Thanks for your question. If the blood test you had was to test for coeliac disease, it’s important to check that this was conducted under the right conditions – ie you need to have been eating gluten/ wheat-based foods regularly (at least 1 meal every day for minimum 6 weeks) prior to testing, otherwise your blood result may be falsely negative. If you believe the result to be accurate then it could be that you are suffering from gluten/ wheat sensitivity rather than coeliac disease, however this doesn’t explain the tolerance for Special K and biscuits, particularly if you are reacting badly to other similar-sized portions of wheat-containing foods. Your tolerance for vinegar is less surprising, the barley contained within vinegar is heavily refined and hence most gluten/ wheat-intolerant patients can tolerate this product. It sounds like some more detective work is needed. I’d suggest you ask your GP for a referral to registered gastroenterology dietitian who will be able to conduct a detailed analysis of your diet and symptoms, and hopefully give you some clearer advice and what foods you need to avoid.