Home / All Tests / Active Vitamin B12 (Holo-TC) Test
Rating of Homed-IQ Homed-IQ on TrustPilot

Active Vitamin B12 (Holo-TC) Test

39,00 Free Shipping to

Are you dealing with symptoms such as fatigue, muscle weakness and/or memory and mood problems? Vitamin B12 is an essential nutrient that is vital for brain function, nerve health, healthy red blood cell formation, and DNA creation. Active vitamin B12 (Holo-TC) represents the amount of vitamin B12 readily usable by the body. This measurement offers a more accurate view of vitamin B12 status, as total B12 levels may appear to be normal while the quantity that is usable by the body is still low. Use this self-test to check your active vitamin B12 levels quickly and easily from home.

Test method: Finger prick dried blood spot test

What do we test for?

Active Vitamin B12 (Holotranscobalamin)
Instructional video
  • Buy 2 or more products and get 5% off your order
  • Ordered before 19:00, shipped today
  • Analyzed in ISO-certified laboratory
  • Test results often available within 1 business day after reaching laboratory

39,00 Free Shipping to

About the test
Summary of Biomarkers
Causes of Vitamin B12 Deficiency
About the test

What is an active vitamin B12 test?

An active vitamin B12 test measures the amount of vitamin B12 available for use by the body, also known as Holotranscobalamin or Holo-TC, in the blood. Unlike standard B12 tests that evaluate total vitamin B12 levels, this test specifically assesses the fraction of vitamin B12 that is readily available for use in the body’s cells. This can provide a more accurate indicator of vitamin B12 status, especially in cases where someone may have adequate total B12 levels but a deficiency in the active form that the body can utilize. It is particularly beneficial for diagnosing B12 deficiency in its early stages and can be used to monitor the effectiveness of B12 supplementation or to investigate symptoms related to anemia or nerve function.

What’s in the test kit?

This test kit contains instructions for use, lancets for collecting a few drops of blood, a dried blood spot collection card, alcohol wipes, band-aids, a protective transport bag and a return envelope to send your sample to our certified laboratory.

What is the Homed-IQ testing process like?

Homed-IQ’s vitamin tests come with everything you need to successfully take a dried blood spot sample at home. Simply activate your test and follow the provided instructions to successfully collect the sample. Next, package and send the sample to our certified laboratory using the prepaid shipping label, free of charge. The results will be available within a few days.


What are the most common symptoms of vitamin B12 deficiency?

Common symptoms of vitamin B12 deficiency are:

  • Fatigue and weakness
  • Lightheadedness
  • Heart palpitations and shortness of breath
  • Pale skin
  • A smooth tongue
  • Constipation, diarrhea, loss of appetite, or gas
  • Vision problems
  • Mental health problems like depression, memory loss, or behavioral changes
  • Nerve problems like numbness, tingling, muscle weakness, and problems walking
Summary of Biomarkers

Active Vitamin B12 (Holotranscobalamin)

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in various bodily processes. It is essential for the production of red blood cells, DNA synthesis, and proper functioning of the nervous system. The human body cannot produce vitamin B12 on its own, so it must be obtained from dietary sources or supplements.

There are two forms of vitamin B12 in the body: active B12 and inactive B12, both of which comprise Total B12. The key difference between these two forms is that active B12 is the form utilized by the body. The active form of vitamin B12 is known as Holotranscobalamin, or Holo-TC.

Vitamin B12 is naturally found in animal products such as meat, fish, eggs, and dairy. People who do not eat animal products may be at risk of vitamin B12 deficiency, as plant-based foods generally do not contain sufficient amounts of this vitamin. A vitamin B12 deficiency can lead to anemia, fatigue, neurological problems, and other health issues. Common symptoms of B12 deficiency include weakness, tingling or numbness in the hands and feet, memory problems, and difficulty with balance.

Why test active B12 instead of complete B12?

Testing active B12 (Holotranscobalamin or Holo-TC) instead of total B12 offers a more accurate and clinically relevant assessment of vitamin B12 status in the body. While a total B12 test includes both active and inactive forms of the vitamin, it’s the active B12 that is readily available for cellular use and essential for important functions like red blood cell formation and neurological health. In some cases, total B12 levels may appear normal even when there’s a deficiency in the active form, leading to undetected deficiencies. By specifically measuring active B12, deficiencies and their associated symptoms can be more accurately diagnosed and treated.

Causes of Vitamin B12 Deficiency

What are the most common causes of vitamin B12 deficiency?

  • Lack of B12 in diet: Vitamin B12 cannot be produced by our bodies, meaning it needs to be obtained through food or drinks. Your body stores vitamin B12 for future use, and it can take years before your body uses up its B12 reserves. Vitamin B12 is almost exclusively found in animal products, so people who follow a vegan or vegetarian diet should include foods fortified with vitamin B12 in their diet.
  • Pernicious anemia: This rare autoimmune condition is one of the most common causes of a B12 deficiency. During this disease, the immune system attacks the cells in the stomach that produce intrinsic factor, a protein needed for your body to absorb B12. As your body needs vitamin B12 to make red blood cells, anemia occurs.
  • Conditions affecting the stomach or intestines: Crohn’s disease, gastritis, Celiac disease and other stomach or intestinal diseases can affect B12 absorption.
  • Certain medications: some medicines can reduce the amount of vitamin B12 in your body or make existing deficiencies worse. Your doctor should inform you of medications that could affect your vitamin B12 levels.

What do the results of this test mean?

Active Vitamin B12 Deficiency

A vitamin B12 level below 40.2 pmol/L indicates an active vitamin B12 (Holo-TC) deficiency. This can be caused by different factors. If your vitamin B12 is low, see your GP. While some people can take supplements or make changes to their diet to replenish their B12 levels, others may require vitamin B12 injections or have an underlying condition that is causing low B12.

To boost your vitamin B12 through diet, eat more foods that contain it. These foods include:

  • Fish and shellfish
  • Beef, chicken, and liver
  • Eggs
  • Fortified breakfast cereals
  • Low-fat milk, yogurt, and cheese


Sufficient Active Vitamin B12

An active vitamin B12 (Holo-TC) level above 40.2 pmol/L is sufficient.


How soon will I receive the results of this at-home vitamin test?

Once you have taken your blood sample and sent it to our medical partner laboratory, it should take a few working days to receive your test result. As soon as your test kit arrives at the laboratory you will receive a notification by email. Once your test result is ready, you will receive a text message and an email with a link to your result. Homed-IQ aims to keep you well informed throughout the testing process and provide a seamless testing experience.

Frequently asked questions

How reliable is this vitamin B12 test?

The sensitivity and specificity for this blood test is almost 100%. Sensitivity is the ability of a test to correctly identify test users with a disease. Specificity is the ability of a test to correctly identify test users without the disease.

Has this vitamin B12 test been reviewed by a doctor?

All of Homed-IQ’s self-sampling tests are scientifically certified and validated by the laboratory for home use. This means the tests have been checked by our lab to ensure the results of finger prick samples taken at home are as accurate as samples taken in a blood testing center or doctor’s office. It is only legal to sell validated medical tests. Each sample is processed in a laboratory that is ISO15189 certified, which allows us to guarantee the reliability of the tests.

Is this vitamin test also useful for vegetarians and vegans?

Yes. When you eat plant-based, it is advisable to keep a close eye on your vitamin levels. This is especially true for vitamin B12, as it is a common vitamin deficiency among vegetarians and vegans. 

How do you know if you are deficient in vitamin B12?

Unlike other deficiencies like vitamin D, a lack of vitamin B12 usually causes noticeable symptoms. Untreated, a lack of vitamin B12 can be dangerous and impact the entire body. However, early symptoms could be confused for other conditions or simply tiredness. The only definitive way to know if you are deficient in vitamin B12 is through a test. A blood test is the most common way to check vitamin B12, but it is also possible to use a urine test.

How much vitamin B12 do you need daily?

The recommended daily vitamin B12 intake for adults is 2.8 micrograms a day.

How long will it take for my vitamin B12 levels to return to normal?

Once you begin treating your vitamin B12 deficiency, it can take six to 12 months for levels to return to normal. You may not see any improvement in the first few months of treatment, but symptoms should gradually decrease.

What are the risks of a vitamin B12 deficiency?

Severe vitamin B12 deficiency can cause neurological problems, such as vision loss, memory loss, and reduced physical coordination. Furthermore, low B12 can cause anemia and its associated complications.

Can I also test the level of other vitamins or minerals with Homed-IQ?

This test only measures vitamin B12 levels in blood. If you would also like to test for other vitamins or minerals, we recommend Homed-IQ’s Vitamin Deficiency Test. In addition to vitamin B12, this test also measures folic acid and vitamin D levels in the blood. If you would like to gain a more complete picture of your health, consider our Preventive Health Screening.

Will my health insurer reimburse this vitamin test?

We currently do not have any agreements with health insurers. At Homed-IQ we therefore keep our tests as affordable as possible to give everyone the opportunity to get a better understanding of their health.

What is the difference between active and inactive vitamin B12?

Active vitamin B12, also known as Holotranscobalamin or Holo-TC, refers to the portion of vitamin B12 that is readily available for use by the cells and body tissues. This form is crucial for key bodily functions, including nerve health, red blood cell production, and DNA synthesis. Total vitamin B12, in contrast, includes both the active and the inactive forms of the vitamin. The inactive portion, while contributing to the overall B12 level, is not immediately usable by the body. Measuring total B12 can sometimes mask deficiencies in active B12, as the total level might appear adequate despite a shortage in the active form. As such, measuring active B12 can provide a more accurate reflection of the vitamin's functional status in the body.

How does it work?

Order your test
After you have placed the order, your test kit will be delivered within a few days in discreet packaging.
Activate and take your sample

After creating an account and activating your test online, collect the test sample and return it to the lab using the prepaid shipping label. Homed-IQ tests can be placed in a regular mailbox.

Receive your test result

A certified laboratory will analyze your test. When ready, your results will be published to your account, including a PDF laboratory report that can be brought to your GP for follow-up care.

Related products

You may also like…

4.7 out of 5 stars on Trustpilot

Read the experiences of our customers

See all reviews