Diagnostic Value of Elevated and Significantely Elevated Levels of Vitamin B12

Vitamin B12 (B12) or cobalamin (Cbl) is involved in many relevant biochemical processes in the human organism – methylation, DNA synthesis, myelin synthesis, and the metabolism of methylmalonic acid. Although B12 has an indirect effect on some of these processes, vitamin deficiency can cause health problems – megaloblastic and pernicious anaemia, neurological disorders, and increase the risk of cardiovascular disease. B12 deficiency is quite rare and is associated with strict veganism and malabsorption of the vitamin in the digestive system. In clinical laboratory practice, patients with elevated levels of total B12 in the blood are often encountered. The reasons for the B12 level increment are often associated with the additional intake of the vitamin in the form of a dietary supplement, as well as the result of parenteral use. However, there is also a large group of patients in whom elevated and significantly elevated levels of total B12 are associated with pathology of the kidneys, liver, and myeloproliferative diseases. This work investigated whether elevated and significantly elevated B12 levels can serve as a marker of various pathologies. This study reviews the causes of elevated B12 levels. Reference intervals (RIs) for total B12, typical of the population of Latvia as a whole, were determined, from the results of laboratory analyses of patients accumulated over several years. RIs were determined for the general population and for different age groups. It is recommended that the definition of the B12 RI be reviewed separately for children. Based on a large amount of accumulated patient data, it was concluded that elevated vitamin values are associated with liver and kidney pathologies. Significantly elevated levels of total B12 are closely correlated with various myeloproliferative disorders, especially with chronic myeloid leukaemia. The values of increased total B12 intervals and their relationship with these pathologies were determined. It was concluded that elevated and significantly elevated levels of total B12 can be used as an indirect indicator in the diagnosis of hepatic, renal and myeloproliferative diseases.