You want a B12 level in the upper quarter of range or above, and anything below midrange should be particularly suspicious if you are symptomatic. B12 levels can come up quickly, within weeks, although it can take months to years to recover from symptoms, depending upon severity and duration of deficiency. If you have started supplementing before testing, you may not be getting an accurate reading. In those with B12 deficiency, oral doses of at least 1000mcg are needed, which equates to 16,667% of RDA. It sounds huge, but if one lacks intrinsic factor (due to pernicious anemia) or has a malabsorption problem, it is the required dose.
I have met many other B12ers over the years and have been impressed by how many had similar symptoms. Still, not everyone will have the same symptoms or have all the symptoms.
The heart and urinary tract symptoms came first for me, sporadically over 3-4 years. The rest started coming at a rapid pace over 6-12 months before finding my low normal B12 level of 294 (150-1100) in Sept 2000. My symptoms resolved for the most part within the first several months, but some things improved slowly over 1 or 2 years time.
Gone are my many idiopathic, benign, and somatic illness diagnoses~ including idiopathic premature ventricular contractions (PVC's), benign paroxysmal positional vertigo (BPPV), "possible" Menieres, Restless Leg Syndrome (RLS), Benign Fasciculation Syndrome (BFS), "irritable" bladder, anxiety, GERD.
It took 3 years and 8 specialists before one thought to check my B12 level, but I am thankful the neuropsychologist who did recognize that a low normal B12 level was significant!
This is the list of my symptoms when I was B12 deficient:
Irregular heart rhythms (skipped/delayed beats, flutters, weird beats that took my breath away, exaggerated pounding, racing heart..."idiopathic PVC's")
Urinary tract stabbing pain and numbness (repeated episodes-never infection..often felt like someone was poking a needle in me)
Urinary urgency and frequency, discomfort on urination
Nocturia (having to get up at night to urinate)
Frequent yeast infections (three in eight months prior to dx-none since)
Dizziness- little waves all the time, when I turned head, stood up, etc
Shooting and stabbing/piercing pains in chest, back of head, and later just about everywhere
Blurred vision and dimness, aching and numbness of eye socket, stabbing pain behind eyeball–mostly R eye; wavy vision (mirage ripples) and trailing lights; dry gritty feeling eyes; whole upper right quadrant of face felt numb
Burned feeling at tip of tongue
Constant twitches all over my body (about every 3 seconds at worst)
Thumb or toe would move back and forth for hours at a time
Buzzing sensations- mild all over, intense shooting/buzzing down my legs (mostly R~ vibration could be felt by others)
Sporadic leg jerks Muscles cramping, short and long in duration
Dropped things...keys, cups, soda can would randomly drop out of my hands
Brain fog- cognitive difficulties in concentration, memory, word finding- thinking at all! Couldn't follow conversation of others; lost train of thought mid sentence..a lot. Wrong words popped out frequently. Couldn't remember days or times of routine events.
Disorientation - A couple of times while driving, could not remember how to get to where I was going. Momentarily "lost" in very familiar surroundings. Yep... scary!
Aching forearm and wrist with stabbing pain; stiff hands had trouble moving hand/fingers to write
‘Spot’ pain and numb spots in spine, also buzzing in those spots
Numb/buzzing spot on scalp
Little ‘bee sting’ pains all over– deep but pinpoint
Itching - especially on my back along my spine.
Buzzing, humming, crackling and painful pressure in ears
Muffled hearing..sounded like they were plugged..but they were "fine" on physical exam.
Vertigo attacks- feeling of rocking back and forth and in and out, not so much spinning, but very off balance, rocking boat sensations... kept me from daily activities Ataxia?
Feeling of dropping from the sky while sitting still
Shooting ‘chill’ sensations from neck down spine
Middle of the night panic attacks (just woke to them a couple of times)
Uncontrolled shivering even when it wasn't cold
Legs and arms would fall asleep with least bit of pressure on them
Weakness...it was difficult to blow dry my hair..holding up the hairdryer was difficult!
Fatigue- which got worse initially upon supplementation
GERD/burning stomach/pain after every meal/episodic diarrhea (this has completely vanished gluten free, although the stomach symptoms had already improved alot just from taking B12 and fish oil)
Goldman: Cecil medical textbook --- Saunders 2000 page 865
TABLE 163-4 -- NEUROPSYCHIATRIC
ABNORMALITIES * THAT MAY BE CAUSED BY COBALAMIN DEFICIENCY
B12 deficiency and Cognitive Decline
WELL, I GUESS I AM NOT ALONE
From Wrong Diagnosis website: