Please keep in mind that the percentages that were reported to you are not "hard" values but estimates and each has a confidence limit (or error factor) attached to it. The testing companies probably don't bother to make this clear since most do not understand the statistics involved, but it may be in the information that you received.

I don't have any specific information about the confidence limits of the test you took, but I suspect that is would be much larger then 2%. If that is the case, then your NA percentage would not be significantly different from zero.