How accurate are blood tests for B12 vitamin when not fasting?

Accurate. We pathologists are focused on labs. In testing for B12 deficiency, we're looking largely at the ability to absorb it, and perhaps at its absence in the diet (even modest vegetarians are prone to be low). A non-fasting serum B12 in the normal range would reassure me and i'd not ask for a repeat fasting.

Related Questions

My 7yr old son recently had blood tests and all are normal except B12 is high. It was over 1200. Not taking any vitamins and gp not following up.

Look at reference. In the US, the reference range for it B12 for this age is 250-1205 pg/ml. Therefore, if I were to advise on this matter, I would say his level is normal. There are no particular reasons for concerns in mildly elevated levels. Most of the clinical problems arise from inability to absorb this vitamin from the GI tract or in certain extreme diets such a vegan diets without supplementation with B12. Read more...
That's fine. An isolated high B12 never means anything. Reference ranges are set so that a few percent of healthies fall outside on either end. Junior has a slightly increased amount of B12 carrying protein. Relax and be glad he's healthy. Read more...

Was deficient in vit d and B12 few years ago, would it be a good idea to check other vitamin blood tests like b3 or c or e to check cause of fatigue.?

Maybe. Fatigue has many causes. A visit with your health care provider might provide insight into the reason(s) you are fatigued. Vitamin deficiencies are not the most common causes of fatigue. Read more...
Not really. B12 deficiency may be dietary or related to gastric disease. Vitamin d is both absorbed and converted in the liver and skin to active forms. Vitamin c, e and others do not have the same absorption pathways nor the same actions. Vitamin k as an example is related to clotting, while e can help skin collagen deposition. They are all different and unique in function and action. Read more...

4 year old has speech delay, we did blood tests and Vitamin D was 14, B12 was 1200 and IgE was 192, every other tests normal, can these cause delay?

Speech. No. Speech is usually a developmental issue. Make sure his hearing is fine and get him to a speech therapist for a full evaluation. . Read more...
Speech Delay. Evaluation for speech delay typically includes a good neuro exam including hearing, dysmorphic screen., MRI, EEG and aphasia assessment. perinatal and developmental history are reviewed. pediatric Neurobehavioral assessment may also include screening for specific developmental or degenerative disorders. The b12 is OK. Vit D 25-OH level should be 30-100 range. Read more...