Welcome to NeuroTalk:

If you start taking vitamins now, your testing will not reflect your status since the vitamins will show up as high.

It would be good to have B12, and D tested. Perhaps B1, and B6. If you have these measured, please bring the results here, as some doctors do not interpret the results accurately or usefully.

HbA1C to show average blood sugar levels.
Testing for immune globulins like IgM and IgG, IgA.
Testing for thyroid.
Fasting INSULIN to see if you have insulin resistance which is impaired glucose utilization (not yet diabetes).

Testing for Gluten intolerance. This dietary problem shows up in long standing neuropathies that are hard to figure out.
Testing information here: If you decide to test for this, you need to be eating gluten, so stopping it now is not advised.
http://neurotalk.psychcentral.com/thread1872.html

DNA test for MTHFR which is a genetic error, passed on that prevents normal methylation of folic acid and B12. If you cannot methylate these vitamins your nervous system starves in the mist of plenty (and the unmethylated ones will show up in testing as "normal"). Methylated B12 and folate are available OTC now without prescription.

Poor sleep may suggest that you are low in B12 for some reason,
a methylation error, or poor intake. MethylB12 is active in the brain and is the cofactor for making melatonin, our sleep hormone. If one is low in B12 then melatonin is not made and you do not sleep normally anymore.

There are special DNA tests for Charcot Marie Tooth genetic neuropathies. Here is a thread for that explaining:
http://neurotalk.psychcentral.com/thread121564.html
This is done at a special place, and is quite expensive. So keep that in mind.

Neuropathies that follow in families, may reflect Charcot Marie Tooth which makes them a primary factor.
Other neuropathies that are secondary to other disorders, may also follow in family lines, such as diabetes, autoimmune disorders (thyroid, lupus and others), and pernicious anemia.

There are OTC drugs and RX drugs that can cause PN. OTC ones are common-- acid blocking drugs, impair B12 absorption.
Antibiotics like Cipro and Levaquin are fluroquinolones, and Flagyl, damage nerves, sometimes for life. Using one of these drugs anytime in the past could damage you, and you would not even consider it, because doctors don't understand this fact or overlook it and won't admit to it.