What Does A Anti-Gliadin Result Of "Negative", But >0, Mean?

[Traveller]

I looked at my blood test results again and became puzzled. The test result page says results less than twenty are negative, twenty to thirty a weak positive, and above thirty positive. What supports this breakdown?

I understand that there is no generally accepted test for gluten sensitivity. Some doctors think gluten sensitivity does not exist, others go by a positive anti-gliadin blood test, some accept a positive stool test, and some rely on dietary elimination and reintroduction. Others rely on a combination of factors, which may or may not include the blood test. With that being the case, it's difficult to understand the negative/positive in blood tests results as equalling a gluten sensitivity yes/no. So the negative positive must mean something else.

I've also learned that many lab tests with a "normal range" are not based on health, but on all tests given by the lab in a period of time, after dropping of the top and bottom 5% (or some similar algorythym). Is the anti-gliadin test result range determined similarly?