I am 34 year old woman, my hands and feet tingling always when i sit down for just few minutes.? in blood report its nothing.

Spinal issue?: Hand and feet nerve symptoms can manifest themselves during activity and/or rest. In your case, it might be the loading vertically of the spine when sitting that causes the lumbar and brachial plexus to be compressed, causing a nerve entrapment. Seek out a spinal surgeon or neurologist for more definitive testing and examination.

One would not : Expect a nerve problem to be found in a blood result. It is a diagnosis that possibly can be confirmed with emg/ncv studies, though there are many false negatives. A clinical exam clambake the diagnosis as well. Sometimes, x-ray findings can show arthritic type changes which we know would cause nerve related symptoms.

Not sure: Peripheral neuropathy can be from many things. It may not show up on a blood test. See a neurologist and ask questions.