How accurate is a blood test for tb? and is tb cure able or still fatal ? i have chronic cough 4 months weight loss night sweat very weak .

It's accurate...: in theory some people may not have enough of an immune response to anything to be able to have a positive test. For this reason similar tests to other things people are likely to have a reaction to are included in a positive control called an anergy panel (it's never worked for me) and a chest x-ray is another good screen indicated in every chronic cough that always has.