USA Pernicious Anaemia Information

Key Guidance on Pernicious Anemia and Vitamin B12 Deficiency in the U.S.
American Academy of Family Physicians (AAFP) – Vitamin B12 Deficiency: Recognition and Management (2017)

Diagnosis:
Initial tests include a complete blood count (CBC) and serum vitamin B12 level.
A serum B12 level <150 pg/mL (111 pmol/L) is diagnostic for deficiency.
For asymptomatic high-risk patients with low-normal B12 levels, measure serum methylmalonic acid (MMA) to confirm deficiency, as it is a more sensitive marker.
If Pernicious Anemia is suspected (and no dietary or malabsorption cause is evident), test for anti-intrinsic factor antibodies (positive predictive value = 95%). An elevated serum gastrin level can also support the diagnosis.

Treatment:
For Pernicious Anemia, intramuscular (IM) vitamin B12 injections (cyanocobalamin or hydroxocobalamin, 1000 mcg) are recommended, typically weekly for 4 weeks to replenish stores, then monthly for life.

American Gastroenterological Association (AGA) – Autoimmune Gastritis and Pernicious Anemia (2021)

Key Recommendations:
Pernicious anemia is characterized by vitamin B12 deficiency due to autoimmune destruction of gastric parietal cells, leading to intrinsic factor deficiency.
Patients newly diagnosed with Pernicious Anemia should undergo endoscopy with topographical biopsies to confirm corpus-predominant atrophic gastritis and rule out gastric neoplasia (e.g., neuroendocrine tumors).
Lifelong vitamin B12 supplementation (typically IM injections) is required.
Patients should be educated about the increased risk of gastric cancer and the association with other autoimmune disorders (e.g., type 1 diabetes, thyroid disease).

National Heart, Lung, and Blood Institute (NHLBI) – Vitamin B12 Deficiency Anemia (2022)

Key Recommendations:
Pernicious anemia is a common cause of B12 deficiency in the U.S., particularly in individuals of northern European or African descent.
Diagnosis involves blood tests (CBC, serum B12 levels) and, if needed, additional tests like MMA or anti-intrinsic factor antibodies.
Treatment includes vitamin B12 supplements (oral, nasal spray, or IM injections). For pernicious anemia, IM injections are preferred initially (1000 mcg weekly for 4 weeks, then monthly).

Cleveland Clinic – Pernicious Anemia and Vitamin B12 Deficiency (2023, updated 2024)

Key Recommendations:
Diagnosis involves a thorough medical history, physical exam, and lab tests (CBC, serum B12, reticulocyte count, lactate dehydrogenase, and anti-intrinsic factor antibodies).
Pernicious anemia requires lifelong B12 supplementation, typically via IM injections (hydroxocobalamin or cyanocobalamin, 1000 mcg monthly after initial repletion).
Oral supplementation (1–2 mg daily) may be considered for maintenance in some cases, with close monitoring.
Patients should be monitored regularly for B12 levels and symptoms, especially if neurological symptoms (e.g., numbness, tingling) are present.

Medscape – Pernicious Anemia Treatment and Management (2024)

Key Recommendations:
Initial treatment: IM cyanocobalamin or hydroxocobalamin (1000 mcg daily for 1 week, then twice weekly for 4–5 weeks) to replenish stores, followed by monthly injections for life.
If folic acid deficiency coexists, treat with both folic acid and B12 to prevent neurological damage from unaddressed B12 deficiency.
Family members of patients with pernicious anemia should be monitored due to increased familial risk.