Identification of the cause of PN can be a long & costly testing process.
It is done by a process of elimination-no one test will dx PN.
The odds of finding your cause is very small. You must be persistent and
be willing to undergo many tests over a long period of time.
That said, treatment is basically the same for 95% of all the different PN causes.......unless you have CMT or Autoimmune, or inherited (gene testing) PN.
If I were you, I'd be sure my glucose GTT testing for pre-diabetes is done, & have Gluten intolerance testing done.
(www.lizajane.org ...has all the tests for PN, and a downloadable
chart to track the test results.)