Test Overview

A blood sample is used to screen for foods that a patient has a delayed allergic reaction to. In addition to providing information on which foods may trigger an untoward immune response in the patient, the test also indirectly indicates the integrity of the intestinal mucosa (i.e. screens for "leaky gut syndrome").

Test Indications

Sample Collection

Your doctor will draw the blood sample or refer you to a blood draw facility in your area. Sample collected in Red top Serum Separator Tube, full tube. Allow to clot at room temp for 15-30 minutes. Centrifuge for 15 minutes and separate the serum from the cells. Decant or pipette serum into transport vial. Refrigerate sample until ready to ship.

Your doctor or lab may have different instructions that supersede the above.

CPT CODES

CPT-CodeDescriptionComments
86001*93  

Labs Performing Test

Name of LabLab CodeEstimated CostProcessing TimeComments
Great Plains  $219+draw fee2-3 weeksCash discount and some insurance

Costs cited are subject to change and may be reduced by insurance or cash discounts and increased by sample collection fees.

Theory

There are different types of "hypersensitivity" or allergic reactions.

Immediate hypersensitivity reactions are typically mediated by IgE immunoglobulin produced by B-cells, which binds to mast cells, basophil cells, and eosinophil cells. These types of allergic reactions are typically observed within minutes of an exposure, such as hay fever and peanut allergies. The "skin-prick" test is often used to screen a patient for immediate hypersensitivity reactions to pollens and foods.

Delayed hypersensitivity reactions are typically mediated by IgG immunoglobulin produced by B Cells. These types of allergic reactions may manifest 2 or more hours after an exposure, and for this reason the patient often has little awareness of cause and effect. Many food allergies are IgG-mediated.

In addition to food allergies, some patients have food sensitivities that are caused by some metabolic defect that prevents proper digestion or processing of some component of the food. These are properly called "intolerances" instead of "allergies" as they are not mediated by IgE or IgG. An example is "lactose intolerance" in which the patient has a deficit of the enzyme "lactase" and is unable to digest and absorb the "milk sugar" lactose. Since the lactose in milk cannot be digested and absorbed, it remains in the gut and feeds an overgrowth of microflora, which in turn causes symptoms.

The reliability of IgG food allergy testing has been called into question due to different results being reported by different labs, and due to imperfect correlation between lab reports and patient response to foods. Despite these limitations, IgG food allergy testing is an important tool in designing food elimination diets that can be further refined by the clinical response of each patient.

In some cases, a patient will give a test response to most of the foods in the patient's diet. This is an indication of "leaky gut syndrome" in which case a loss of integrity of the intestinal mucosa is allowing undigested foods to enter the patient's blood stream, causing a general arousal of the immune system. Many autoimmune and chronic illnesses are due in part to this mechanism. In this case, avoiding the allergenic foods may give symptomatic relief, while healing the gut is necessary to resolve the cause.


References

Unless specifically noted above, references used in the construction of this web page include the following:

[FDM] Lecture notes from Functional Medicine University.

[SCNM] Lecture notes from Southwest College of Naturopathic Medicine.

[UT] Lecture notes from the University of Tennessee graduate programs in Chemistry and Biochemistry.

[GP] Great Plains Laboratory Physician Training lecture notes and documentation.