Intended for healthcare professionals

Rapid response to:

Practice Easily Missed?

Pernicious anaemia

BMJ 2020; 369 doi: (Published 24 April 2020) Cite this as: BMJ 2020;369:m1319

Rapid Response:

Pernicious anaemia. Easily over-diagnosed? Increasing unnecessarily workload?

Dear Editor

The article by Mohamed et al [1] clearly raises awareness about the need to diagnose pernicious anaemia (PA), but fails to alert practitioners about one important issue, over-diagnosis and its consequences.

Two years ago, we reviewed the matter in our practices, collaboratively. We were concerned about patients not tested (no record of Intrinsic Factor (IF)) before the diagnosis was coded in the records. Audits were carried out to identify patients with the diagnosis and if the IF result was not available on the electronic health records they were re-tested when they came for their next B12 injection (just before, to avoid unequivocal results). All patients were treated with injectable B12.

Between the two practices, there were seventy-five patients initially identified with a diagnosis of pernicious anaemia (fifty one cases in one practice and twenty four in the other). After testing, diagnosis was confirmed in just twenty-three cases.

The reduction of fifty-two patients needing three-monthly injections (some requiring visits) reduced the number of appointments needed in a year by 156 in our two practices.

A different matter still controversial is whether PA treatment should be via injectable or oral supplementation. Inappropriate B12 therapy is unfortunately common [2]. Reasonable alternatives like starting the patient with oral B12 and monitoring adequacy before switching to injectable treatment [3] are not common practice even though it would reduce discomfort to patients and free time to clinical staff to treat others.

It is paramount to diagnose these patients, but to do so properly; so adequate and efficient management is implemented.

1. Mohamed, M., Thio, J., Thomas, R.S. and Phillips, J.P. Pernicious anaemia. BMJ, 2020; 369 doi:

2. Silverstein WK, Lin Y, Dharma C, Croxford R, Cheung M. Appropriateness of B12 Administration in a Real-World Population. Blood. 2018 Nov 29;132(Supplement 1):2227. doi:

3. Butler CC, Vidal-Alaball J, Cannings-John R, McCaddon A, Hood K, Papaioannou A, Mcdowell I, Goringe A. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials. Family practice. 2006 Jun 1;23(3):279-85. doi:

Competing interests: No competing interests

24 April 2020
P Millares-Martin
Dr R M Bobet-Reyes, Highfield Surgery,
Whitehall Surgery