Indications for cobalamin level assessment in departments of internal medicine: a prospective practice survey

Abstract

Traditional indications did not perform better than other indications observed in current practice for identifying low Cb levels among inpatients from internal medicine departments. Future studies are needed to establish robust guidelines for inpatient screening.

Elevated Vitamin B12 Levels and Cancer Risk in UK Primary Care: A THIN Database Cohort Study

“…B, IRR after 1 year of follow-up. Previous studies suggest that in up to two thirds of individuals with a plasma B12 measurement, there was no specific indication for requesting the measurement, such as symptoms and/or risk factors for B12 deficiency (24,25). The higher IR within the first year of follow-up even for patients with B12 within the reference range may be due to the effect being in diagnostic process (i.e., the reason plasma B12 was measured).…”

“…To overcome this limitation, we identified a cohort of first-time statin users in the main study population, assuming that these individuals: (i) are unlikely to be suspected of cancer; (ii) have blood samples taken regularly as a part of the routine statin check-up recommended for new statin users by the National Institute for Health and Care Excellence (https://www.nice.org.uk/guidance/ cg181/; accessed December 7, 2018); and (iii) are likely to have their plasma B12 levels measured without an indication of any suspected severe disease. Previous reports indeed indicate that B12 is often measured without any indications related to symptoms and/or risk factors for B12 deficiency (24,25). The inclusion criteria for this cohort were a first-time statin prescription, and a plasma B12 measurement within 6 months after the date of the first statin prescription.…”

Sensory Neuronopathy Revealing Severe Vitamin B12 Deficiency in a Patient with Anorexia Nervosa: An Often-Forgotten Reversible Cause

“…To be reasonably sure that total serum B12 is adequate, some have proposed to consider as correct only levels above ~400 pmol/L [11,12]. Especially below that cut-off, as in our case, confirmatory tests are needed to assess adequacy of functional B12: measurement of methylmalonic acid, or in folate-replete patients, total homocysteine [8]. The worsening under folate therapy was also evocative of the process termed the ‘folate trap’ [13].…”

“…To date, B12 deficiency has not been included among the classical causes of sensory neuronopathies, which usually have an acute onset, are sometimes asymmetrical, or have a non-length-dependent distribution [6]. Importantly, the fact that B12 serum levels assessment can be falsely normalized by various medical conditions (including acute and chronic liver diseases, often of alcoholic origin, various neoplasias, malignant hemopathies such as myeloproliferative diseases, and renal insufficiency), a situation often termed as “functional B12 deficiency”, may have participated to the underdiagnosis of this association [7,8]. Indeed, in the cases where the serum levels are in the normal range but the index of suspicion for a B12 deficiency remains strong, the diagnosis should rely on either surrogate biomarkers for B12 deficiency (high homocysteine or methylmalonic acid (MMA) levels, medullary aspiration findings) and/or on the improvement under B12 supplementation.…”

“…Indeed, in the cases where the serum levels are in the normal range but the index of suspicion for a B12 deficiency remains strong, the diagnosis should rely on either surrogate biomarkers for B12 deficiency (high homocysteine or methylmalonic acid (MMA) levels, medullary aspiration findings) and/or on the improvement under B12 supplementation. However, in practice, these additional investigations are rarely performed [8]. …”