not lactose intolerant but still can't have lactose?

I recently had a lactose intolerance breath test and it was negative.  However, whenever I have lactose I feel bloated and constipated - more than usual (I have IBS-Constipation Type).  Is it possible to not be lactose intolerant and still have difficulty digesting foods containing lactose? .

[CalGal]

There are two major components in dairy - the lactose and a protein called casein. Often, when someone has a diary issue, it's automatically assumed it's lactose-intolerance when it may not be. The culprit could be the casein. If you want to find out, have your doc run a fecal antibody test for casein issues. The fecal antibody test is more accurate than the blood test which can often come up negative when in fact it should be positive. You can also do the test yourself. Check it out at enterolab.com.

[FuturePA]

That's interesting.  I never knew that there was a specific test for caesin. I wonder why doctors don't perform that test especially on someone like myself who exhibits all the textbook signs of lactose intolerance but tested negative on the breath test.  Thanks for the input.  I will discuss it with my doctor.

[FurballsMom]

Yes, the casein.  And, I was going to add that you can test negative for other things and still react to them.  Closely related to the casein issue is gluten intolerance.  I test negative to gluten and struggle to prove to some Dr. Doubter that I really can't eat gluten, but the fact of the matter is, I can't eat gluten and I do react badly to it.  So, keep in mind that you can still test negative for things and still not be able to eat them.