Originally Posted by mrsD

I believe Stacy is meaning the "old" lab ranges showing low numbers as normal.

Also if you have inactive B12 in your serum from supplements, and you have the MTHFR genetic mutation that prevents conversion to active methyl form, you would test higher, and still the B12 would not be working. An MMA test will reveal if your B12 is working for you. Or you could get the DNA test for the MTHFR polymorphisms.

If you are taking B12 already, it will read high in testing serum.