How to Read Our Allergy Test

A common question we have gotten over the past three design reviews was some variation of "How do you read the test results?". Normally, allergy tests produce small bumps on the arm called wheals and each allergen has a control bump (if there is a reaction or not) that is about 2-3mm in diameter. A positive reaction would then have a wheal size of up to 5 mm in diameter on average. The wheals can easily be seen by the eye and these sizes are measured using calipers. In our device, however, the needles are much smaller and we are scaling down the dosage of the allergens. Through research, we have found out that this change would only scale down the size of the reaction. For example, instead of a 2-3 mm control size, it might be 0.2-0.3mm (if scaled down by a factor of 10, for example). Then the reaction size might only be about 0.5 mm, which is very small. We proposed using the same caliper measuring method, but adding in a magnifying glass, so the wheals can be seen better. Many people were also skeptical about this method if we were to have a large amount of allergens in our matrix (between 10 and 40, for example).

However, after discussing with Professor Wong about this issue, she explained that the main purpose of our device is to reduce the pain of having an allergy test. Although it is important to have to read the results, we should focus on the device and how the microneedles reduce pain, not necessarily on the reading of the results. If our only design goal was to reduce the pain of having an allergy test, then all we would have to do is show that we could get the microneedles to administer a test with less pain. Therefore, we could include only 2 allergens (2 microneedle clusters on the array) just to make our point. She also mentioned how the reading of the test could also be considered a project of its own and we should just prove the pain-free administration of the test.

Therefore, I think that it is best if we just focus on making the physical/mechanical aspects of the device work and then state that by magnifying the test area, the results can be read. I also think we should address the matrix size/allergen location confusion by creating a "legend" with the microneedle arrays. I think we should have something similar to what is on a box of chocolates to say which type of chocolate is where: just a map that can be used to match the allergens to their location. In order to do this, I think we need to make the matrix not a square so the legend can still be helpful for any orientation of the array.

These are just some of the ideas I had for this one comment we seem to keep getting after design reviews and we can consider them for the final product and presentation.