The objective of THE SERUM B12 EXPERIMENT PART A was to investigate the performance of tests for vitamin B12 deficiency, as deficiency developed, after ceasing B12 treatment.

These are the tests that I compared as markers of vitamin B12 deficiency:

• Total serum B12
• Methylmalonic acid
• Total homocysteine
• Full Blood Examination

When it became clear that there were serious pathology laboratory errors, the experiment was expanded to include investigation of the quality of these assays performed by the laboratories:

• Methylmalonic acid (MMA)
• Total homocysteine (tHCY)

The additional investigations are described in THE METHYLMALONIC ACID INVESTIGATION and in THE HOMOCYSTEINE INVESTIGATION.