I would be wary of such a test since I noticed it said it cannot identify lactose intolerance or celiac disease. Also, it's not suitable for allergy detection, the company's website says.
If it's unable to pinpoint lactose intolerance, then I doubt it can spot casein (milk protein) sensitivity either. What's left for common dairy triggers? Nothing, as far as I'm aware.
I suggest trying a nutrition clinic such as tcufrog did if possible where you live or another in-person facility. It seems to me the testing and interpretation would be much more precise as well as giving you the opportunity to ask questions.
I was diagnosed with IBS over 20 years ago when pinpointing food allergies and intolerances was somewhat less evolved than today. Simple trial and error enabled me to determine that I'm gluten and casein intolerant. A food log of everything I ate was essential for me to narrow down what was triggering my flares although I was pretty sure dairy was involved. Lactose-free milk made no difference, nor did other animal milks.
Have you tried eliminating the most common allergens and then gradually reintroducing them one-by-one? Your own elimination diet? If not, that may be all you need to determine what you react to.