Premium Nahrungsergänzungsmittel | artgerecht

Holotranscobalamin – Active B12 as a Deficiency Marker

Holotranscobalamin is the biologically active form of vitamin B12 in the blood and is considered the earliest marker of vitamin B12 deficiency.

Regular tips about health Regular tips about health

Things worth knowing about "Holotranscobalamin"

Holotranscobalamin is the biologically active form of vitamin B12 in the blood and is considered the earliest marker of vitamin B12 deficiency.

What is Holotranscobalamin?

Holotranscobalamin (also known as HoloTC or Active B12) is the biologically active fraction of vitamin B12 (cobalamin) in human blood. It consists of vitamin B12 bound to the transport protein Transcobalamin II. Only this bound form can be taken up and used by the body's cells. Holotranscobalamin represents approximately 10–30% of the total vitamin B12 in the blood, but it is the only fraction that is actually available to cells for metabolic use.

Biological Functions

Vitamin B12 performs numerous vital functions in the human body. Since only the holotranscobalamin fraction can be taken up by cells, its blood level directly reflects the available B12 supply at the cellular level. Key functions of vitamin B12 include:

Formation and maturation of red blood cells (haematopoiesis)
Synthesis and repair of DNA
Function and protection of the nervous system (myelin synthesis)
Breakdown of hom*ocysteine in cooperation with folate and vitamin B6
Involvement in cellular energy metabolism

Holotranscobalamin as a Biomarker

In clinical diagnostics, holotranscobalamin is regarded as the earliest and most specific marker of vitamin B12 deficiency. Compared to measuring total vitamin B12 in serum, HoloTC has the advantage of declining at a very early stage of deficiency – before classic signs such as blood changes or neurological symptoms appear.

Advantages Over Total B12 Measurement

HoloTC reflects the fraction of B12 that is actually available to cells
Earlier detection of deficiency before clinical symptoms develop
Higher specificity for functional B12 deficiency
Less influenced by liver or kidney disease compared to total B12

Reference Values and Interpretation

Reference ranges may vary slightly between laboratories. General guidelines are:

Below 35 pmol/l: Indicates vitamin B12 deficiency
35–50 pmol/l: Grey zone, repeat testing recommended
Above 50 pmol/l: Adequate B12 status likely

When deficiency is suspected, HoloTC should ideally be combined with additional markers such as methylmalonic acid (MMA) and hom*ocysteine to confirm a functional deficiency.

Risk Groups for B12 Deficiency

Certain groups of people are at increased risk of low holotranscobalamin levels:

Vegans and vegetarians: Vitamin B12 is found almost exclusively in animal-derived foods
Older adults: Reduced gastric production of intrinsic factor and stomach acid
Patients with gastrointestinal conditions (e.g., Crohn's disease, coeliac disease, gastric resection)
Pregnant and breastfeeding women: Increased nutritional requirements
Patients on metformin or proton pump inhibitor therapy

Diagnosis and Testing

Holotranscobalamin is measured from a simple blood sample (serum). The test is available at most medical laboratories and can be ordered by a physician. Measurement is typically performed using automated immunoassay methods.

Treatment of Low Holotranscobalamin

When a vitamin B12 deficiency is confirmed, several treatment options are available:

High-dose oral B12 supplements: Often sufficient for mild to moderate deficiency
Intramuscular injections of hydroxocobalamin or cyanocobalamin: Used for severe deficiency or absorption disorders
Dietary adjustments: Increasing intake of B12-rich foods (meat, fish, dairy products, eggs)

References

Herrmann W, Obeid R. - Causes and early diagnosis of vitamin B12 deficiency. Deutsches Aerzteblatt International, 2008; 105(40): 680–685.
Nexo E, Hoffmann-Lücke E. - Holotranscobalamin, a marker of vitamin B12 status: analytical aspects and clinical utility. American Journal of Clinical Nutrition, 2011; 94(1): 359S–365S.
World Health Organization (WHO) - Vitamin and Mineral Requirements in Human Nutrition, 2nd edition, Geneva, 2004.

Building Blocks for a Healthy Life

As an integrated manufacturer, we develop & produce evidence-based, patented, and non-patented formulations. We work exclusively with plant and natural extracts according to the strictest purity & quality standards.
The combination of science & modern technology with the laws of nature creates solutions consistently tailored to humans – for the highest good: health.