The blood test may be to test your thyroid, as carpal tunnel can be a symptom of under-active thyroid. I used to and sometimes still get the pins and needles you are talking about - and I have under-active thyroid caused by Hashimotos, I had the nerve conduction test to check for carpal tunnel but it came back negative - my mum had Carpal tunnel though and had an operation to widen the tunnel - which has helped.