Regarding blood levels of B6:

1) Studies have shown that in autistic patients, B6 can be elevated when NO vitamins are used.
2) also there is a factitious (false positive) for potassium. If the tourniquet is on too tightly, or the blood sample is handled wrong, the red cells can burst and release their potassium to give a higher than normal level, in the serum which is what is tested. I am wondering if this can happen with B6 which is inside red blood cells.
http://www.ajcn.org/cgi/content/abstract/50/5/1059
If the red cells break open during the blood draw or later due to poor handling, there could be a false positive high reading.
The only way to test this is to redo the test, and not use any supplement of any kind for many weeks before the blood sample is taken. If it remains high for no reason, that indicates either it is not being used by the body properly ..activated to pyridoxal, or is somehow a factitious reading.
I searched the net this morning again, and this question comes up on many other sites, and the typical answer, is "don't know".

If you stop all B6 and still have neuro symptoms, and a high reading in the blood serum, I'd consider using activated B6 called P5P. B6 is unusual because deficiency and excess gives similar symptoms, and this is very difficult to evaluate, if the testing procedure may be flawed.