1. 1. Order Your Tests

    Browse from hundreds of tests and select the ones you want.

  2. 2. Visit a Lab

    Visit a lab near you at your convenience; no appointment time necessary.

  3. 3. Get Your Results

    Physician-reviewed lab results are available online within 24-72 hours.

Vitamin B3 Test (Niacin Test)

This Vitamin B3 Test, sometimes referred to as a niacin test, is used to measure the amount of vitamin b3 (niacin) in the blood.

Order Test
Test Preparation:
Testing Method:
Blood draw

This Vitamin B3 Test, sometimes referred to as a niacin test, is used to measure the amount of vitamin b3 (niacin) in the blood. Vitamin B3 (or niacin) is fundamental in converting carbohydrates to glucose and metabolizing fats and proteins. Meat, fish, and carbohydrates are excellent sources of vitamin B3. Those with a slight vitamin B3 deficiency are prone to fatigue, canker sores, vomiting, and/or changes in mood while more serious symptoms can include rash, tongue swelling, and even disorientation or memory loss. But, Priority Lab Testing’s Vitamin B3 Test can determine such a deficiency for certain.

How Our Vitamin B3 (Niacin) Test Works

For our Vitamin B3 (Niacin) test, simply place your order online and stop by one of our 4000+ nationwide testing facilities at your convenience (no appointments). A member of the center’s staff will collect a small blood sample via the skin prick method, at which point your part of the process is done.

The sample collection itself takes only a few minutes, and most patients are in and out and about their day in under half an hour. From there, your sample will be processed in a CLIA-certified laboratory, and in as little as 24-72 hours, you’ll have full results regarding your Vitamin B3 (Niacin) status.

Common Vitamin B3 (Niacin) Deficiency Symptoms

Vitamin B3, also known as Niacin, is one of 8 B vitamins. Vitamin B3 is a water-soluble vitamin that plays a number of essential roles in the body. Niacin helps manufacture and repair DNA, keeps the nervous system working properly, metabolizes fats and proteins, and exerts antioxidant effects.

Naturally occurring in foods such as eggs, fish, poultry, meat, fruits, and vegetables, Niacin primarily contains two chemicals, Nicotinic Acid and Nicotinamide. If you have a balanced diet, you’ll have healthy niacin levels naturally.

Niacin deficiency typically occurs when a person does not get sufficient vitamin B3 in their diet. Common symptoms of Niacin deficiency include:

  • Vomiting and diarrhea
  • Fatigue
  • Indigestion
  • Headache
  • A bright red tongue
  • Swollen mouth
  • Depression
  • Memory loss and disorientation

Symptoms of Niacin deficiency may vary from one person to the next. If you are experiencing any combination of the above symptoms, we recommend that you take our Vitamin B3 (Niacin) test. Your doctor may also order the same.

How to Interpret Your Results

Our vitamin B3 (Niacin) measures the amounts of Niacin in the bloodstream to determine Vitamin B3 (Niacin) deficiencies. Niacin is primarily made up of Nicotinic Acid and Nicotinamide. Our vitamin B3 (Niacin) test evaluates the levels of both components to determine the root cause of your symptoms.

The results of your Niacin test will be delivered via our secure online portal for maximum convenience. It’s imperative that you interpret the results of your Vitamin B3 (Niacin) carefully and understand what the outcome means for your health. The results of your Vitamin B3 (Niacin) test may seem a little puzzling at first glance.

But there’s no need to worry; we do our best to ensure that interpreting the results is as straightforward as possible. When reviewing your results, you’ll see a test results chart showing the level of Vitamin B3 (Niacin) in your body. Abnormal values, anything above or below the normal range, will be flagged. 

What Are the Possible Complications of Vitamin B3 (Niacin) Deficiency?

Severe Niacin deficiency, a condition known as Pellagra, affects the whole body and is life-threatening. Pellagra is a systemic disease associated with a dark, scaly rash that appears symmetrically in areas exposed to sunlight. Other serious symptoms include dermatitis, diarrhoea, dementia, and, ultimately, death.


  • A blood test is one of the most sensitive and reliable measures of Niacin status. A blood test can check for vitamin B3 or Niacin levels in your blood and identify any potential deficiencies.

  • Our Vitamin B3 (Niacin) test measures the amount of the vitamin in your blood. Your doctor may order a Niacin test if you are showing symptoms of Niacin deficiency or taking Niacin supplements to help monitor your levels.

  • Niacin deficiency can lead to a wide range of symptoms. Severe vitamin B3 deficiency — often associated with malnutrition — results in a life-threatening condition known as Pellagra.