Good Lord Holly you should be in a tiny ball writhing on the floor at 170...200 is the cut off point of being too low...
Normal serum B12
range, newborns3 160 - 1300 pg/ml
range, adultsA 200 - 900 pg/ml
average 450 pg/ml
And to add to your paranoia.......
psychotic depression is more often caused by Vitamin B12 Deficiency than by any other known or unknown cause. This fact is hardly ever borne in mind when psychiatrists confront a case of psychotic depression and, when they do think of it and order a serum B12 level, they will more often than not still miss the deficiency because the lab "normal range" is so low that their patient's B12 level almost always appears to be in the "normal range".
At least six neurological and psychiatric papers, in top medical journals, have shown that the normal range should be regarded as at least 500-1,300 pg/ml (rather than 200-1,100), since the cerebrospinal fluid level can be deficient when the serum level drops below 500, and neuropsychiatric symptoms often occur at serum levels between 200 and 500 pg/ml (VanTiggelen et al, Lindenbaum et al, Mitsuyama/Kogoh, Nijst et al, Ikeda et al, Regland). As for the still held misconception that the neuropsychiatric effects of Vitamin B12 Deficiency are always accompanied by a macrocytic anemia, it is humbling to know that this notion was already debunked in 1905 (Langdon)! Since then, many papers have stressed this point, including those by Strachan and Henderson (1965), Evans et al (1983) and Lindenbaum et al (1988).
....
Pat