Tingling can occur due to malabsorption of many things. The number one thing people seem to talk about is B12.
I've noticed that if I supplement magnesium mine will stop. There are other possibilities too.
Tests can turn up negative for many, many reasons:
Here's a good article:
http://f1.grp.yahoofs.com/v1/sMuXRgV...tion%20Ever%21