BasoFunction Test
Adverse reactions to drugs and chemicals may not be detected by specific IgE testing or skin tests. The BasoFunction test measures histamine released in vitro following challenge with a suspected allergen in patients. This test is indicated for patients with a history of adverse reactions who cannot be tested by conventional methods.
Peripheral blood leukocytes are enriched from heparinized whole blood and stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP), allergen or buffer alone. Following a brief incubation, the amount of histamine released from the basophils into the supernatant is measured by ELISA. FLMP is a nonspecific stimulus that determines the activation potential of the patient’s basophils. Approximately 5 to 10% of individuals have a low response indicating hypo-responsive basophils.
The amount of histamine (ng/mL) released following stimulation with a specific allergen is reported. Patients with values above these thresholds are sensitized and should be further evaluated before administration of drug therapy. The sensitivity and the true predictive value of the test is unknown for most drugs, and caution must be exercised with regard to patients who are non-responders to a suspected allergen. The allergen may still cause a clinically significant adverse reaction.
This is a laboratory developed assay performed at Viracor-IBT Laboratories. The list of potential allergens that can be tested include analgesics, anesthetics, antibiotics, food additives, contrast media and other chemicals. Reference ranges were determined on a population of healthy controls that had responsive basophils and no history of adverse reactions to the indicated allergens. Reference ranges vary for each allergen.
Specimen requirement is a green top tube of blood. Patients taking calcineurin inhibitors should stop their medication for 72 hours prior to draw. Patients taking prednisone should stop medication for 2 weeks before draw.
