Vitamin B12 + Folat

A two-marker panel measuring serum vitamin B12 (cobalamin) and folate (vitamin B9). Both vitamins are essential for DNA synthesis, red blood cell formation, and neurological function. Deficiency in either can cause megaloblastic anaemia, cognitive impairment, and peripheral neuropathy. This combination is particularly relevant for vegetarians, vegans, older adults, and patients on metformin or proton pump inhibitors.

Vitamin B12 and folate work in tandem within the methylation cycle — a metabolic pathway that underpins DNA repair, neurotransmitter synthesis, and homocysteine clearance. When either vitamin is insufficient, the cycle stalls, leading to elevated homocysteine (an independent cardiovascular risk factor), impaired red blood cell maturation, and progressive neurological damage that may be irreversible if caught late. B12 deficiency develops insidiously because the liver stores enough to mask inadequate intake for two to five years. By the time symptoms appear — numbness, balance problems, cognitive fog, mood changes — significant nerve damage may already exist. Groups at elevated risk include vegans and strict vegetarians (B12 is found almost exclusively in animal products), adults over 60 (reduced intrinsic factor and gastric acid production), patients on proton pump inhibitors (impaired B12 absorption), and those taking metformin (which interferes with B12 uptake in the ileum). Folate deficiency presents more rapidly, typically within months of inadequate intake, and is especially critical during early pregnancy when it dramatically increases the risk of neural tube defects. At SYNLAB München Zentrum, both markers are measured from a single venous blood draw. No fasting is required. Results are typically available within one to two working days.