergen by skin testing. A wheal or a flare response indicates a positive reaction. This procedure is now considered obsolete and has been replaced by the Radioallergosorbent Test (RAST) test.
Provocative-neutralization tests for food (or food additive allergy test)
This procedure is performed by injecting (intradermal or subcutaneous), or placing under the tongue (sublingual), dilute extracts of the suspected food or inhalant allergen and observing the patient’s response or reaction. A symptomatic response indicates an allergy to that food or inhalant, and the reaction can be neutralized by application of a similar extract of a lesser dilution.
Rebuck skin window test
This is a type of skin testing where the skin surface is stripped or broken to cause serious oozing. This area is then covered by a glass plate, coated with the allergen to be tested, and taped in place for 24 hours. At the end of that time the plate is removed, and the cells under the plate and the surrounding skin are checked for any changes. An eosinophilic exudate typical of an allergic reaction appears in the area of the stripped epidermis. The results are very difficult to interpret and are not practical for general use. The procedure is no longer in use.
Allergy Tests in the Research Setting
Conjunctival challenge test
With conjunctival testing, an allergenic extract is placed into the conjunctival sac of the eye followed by observation for redness, itchiness, tearing of the eye, and other similar symptoms. According to the AAAI, these tests are often used in research protocols that require an objective standard for evaluating clinical sensitivity to an allergen.
Leukocyte Histamine Release Test (LHRT)
In this testing, leukocytes from the serum of an allergic individual are observed for histamine release in the presence of an antigen. The commercial availability of simplified and automated methods of laboratory analysis have renewed interest in the clinical applications of LHRT in the evaluation of food, inhalant, and drug allergies. The AAAI guidelines for this test indicate it is primarily used in a research setting.
Nasal challenge test
This test provides precise measurements of changes in nasal airway resistance along with observations such as number of sneezes and measurement of inflammatory mediators in the nasal secretions after exposure to an allergen. The more commonly known "sniff test," uses a visual assessment of mucosal swelling and rhinorrhea after a small amount of dry pollen is inhaled.
POLICYThe following allergy tests are considered investigational as the scientific evidence does not permit conclusions regarding their effects on health outcomes:
1. Antigen leukocyte cellular antibody (ALCAT) automated food test
2. Applied kinesiology allergy test
3. Conjunctival challenge test (ophthalmic mucous membrane test)
4. Cytotoxic food tests
5. Electrodermal testing (also known as electro-acupuncture)
6. Hair analysis
7. IgG/IgG4 allergen specific antibody test and food tests
9. Leukocyte histamine release test (LHRT)
10. Nasal challenge test
11. Passive transfer or P-X (Prausnitz-Küstner) test (now considered obsolete-and replaced by Radioallergosorbent tests)
12. Provocation-neutralization food or food additive allergy test
13. Rebuck skin window test (no longer in use)
POLICY GUIDELINESInvestigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
POLICY HISTORY11/17/2011: Approved by Medical Policy Advisory Committee.
04/24/2013: Policy reviewed; no changes.
SOURCE(S)Regence Allergy Tests of Uncertain Efficacy Medical Policy
CODE REFERENCEThis may not be a comprehensive list of procedure codes applicable to this policy.