Apologies in advance this is not an American reading
Gender: Female Age: 16
Serum Vitamin B12 and Folate studies
B12 (180-740) pmol/L - 797
R.CF ( > 630 ) nmol/L - 863
( if it helps I had a mild infection when I got this blood tests I also love steak and usually have 4-6 steaks a week grass fed beef and I eat canned salmon/tuna almost every day, ive heard these are quite high in B12, but apparently the cause for high B12 is rare from dietary sources? Because then the liver would just flush it out? )
The test is good at telling when somebody is B12 insufficient. An upper limit is set on the test only because a high value can, in the context of other tests, hint at liver function problems. If your liver enzymes (ALT, AST, etc.) were normal, then there is absolutely nothing to worry about.
To the best of my knowledge, there is no known risk associated with B12 repletion. A bigger problem is B12 malabsorption, so if the stores are full, that is a sign that everything is working as it should.
Take my own case: my last serum B12 test result was, literally: ">965 pg/mL". That's off-scale high.
With the stores full, if you are in good health and in the absence of chronic bleeding or other disease, you could stop eating any source of B12 today and you wouldn't show signs of deficiency for another 3 to 5 years. The body is that good at conserving B12.
Celebrate that you have achieved repletion through diet alone :)