Hi rach985 the perceived wisdom in other countries such as Japan and the U.S is to treat Vitamin B12 Deficiency under 500 so your readings definitely fall into a "grey area" as highlighted below under the heading "Types of tests for B12 Deficiency" talking about the Serum Vitamin B12 Test American professionals say:-
"However, it appears that these markers demonstrate B12 deficiency primarily in patients whose serum B12 is in the "gray zone" (a serum B12 result between 200 pg/ml and 450 pg/ml). We believe that the "normal" B12 threshold needs to be raised from 200 pg/ml to at least 450 pg/ml because deficiencies begin to appear in the cerebral spinal fluid (CSF) below 550 pg/ml
At this time, we believe normal serum B12 levels should be greater than 550 pg/ml. For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1,000 pg/ml."
Anyone at any age, can become B12 deficient. However, certain people are at an elevated risk. They include the following:
Vegetarians, vegans and people eating macrobiotic diets.
People aged sixty and over
People who’ve undergone any gastric and/or intestinal surgery, including bariatric surgery for weight loss purposes (Gastric bypass).
People who regularly use proton-pump- inhibitors. H2 blockers, antacids, Metformin, and related diabetes drugs, or other medications that can interfere with B12 absorption.
People who undergo surgeries or dental procedures involving nitrous oxide, or who use the drug recreationally.
People with a history of eating disorders (anorexia or bulimia).
People with a history of alcoholism.
People with a family history of pernicious anaemia.
People diagnosed with anaemia (including iron deficiency anaemia, sickle cell anaemia and thalassaemia).
People with Crohn’s disease, irritable bowel syndrome, gluten enteropathy (celiac disease), or any other disease that cause malabsorption of nutrients.
People with autoimmune disorders (especially thyroid disorders such as Hashimoto’s thyroiditis and Grave’s disease) Type 1 diabetes, vitiligo, lupus, Addison’s disease, ulcerative colitis, infertility, acquired agammaglobulinemia, or a family history of these disorders.
Women with a history of infertility or multiple miscarriages. Do you see yourself in any of the above people? If you do make a list of the "possible causes" together with your symptoms and present it to your doctor and ask him to treat you in accordance with the BNF Guidelines - a copy of which he should have on his desk as follows:-
Treatment of cobalamin deficiency
"Current clinical practice within the U.K is to treat cobalamin deficiency with hydroxocobalamin in the intramuscular form outlined in the British National Formulary, BNF,
Standard initial therapy for patients without neurological involvement is 1000 μg intramuscularly (i.m.) three times a week for two weeks, then every three months.
The BNF advises that for Pernicious anaemia and other macrocytic anaemias patients presenting with neurological symptoms should receive 1000 μg i.m. on alternative days until there is no further improvement, then 1 mg every 2 months.
However, the GWG recommends a pragmatic approach in patients with neurological symptoms by reviewing the need for continuation of alternative day therapy after three weeks of treatment"
Your doctor should be treating you, the patient, according to your neurological symptoms and not just looking at the computer screen and reading "Normal" Test ranges are based on the "average" person and we are not all average.
I am not a medically trained person but one who has had Pernicious Anaemia for 45 years and I'm still "clivealive" at 75.