If the blood test and biopsy were done at the same hospital and the blood test was positive and the biopsy was negative then it suggests you don't have celiac disease. The biopsy is the gold standard test for celiac disease.
The blood test could be positive for a variety of reason. As I recall there is a reasonably high occurrence of false positive blood test results sometimes caused by other disorders. So a positive blood test does not necessarily mean you have to avoid gluten and unfortunately there is no way to tell except by experimenting.
Something you might try doing is introduce a small amount of gluten containing food once each day for a few days and see how it goes. You might do this at the same meal each time so you can keep track of your progress. This might be the only way you can figure it out. If you decide to give it a try please tell us how it goes.
-------------------- STABLE: ♂, IBS-D 50+ years - Science of IBS