Evidence map›Paper›PMID 41787528›Full record

ReviewJournal of medical case reports2026

Diagnostic challenge of high vitamin B12 levels: a case report and review of the literature.

Matteo Stella, Renato Alberto Sinico, Francesca Margherita Panvini, Alessandro Manca, Francesco Reggiani, Marta Calatroni, Salvatore Badalamenti, Giovanni Covini

Abstract readCase ReportsReview
In one paragraph

Review in Journal of medical case reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Matteo StellaNephrology and Dialysis Division, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy. matteo.stella@humanitas.it.ORCID http://orcid.org/0009-0006-2990-8620
Renato Alberto SinicoNephrology and Dialysis Division, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.
Francesca Margherita PanviniClinical Laboratory, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.
Alessandro MancaClinical Laboratory, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.
Francesco ReggianiNephrology and Dialysis Division, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.
Marta CalatroniNephrology and Dialysis Division, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.
Salvatore BadalamentiNephrology and Dialysis Division, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.
Giovanni CoviniInternal Medicine and Liver Unit, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano - Milan, Italy.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundVitamin B12 (cobalamin) deficiency is a well-documented clinical condition, with several causes and important consequences. High serum B12 level (hypercobalaminemia) is less common and not easily explained, being caused by different conditions, such as blood disorders, autoimmune diseases, and solid tumors. Moreover, cases of increased B12 levels due to the presence of polymers formed by vitamin B12 and other proteins have been described to show falsely elevated serum levels when measured by conventional methods. CASE PRESENTATION: A 47-year-old white Italian man presented to an internal medicine ward complaining a sensation of a swollen tongue and upper limb paresthesias. Laboratory tests showed an increased level of cobalamin in the blood (6173 pg/ml); excessive cobalamin intake, solid tumors, autoimmune diseases, and hematological disorders were excluded. The use of polyethylene glycole precipitation allowed for the detection of macro-B12, a polymer composed of B12 and high-molecular-weight proteins, such as antibodies. The true value of vitamin b12 in the blood of our patients was normal.

conclusionHigh serum B12 levels may be due to a wide range of conditions, including severe diseases; when high levels of vitamin B12 are detected, it is useful to perform a screening for the most well-known conditions associated with this finding. The use of methods such as polyethylene glycole precipitation consent to identify the possible presence of a macro-B12.

Indexed as

ParesthesiaVitamin B 12Vitamin B 12 DeficiencyHumansMaleMiddle AgedVitamin B 12Case reportHypercobalaminemiaMacro-B12Polyethylene glycoleVitamin B12

Identifiers

PMID41787528
PMCPMC13072505

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.