Vitamin B12 deficiency: How to evaluate and treat it?

The prevalence of vitamin B12 deficiency (B12) is approximately 6-12% in people <60 years, and around 17% in all adults with macrocytic anemia. However, the elderly, pregnant women and vegans are more susceptible to B12 deficiency, so there should be a higher index of suspicion in populations that have suggestive symptoms and signs.