If follow-up testing cannot be obtained right away, the patient should consider taking at least 1000 mcg of B-12 per day on the chance that it is needed. If deficiency is causing the damage, sufficient doses of B-12 will stop the damage and eventually allow some degree (sometimes 100%) of recovery over time.

If testing is done after B12 has been taken, the results will probably be normal; that does NOT mean that the person was not deficient prior to taking the vitamin or will not become deficient again if it is stopped.
B12 is safe and inexpensive. Too little of it is very dangerous.

rose