Labs in different countries report differently.
Vit B6 is also reported as 5-30 nanograms/milliliter for "normal"
(I don't know the conversion to nanomoles as reported in Monica's post).

Labs choose ranges based on statitistics of an average of what they consider "normal"...these ranges are often different and
should be reported with the results. People often don't realize that the "normal" range is pretty arbitrary.

I think most vitamin testing is iffy myself. The very high and very low numbers suggest something, with the middle range meaning very little. This is because some people REQUIRE more than others. In the case of B6..there is a condition called B6 dependency, which means that those patients require much more than "normal".
http://emedicine.medscape.com/article/985667-overview

Also autistic patients often test high for B6 even when they do not use supplements. This is thought to be due to faulty conversion to P5P in the liver, and the pyridoxine just accumulates in the serum. But the true explanation is still unknown with certainty.

Metabolic differences between people exist and can be significant.