Values from an immunoassay for total vitamin B12 (cobalamin) may give discordant results from the patient's clinical status.
Patient evaluation: immunoassay
Situations:
(1) very high vitamin B12 inconsistent with intake
(2) normal value inconsistent with clinical deficiency
Reasons for a false-positive result may include:
(1) anti-intrinsic factor autoantibodies
(2) heterophile antibody
(3) human antibody to animal antibody reagent
(4) rheumatoid factor
(5) paraprotein
LC-MS/MS following solid-phase extraction can be used to determine the true vitamin B12 status. This can be used if heterophile antibody blocking or dilution fails to correct the problem.
To read more or access our algorithms and calculators, please log in or register.
