They say one cannot consume too much B6 with the food. And I don't remember myself ever supplementing with B6. And yes, I know that an excess of B6 is toxic for the nerves. I read one theory that too much B6 in serum means not enough of it in the tissues. So they advice to take the big doses of B6 to get it into the tissues. And what about more toxicity for the nerves?
Also information on B6 is somewhat contradicting: it causes neuropathy when you have too much of it but it also causes neuropathy when you are deficient. Sigh...

Too high B6 might not be what you think:

The Cause of Vitamin B6 Toxicity is Not What You Think

The suggestion is to take activated B6 called P5P to help.
People may not convert B6 pyridoxine, to active P5P, for several reasons.
1) genetic failure of pyridoxal kinase in the liver

2) low levels of B2 riboflavin which is a cofactor of pyridoxal kinase,

3) use of certain drugs, including caffeine which block conversion.
Near the end of this paper (starting at page 63), is a list of drugs they found so far that block pyridoxal kinase activity. The list is growing by the year, as more drugs are tested for this effect.
http://scholarscompass.vcu.edu/cgi/v...07&context=etd

Suffice it to say something is preventing activation of B6 to P5P for some people, so they test high as the INactive B6 builds up in the body.

Hi MrsD,

Actually the name of the B6 test I have done is:

Vitamin B6 (Pyridoxal-5' phosphate (PLP))

If I understand it right - this is already an active P5P form of the B6 found in excess in my blood serum. Correct me if I am wrong. Thank you.

You mentioned taking extra B6, so I think you should use
P5P supplement form.

This topic is still unresolved IMO. You can Google many medical sites including those with real doctors who answer questions.

I found one doctor who just said stop eating things/ supplements with B6 in them. I saw another who said elevated serum B6 comes from dying liver cells.
There are patients claiming levels 10x normal down to twice normal. There are many people over the years asking this question and I have still have not seen definitive answers to this question.

The neuropathy of toxicity (typically from high dose use for long periods of pyridoxine) is more affecting of proprioception and gait.

This is a list from Medscape:
from: Vitamin B6: Reference Range, Interpretation, Collection and Panels

These symptoms are different and more serious than sensory neuropathy.

Sometimes labs make mistakes. Sometimes results are confounding . It is possible that if the specimen is mishandled, the red cells may lyse (burst) and the contents spill into the serum causes false elevations in the tests. Potassium is another nutrient that can give false elevations due to lysed cells.

Red blood cells do convert pyridoxine to P5P so if they burst after drawn from the subject, they would release P5P into the serum.
Conversion of vitamin B6 compounds to active forms in the red blood cell

So I do think that the test may have confounding weaknesses, involving lab errror or mishandling of the sample.
Doctors don't usually respond to elevated B6 levels, but only to the very low results.

Look at your diet. Energy drinks, energy bars, breakfast cereals can contain substantial B6.

At this point the B6 is probably not an issue for you.

Using a methylcobalamin supplement may be useful for you,
since your test was marginally low. 400 is the new cut off for deficiency now.

And I'd consider getting the DNA MTHFR test. It may reveal an error in metabolism for you.