Experiencing brain fog, memory issues, or unexplained fatigue and wondering if you're getting the active form of vitamin B12 your nerves and brain need to function optimally?
The Active Vitamin B12 Blood Test, also called the HoloTC Test, measures the form of B12 that your body can actually use. This test may help detect early deficiency that total B12 tests can miss, supporting the prevention of anaemia, fatigue, and nerve-related problems.
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So how does it work?
Bloody Good is a single portal for ordering, tracking, and reviewing on-demand health testing. Get started with three simple steps:
1
Book your test
Choose the testing that suits your goals. After ordering, you will receive your referral by email.
2
Collect your samples
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3
View your results
View your lab results and receive a personalised review from the secure Bloody Good platform.
The Active Vitamin B12 Blood Test, also called the HoloTC Test, measures the form of B12 that your body can actually use. This test may help detect early deficiency that total B12 tests can miss, supporting the prevention of anaemia, fatigue, and nerve-related problems.
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.
You may benefit from the Active Vitamin B12 (HoloTC) Blood Test
Essential for individuals with neurological symptoms, dietary restrictions, absorption problems, or anyone needing comprehensive active B12 and neurological assessment.
Feeling tired all the time
Extreme fatigue that doesn't improve with rest
Difficulty concentrating on tasks
Mind feeling foggy or cloudy
Problems with short-term memory
Tingling in hands or fingers
Numbness in feet or toes
Feeling sad or down most of the time
Lack of motivation to do usual activities
Difficulty finding the right words
Getting lost in familiar places
How to prepare
No special preparation required. Inform healthcare provider of B12 supplements, dietary habits, and any factors that might affect B12 levels or interpretation.
Understanding results
Results show active B12 levels compared to normal ranges. Low levels may indicate B12 deficiency requiring supplementation and investigation of underlying causes.
After the test
Address B12 deficiency through appropriate supplementation (oral or injection), dietary modifications, and treatment of underlying absorption problems. Work with neurologists for complex cases.
Frequently Asked Questions
Active B12 (holotranscobalamin) is the biologically available form of vitamin B12 that cells can actually use for nerve function and DNA synthesis.
Active B12 measures only the usable form, while total B12 includes inactive forms, making active B12 a more accurate indicator of deficiency.
Symptoms may include numbness, tingling, memory problems, fatigue, depression, balance problems, and in severe cases, irreversible nerve damage.
Causes include inadequate dietary intake (especially in vegetarians), pernicious anemia, gastrointestinal disorders, and certain medications affecting absorption.
Treatment typically includes B12 supplements (oral or injection), dietary modifications, and addressing underlying absorption problems.
Yes, severe B12 deficiency can cause irreversible neurological damage, making early detection and treatment crucial.
Reviewed by Dr. Vu Tran Bloody Good’s Chief Medical Officer
Bloody Good is a single portal for ordering, tracking, and reviewing on-demand health testing.
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Find answers to common questions about our products and services.
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.
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