Human serum vitamin B12 assay methods--a review

Area of Science:

• Clinical Chemistry
• Biochemical Diagnostics

Background:

• Reliable human serum vitamin B12 assays are critical for diagnosing pernicious anemia (PA).
• Existing serum B12 assays, particularly commercial kits, face significant controversies and criticisms regarding their accuracy and precision.
• A validated reference method for quantifying serum vitamin B12 with high accuracy, precision, and rapidity is currently unavailable.

Purpose of the Study:

• To review the limitations of current human serum vitamin B12 quantitation methods.
• To establish a foundation for developing a new, accurate B12 reference method in the laboratory.
• To highlight the clinical need for improved vitamin B12 diagnostic tools.

Main Methods:

• Literature review of existing vitamin B12 quantitation techniques.
• Analysis of microbiological, radioisotopic, high-performance liquid chromatography (HPLC), and radioimmunoassay (RIA) methods.
• Critical evaluation of assay accuracy, precision, and rapidity.

Main Results:

• No reported reference method for serum vitamin B12 quantitation meets the required standards for accuracy, precision, and speed.
• Widespread debate and criticism surround the reliability of current human serum B12 assays.
• Identified limitations across microbiological, radioisotopic, HPLC, and RIA techniques.

Conclusions:

• Current serum vitamin B12 assays are insufficient for reliable pernicious anemia diagnosis.
• There is a pressing need for the development of a new, robust reference method for serum B12 measurement.
• This review provides critical insights into existing method limitations, guiding future reference method development.