Vitamin B2 Test
Vitamin B2 Test can be requested without a referral, and this overview covers what to expect. A Vitamin B2 test measures the amount of riboflavin (vitamin B2) in your blood. It is usually ordered when a doctor suspects a deficiency, which can cause symptoms like fatigue, cracked lips, or sore throat, or to monitor certain health conditions.
- Sample type
- blood
- Category
- Vitamin & Mineral
- Turnaround
- 1-3 business days
- Price
- $120
- Referral
- Not required
A Vitamin B2 test measures the amount of riboflavin (vitamin B2) in your blood. It is usually ordered when a doctor suspects a deficiency, which can cause symptoms like fatigue, cracked lips, or sore throat, or to monitor certain health conditions.
What it measures
- Vitamin B2 (riboflavin) — The main nutrient being measured.
- Erythrocyte glutathione reductase activity — An enzyme test that reflects how well B2 is working in your red blood cells.
- Erythrocyte glutathione reductase activation coefficient (EGRac) — A calculated ratio that helps assess B2 status more accurately.
Who it is for
Doctors typically order this test for people with signs of vitamin deficiency, poor diet, malabsorption conditions, or those taking certain medications that affect B2 levels.
Preparation
No fasting is usually required. Tell your doctor about all medications and supplements you take, as some can affect the results.
Results and what they mean
Results are reported as a number or range for each marker, and your doctor will interpret them based on your health history and other tests. A low result may suggest deficiency, but only a clinician can determine what it means for you. This is general information, not medical advice.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the vitamin b2 test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for this test?
No, fasting is not typically needed.
What can cause low vitamin B2?
Poor diet, alcohol use, certain medications, and conditions that affect nutrient absorption can lead to low levels.
How long until I get results?
Results are usually available within 1 to 3 business days.
Can I take my vitamins before the test?
Ask your doctor. Some supplements may affect the results, so they may ask you to stop them temporarily.