Food Detective - FAQs: Technical & Clinical
Do I need to completely fill up the capillary tube with blood? Yes, it is advisable to completely fill the tube as this gives an exact amount of blood required for the test. If you do not fill the tube, then it is possible that any positive results will be weaker than they should be because of a greater dilution of the blood sample.
What volume of blood is needed for the test?
50 microlitres whole blood are needed for the test (the capillary tube measures this amount precisely).
I don’t seem to be able to collect enough blood to fill the capillary tube, what should I do?
In the unusual circumstances when there is insufficient blood to fill the capillary tube, and both of the lancets provided have been used, then it may be necessary to telephone CNS for a replacement tube and lancets. It is important to make sure that your hands are warm and that you have massaged your sample finger thoroughly before using the lancet. Wipe your finger/thumb with the antiseptic wipe and allow the finger to dry. Hold the lancet firmly against the finger before pricking with lancet. This allows a good droplet of blood to form on the finger before touching the capillary tube against the droplet to collect the blood. Take care that the other end of the tube is not covered. It is advisable to open the test tray once you have obtained your blood sample. It may be easier to obtain the blood sample with the help of a friend.
Do I have to collect the blood sample at any particular time of day?
No, samples can be collected at any time of the day.
What if there are air bubbles present when I add the blood sample to the tray?
When the diluted blood sample is added to the plate, any air bubbles that are present should be dislodged by gentle tapping of the tray.
What do the controls tells me?
The positive control needs to be blue, and the negative control needs to be white at the end of the test, for the results to be valid.
Do I need to use all of the reagent in each bottle?
The volumes of solutions supplied with the kit are sufficient to adequately cover the surface of the reaction tray. It will not make any significant difference if one or more drops are not added from the bottle provided the whole bottom surface of the tray, (including the circles), are covered.
I have been avoiding a food for more than 3 months; will this food show up in the test?
It is possible that the antibody levels will have reduced significantly if you have been completely avoiding that food, and therefore highly likely that the food test will be unable to detect any antibodies. If you wish to test whether you can now tolerate the food concerned and feel that you can cope with the symptoms that may occur, include a portion of that food every day for 1 week before taking the blood sample. If you experience severe symptoms as a consequence, you should stop eating that food immediately and assume that you are still intolerant to it.
Will any drugs affect the results?
Immunosuppressants which are generally given following an organ transplant will reduce the immune system’s ability to generate antibodies. High doses of steroids will also affect antibody production. If you are in any doubt, please consult your GP.
What is an IgG?
IgG stands for Immunoglobulin (type G). Immunoglobulins are a class of proteins that function as antibodies produced by the immune system in response to foreign bodies entering the body. There are several different types of immunoglobulins with IgA, IgE, IgG, IgM being the most well known.
What is an antibody, and what is the difference between IgG and IgE antibodies?
An antibody is a specialised protein produced by the body’s immune system when foreign bodies (such as viruses, bacteria and toxins) enter the body. They are produced by special white blood cells called B-Lymphocytes as a defence against these foreign substances. IgE antibodies are a type of antibody mostly found in the skin, nose, lining of airways and lungs, and are usually produced in classical allergies. IgG antibodies are the type of antibodies that CNS tests. It has been shown by various studies, that if foods producing high IgG levels are eliminated from the diet, the symptoms of can be reduced.
Why do foods cause an IgG response?
Generally, foods are broken down during digestion into their component parts e.g. amino acids, glycerides etc. These pass harmlessly through the gut into the bloodstream. However, occasionally small fragments of partially digested or undigested foods are able to pass through the gut wall into the bloodstream where they are recognized by the immune system as being ‘foreign’. The immune system responds by making antibodies (IgGs).
Why do high IgG antibody levels cause symptoms?
When a food causes the body to produce high levels of IgG then these antibodies combine with the protein in the food to form an ‘antigen-antibody complex’. These complexes are usually eliminated by other cells in the immune system. However, if the immune system is overloaded, these insoluble moleculesbecome deposited in tissues within the body, causing chronic inflammation and the subsequent production of symptoms.
Is it possible to have high IgG levels and not experience symptoms?
Yes, some people do have high IgG levels to certain foods but do not have any symptoms at all. This is possibly due to their immune system being extremely efficient at clearing away the antigen-antibody complexes before they have chance to be deposited in the tissues and cause a problem.
What is Leaky Gut syndrome?
In some patients, inflammation or irritation of the intestinal lining allows partially digested foods to leak through gaps between cells in the intestinal wall into the bloodstream. This condition is called ‘leaky gut syndrome’ and patients with this condition typically have high levels of antibodies to multiple foods. The symptoms of Leaky Gut Syndrome are many and varied and include: abdominal pain, heartburn, insomnia, bloating, anxiety, gluten intolerance, malnutrition, muscle cramps and pains, poor exercise tolerance, food allergies.
Does a Leaky Gut need to be repaired before those foods can be eaten again without symptoms?
Yes. It is recommended that you consult a nutritionist who will provide dietary and supplementary advice to address a leaky gut.
Why does the Food Detective not test for sugar or alcohol?
Food intolerance is caused by the presence of proteins and the antibodies directed against them. Sugar and alcohol are carbohydrates and do not provoke an antibody response.