Questions & Answers

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    ImmunoCAP Rapid. Results direct, clear and simple

ImmunoCAP Rapid is a ready-to-use test with pre-selected allergens in accordance with symptoms and age. All reagents needed are included in the kit, together with Directions for Use. You will find answers to the most frequently asked questions here.

 

Sample | Assay Procedure | Interpretation of results | Allergens 

Sample

Q1

Which types of lancets should be used?

The blood volume required in the assay is quite high (110 µl), so lancets that provide a good blood flow should be used.

Q2

How critical is the volume of blood added to the Blood Sample Well?

Tested volumes of 110 µl ± 10 % (100-120 µl) have been found to work.

Q3

How long can the blood sample be stored in the Blood Sampling Device?

The sample can be stored up to 5 minutes in the Blood Sampling Device without being affected.

Assay Procedure

Q4

If the Assay Device has been stored unprotected without the foil pouch, can it be used?

Internal studies have shown that the Assay Device is stable for 1 hour at room temperature.

Q5

According to the DFU, the first incubation time (separation step and sample incubation) is 5 minutes, after which the Developer Solution should be added. How critical is the first incubation time?

The first incubation time has been tested from 5-7 minutes and found to work. The risk of blood leakage will probably increase with time, differing between individual samples and haematocrit levels.

Q6

How critical is the volume of Developer Solution added (500 µl)?

Internal studies have shown that results are not affected over the 450-550 µl interval for Developer Solution added.

Interpretation of results

Q7

If there are no pink-red Control Lines after the assay time is completed, what do I do?

The Assay Device has not been working properly. The patient should be re-tested with a new Assay Device.

Q8

Must the test results be read immediately the assay procedure is completed?

Internal studies have shown that results are not significantly affected up to one hour after completion of the assay procedure. However, the risk of blood leakage into the Test Window/Windows will increase with time.

Q9

Why is there a difference in the intensities of the coloured pink-red lines indicating positive test results?

There is an overall relationship between the intensities of the pink-red colour lines and the concentrations of allergen-specific IgE antibodies in samples. However, due to the complexity of both allergen composition and each patient's immune response, the relation between colour and IgE antibody concentration may differ from sample to sample.

Q10

Why are positive test results sometimes obtained for t9 (olive pollen) among the northern European population, which is not usually exposed to olive pollen?

a

One explanation might be different cross-reactions between trees and plants.
Ash (Fraxinus), lilac (Syringa) and privet (Ligustrum), trees that are present in the northern European region, belong to the same family (Oleaceae) as olive (Olea). Some cross-reactivity between the species could therefore be expected.

On exposure to other tree pollens within the same family, antibodies to common specific allergen structures in the species have been produced, giving positive t9 results in ImmunoCAP® Rapid (see picture below).

The picture also includes some other examples of possible cross-reactions similar to the example described above. 

b

Antibodies to profilin (a common allergen structure in pollens) might give positive results to some or all pollens included in ImmunoCAP® Rapid.

Exposure and sensitization to t3 – common silver birch (Betula verrucosa) – might in these case result in positive results for some or all pollen allergens in ImmunoCAP® Rapid, including t3 (see picture below). 

 

Q11

Why are positive test results sometimes obtained for d1 (house dust mite, Dermatophagoides pterinyssinus) and i6 (cockroach, Blatella germanica) when there is no known exposure to i6?

Tropomyosin is an allergenic component that might be responsible for cross-reactivity between cockroach and house dust mite.

Allergens

Q12

What lies behind the choice of allergens on ImmunoCAP® Rapid Wheeze/Rhinitis Child?

The product has been developed for children at various ages with allergy-like symptoms such as wheeze and/or rhinitis.

  • The rationale for including egg and milk in the profile is that there are reports indicating a link between food sensitization and asthma/wheeze in the youngest children.
  • With increasing age, sensitization to indoor allergens such as cat, dog and house dust mite starts to play a more important role.
  • As the child gets older, outdoor allergens such as pollens from grasses, weeds and trees become more important factors behind allergy symptoms such as rhinitis and asthma/wheeze.

The selected allergens are suitable for children in both southern and northern Europe.

Q13

What lies behind the choice of allergens on ImmunoCAP® Rapid Asthma/Rhinitis Adult?

The product has been developed for adult patients with allergy-like symptoms in the respiratory tract, such as rhinitis and asthma.
In adult allergic patients with respiratory symptoms, inhalant allergens are the dominating triggers. There are reports that indoor allergens are more often responsible for allergic asthma, and outdoor allergens are more prevalent among allergic patient with upper respiratory tract symptoms.
The chosen allergens are relevant for both southern and northern Europe.

Q14

Are the allergen raw materials used in ImmunoCAP® Rapid the same as those in ImmunoCAP® Specific IgE?

The allergen raw materials used in ImmunoCAP® Rapid are basically the same as those in the ImmunoCAP® Specific IgE tests, but each individual allergen has been optimized for the ImmunoCAP® Rapid technology.