Active B12 (holotranscobalamin): what your result means.

The biologically active form of B12; more accurate than total B12 for deficiency. Active B12 (holotranscobalamin) is measured by blood test as part of the Nutritional panel in the HodieLabs Health Blueprint.

Why Active B12 (holotranscobalamin) matters

Optional refinement; include only if available/cost-effective. Interpret using the reporting lab’s reference interval and clinical context; trend over time is often more informative than a single value.

Associated risks when out of range: Low active B12 is the earliest marker of functional B12 deficiency, more sensitive than serum B12. Functional B12 deficiency can cause irreversible neurological damage if untreated.

Evidence basis

The HodieLabs Evidence-Based Clinical Library classifies Active B12 (holotranscobalamin) as an strong evidence-tier biomarker. Its reference ranges come from a published authority standard rather than from observational optimisation targets. The standard used here is RCPA Australian pathology and B12 diagnostic consensus; holotranscobalamin >50 pmol/L adequate, <25 deficient. Where relevant clinical outcomes are noted on this page, they reflect the guideline literature referenced below.

Evidence-based reference ranges

The HodieLabs Evidence-Based Clinical Library interprets Active B12 (holotranscobalamin) against published clinical authority standards, never arbitrary "optimal" ranges. Measured in pmol/L:

Band	Range (pmol/L)
Optimal	>50 pmol/L
Borderline	25–50 pmol/L
Low	<25 pmol/L

Clinical interpretation

• Optional refinement; include only if available/cost-effective.
• Interpret using the reporting lab’s reference interval and clinical context; trend over time is often more informative than a single value.

What improves it: the evidence-based levers

• Active B12 should be first-line for B12 assessment, more specific than total B12
• If low, supplementation with methylcobalamin or hydroxocobalamin; investigate cause (pernicious anaemia, PPI use)

Recommended testing frequency: Annual, as part of a comprehensive panel. Single markers are always interpreted in context.

How Active B12 (holotranscobalamin) testing works at HodieLabs

Active B12 (holotranscobalamin) is measured in every Health Blueprint at our Melbourne Preventative Health & Longevity Clinic, interpreted by a doctor against the guideline-cited ranges above and tracked over time through your HodieLabs membership.

References

1. RCPA Australian pathology and B12 diagnostic consensus; holotranscobalamin >50 pmol/L adequate, <25 deficient.

This page is general information from the HodieLabs Evidence-Based Clinical Library, not medical advice. Speak with your GP about what testing and care is appropriate for you.