Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test
Active Vitamin B12 (HoloTC) Blood Test

Over 250k Biomarkers Tested

Active Vitamin B12 (HoloTC) Blood Test

$73.00 AUD

Got a borderline B12 result and want to know whether it's actually a problem before doing anything about it?

Measures holotranscobalamin (HoloTC), the metabolically active fraction of vitamin B12. More sensitive than a standard B12 test for detecting early deficiency, as HoloTC declines before total B12 falls below the reference range.

Collection Location
Specimen Type

You will be emailed a referral to take to your local collection centre. If you ever have any questions, we're here to help.

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Private health tests

How It Works

Getting your health measured shouldn't be hard! We're here to help you every step of the way.

1
Order a test

Order a test

Order the private test that suits you and your goals. After ordering, you will receive your referral by email.

2
Collect the sample

Collect the sample

Attend one of our 4000+ partner collection centres throughout Australia. Search locations.

3
Receive your results

Receive your results

View all your lab results in your secure health dashboard. Easy!

Overview

Think of vitamin B12 as your body's master electrician and repair crew all rolled into one. This essential vitamin keeps your nerves firing properly, helps build healthy red blood cells, and ensures your DNA can repair itself effectively. The Active Vitamin B12 test specifically measures the form of B12 that your cells can actually use—not just what's floating around in your bloodstream. It's like checking whether you have working batteries in your flashlight, not just batteries sitting in a drawer.

This test is particularly valuable because it can catch B12 deficiency early, before you develop serious symptoms like nerve damage, severe fatigue, or cognitive problems. If you're experiencing unexplained numbness, memory issues, or persistent tiredness—or if you follow a vegetarian diet, have digestive issues, or take certain medications—this test can reveal whether low B12 is the culprit. Since B12 deficiency can cause irreversible nerve damage if left untreated, getting an accurate picture of your active B12 levels helps ensure your body's electrical system stays running smoothly for years to come.

Symptoms

To measure the biologically active fraction of vitamin B12 (holotranscobalamin) for earlier detection of B12 deficiency, particularly when total B12 results are inconclusive or borderline.

Questions

  • Holotranscobalamin is the portion of vitamin B12 in your blood that is bound to a protein called transcobalamin II, which carries B12 into cells where it can be used. Only about 20–30% of total serum B12 is in this active form. The rest is bound to proteins that don't deliver B12 to cells. Measuring HoloTC tells you how much B12 is actually available for your body to use.
  • The standard B12 test measures total serum B12, including both active (HoloTC) and inactive fractions. Total B12 can appear within the normal range even when functional B12 availability is low, because the inactive fraction props up the total. HoloTC falls earlier in the process of B12 depletion, making it a more sensitive indicator of early deficiency.
  • This test is worth considering if you have a borderline or low-normal total B12 result and want more certainty, if you have symptoms consistent with B12 deficiency despite a normal total B12, or if you're in an ongoing high-risk group (vegans, vegetarians, long-term metformin users, people with absorption conditions) and want sensitive monitoring.
  • HoloTC can be used to track whether B12 levels are responding to supplementation or injections. It rises relatively quickly once B12 status improves. Discuss the best monitoring approach with your practitioner.
  • It depends on context. If you haven't had a B12 test before, running both provides the most complete picture. If you already have a recent total B12 result and just want clarity on whether your borderline result is meaningful, the Active B12 (HoloTC) test alone can help answer that question.

Dr. Vu Tran
Bloody Good’s Chief Medical Officer

Biomarker Tested

How to prepare

No specific fasting required. You can eat and drink normally. If you take B12 supplements or have recently had a B12 injection, note this as it can affect your result. A recent injection in particular can produce a temporarily elevated reading.

After the test

If HoloTC is low, speak with a GP about the cause and appropriate treatment. For dietary deficiency (common in vegans and vegetarians), oral B12 supplementation is often effective. For malabsorption conditions or pernicious anaemia, B12 injections are typically the preferred approach. Your practitioner can recommend the right option based on your situation.

Your test results will be available in your private dashboard. If there are any urgent issues, we'll let you know so you can follow up with your health professional.

Understanding results

HoloTC is reported in pmol/L alongside a reference range. Lower HoloTC values indicate less biologically available B12 and are a stronger early marker of deficiency than total serum B12. A practitioner can interpret the result in the context of any symptoms and your risk factors. If HoloTC is low but total B12 appears normal, this is a meaningful finding worth discussing with a GP.

Testimonials

What Our Customers Say

4.9
Average Rating
5,500+ Customers Tested
250,000+ Individual Biomarkers
A
Adam O. ACT

Simple health checks in my control

I didn't know that private blood tests were an option. Tried this platform as the packages suited what I wanted for a good price. Easy to follow instructions, and super quick results. Platform provides more information than my gp's ever have on the tests and what the results meant. Would like more clinics to be able to test at (specifically Capital Pathology) but there is a decent network. Will continue to use.

The Performance Check
W
Wayne S. NSW

Bloody Good

This is a great service, very helpful support, cheaper than going to the doctor for a blood test

Vitamin D (25-OH)
C
Christopher N. NSW

Quick access to blood tests

BLOODY GOOD is a very efficient route to access blood testing for a visitor outside the Australian health system. It is quick with the necessary referral and documentation, and quick with results. Thank you

Full Blood Count (FBC) Blood Test
R
Rebecca Y NSW

Great Service!

Fantastic service to deal with, I love the extra explanations for all the tests.

Glycated Haemoglobin (HbA1c)
O
Olga B. New South Wales

Convenient

Getting a referral was easy. Laverty pathology accepted it. Bloody Good offers an affordable and convenient way to check essential blood markers.

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Lukas C. NSW

Quick, easy, hassle free

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Testosterone Free/Total + SHBG
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ABDUL S. QLD

Amazingly quick and efficient

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Andre D. QLD

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Frequently bought together

Frequently Asked Questions

Most collection centres accept walk-ins. Some may require a booking - check details when you click on your chosen location.

If your test needs fasting, we’ll include that in your instructions after you order. Fasting usually means no food for 8–12 hours, but water is fine.

Just your pathology referral form (we email it to you)

Of course. Just maybe don’t bring the friend who faints at the sight of blood.

They’re the highly trained professionals who take your blood sample - with a steady hand and a sharp needle. They love blood, but don’t worry… they’re not vampires. Just legends who make blood tests quick, clean, and (almost) painless.

Some of our tests include Urine, Stool, Saliva and more. Each test will have a clear description on what sample you will need to give and instructions on how.