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. 2024 Apr 10;13(8):2176. doi: 10.3390/jcm13082176

Table 2.

Expert consensus was reached after two survey cycles on all of the following topics related to treatment, prophylaxis, and long-term B12 deficiency.

Question n (Panelists) 1 Mean (95% CI) 2
1. At present, it is unclear whether different forms of B12 differ in their effectiveness or safety. Clinical trials comparing the safety and effectiveness of the commercially available forms are needed. 42 0.88 (0.74–0.96)
2. Regarding the use of prophylactic B12 supplementation:

  • Patients with atrophic gastritis may benefit from prophylactic B12 supplementation.

 41 0.85 (0.71–0.94)

  • People at risk of B12 deficiency due to illnesses or medications should be recommended to use prophylactic B12 supplementation.

 41 0.85 (0.71–0.94)

  • People who underwent bariatric surgery in the past should receive B12 therapy or prophylactic B12 supplementation for long-term.

 41 0.90 (0.77–0.97)

  • People with low or no consumption of animal source foods should receive prophylactic B12 supplementation.

 42 0.83 (0.69–0.93)

  • People ever diagnosed with B12 deficiency, should receive prophylactic B12 supplementation when they decide to become pregnant.

 39 0.85 (0.69–0.94)
3. There is no one-size-fits-all regarding the dose of B12, the frequency and the route of B12 therapy in people with B12 deficiency. Regarding the decision on the route of B12 administration:

  • Higher degrees of acuity and severity of symptoms should lead to prioritizing parenteral B12 treatment over oral treatment.

 38 0.87 (0.72–0.96)

  • Contraindications of intramuscular injections such as concurrent anticoagulant medication can lead to prioritizing oral B12 treatment.

 32 0.75 (0.57–0.89)

  • The decision on the route of B12 administration should consider patients’ preference that may change during long-term treatment.

 40 0.78 (0.62–0.89)
4. If B12 treatment fails in symptomatic patients, one or more of the following measures are recommended:

  • Consider alternative diagnoses that may explain the patient’s symptoms.

 40 0.98 (0.87–0.999)

  • Check if the B12 dose was appropriate.

 39 0.95 (0.83–0.99)

  • Switch to parenteral B12 if oral B12 treatment was used in the past and plasma B12 has not been normalized.

 38 0.87 (0.72–0.96)
5. B12 deficiency during pregnancy, lactation and in infancy needs to be detected and treated as early as possible because of the serious effects of B12 deficiency on fetal and infant development. 38 0.89 (0.75–0.97)
6. Women with a previously diagnosed B12 deficiency or dietary restriction of animal foods should take prophylactic B12 supplementation from pre-pregnancy to the end of the lactation period. 38 0.92 (0.79–0.98)

1 Total number of the panelists who answered each of the questions. 2 Mean percentage and the 95% confidence intervals of the panelists who considered themselves qualified to answer the question and chose “agree” or “strongly agree” to the answer. We considered that a consensus was reached when the lower bound of the 95%confidence intervals is 50% or higher.