Can Vitamin B12 Cause a False Positive on Drug or Medical Tests?

October 8, 2025 •

3 min read

According to Boston Medical Center research, drug tests produce false positive results in 5% to 10% of cases. While pure vitamin B12 itself is generally not the direct cause, a false positive is a valid concern for individuals taking certain supplements containing B12, as other ingredients can interfere with common drug and medical tests.

Quick Summary

This article explains how certain B-complex vitamins, including potential contaminants in some B12 supplements, can lead to false positive results on drug screenings and standard medical tests. It outlines specific scenarios and provides guidance on how to avoid inaccurate readings.

Key Points

Pure Vitamin B12 Is Not the Cause: Isolated vitamin B12 does not typically cause a false positive on standard drug or medical tests.
B-Complex Contamination Risk: The danger lies in B-complex supplements containing riboflavin sourced from hemp seed oil, which can trigger a false positive for THC.
Biotin Interferes with Lab Tests: Biotin (vitamin B7), commonly included in B12 supplements, is known to significantly interfere with specific medical tests, such as those for thyroid and heart conditions.
Screening vs. Confirmatory Tests: Initial immunoassay screenings can produce false positives due to cross-reactivity, while specific confirmatory tests (like GC-MS) are highly accurate.
Inform and Disclose: The most effective way to prevent and manage a false positive is to inform testing personnel of all supplements and medications you are taking.
FDA Warns Against Biotin: The FDA has issued a safety warning about biotin interference with lab tests, especially cardiac troponin levels, which could lead to misdiagnosis.

Drug Tests: B-Complex and Contamination

Pure vitamin B12 is not known to cause false positives on standard urine drug tests. However, some B-complex supplements containing B12 can pose a risk due to other ingredients.

Riboflavin (B2) and Hemp Oil

Riboflavin (vitamin B2) can cause false positives for marijuana if derived from hemp seed oil, which may contain trace THC. This is particularly relevant for those subject to drug testing.

Screening vs. Confirmatory Tests

Initial immunoassay screenings are quick and inexpensive but prone to false positives due to cross-reactivity. Confirmatory tests like GC-MS or HPLC are more specific and accurate, identifying individual compounds. If an initial screen is positive, a confirmatory test can resolve ambiguity.

Medical Lab Tests: Biotin's Significant Role

Biotin (vitamin B7), often included in B-complex supplements, is a well-documented cause of false results in many medical lab tests, as warned by the FDA.

Specific Tests Affected by Biotin

High biotin doses interfere with tests using biotin-streptavidin technology, leading to falsely high or low results. This can impact:

Cardiac Tests: Falsely low troponin can lead to a missed heart attack diagnosis.
Thyroid Tests: Falsely low TSH and high FT4/FT3 can mimic hyperthyroidism.
Hormone and Pregnancy Tests: Interference can cause false negative pregnancy tests and affect hormone level results.

Navigating False Positives: What to Do

Minimizing the risk of false positives from supplements involves being proactive:

Steps to Mitigate Risk

Inform Testing Personnel: Provide a full list of all medications and supplements.
Temporarily Discontinue Biotin: Your doctor may advise stopping biotin before sensitive medical tests.
Choose Reputable Supplements: The supplement industry is not strictly regulated. Select high-quality products and check ingredient labels to avoid contaminants.
Request Confirmatory Testing: If an initial drug screen is positive, ask for a GC-MS confirmatory test.


Feature	Vitamin B12 (Cyanocobalamin)	Biotin (Vitamin B7)	B-Complex Supplements	Confirmatory (GC-MS)	Screening (Immunoassay)
Directly Causes Drug FP?	No	No	Potential, if contaminated with hemp-derived THC	No, confirms specific compounds	Yes, due to cross-reactivity or contaminants
Directly Causes Lab FP?	No	Yes, on hormone/cardiac tests	Possible, if contains Biotin	Not relevant to interference	Yes, for Biotin-sensitive tests
Primary Mechanism	None	Analytical Interference (Biotin-Streptavidin)	Contamination or cross-reactivity from other ingredients	Confirms exact molecular structure	Detects similar-shaped molecules
FDA Warning Issued?	No	Yes, for specific tests	No, but addresses ingredients	No	No

Conclusion

While vitamin B12 itself doesn't cause false positives, B-complex supplements containing it can. Riboflavin from hemp oil can cause false positives for THC on drug tests. Biotin commonly interferes with medical lab tests for thyroid and cardiac markers. Initial screenings are less reliable than confirmatory tests. Disclosing all supplements to healthcare providers is essential for accurate results.

For more information on the FDA's warning regarding biotin interference, visit the official safety communication.

FDA Drug Safety Communication: The FDA cautions that biotin may interfere with lab tests

Frequently Asked Questions

High doses of pure vitamin B12 are not known to cause a false positive on standard drug tests. The risk is more related to other ingredients sometimes found in B-complex supplements, such as riboflavin derived from hemp products.

Biotin (vitamin B7) is the B vitamin most frequently associated with causing false positive medical lab test results, particularly for thyroid function tests and cardiac troponin. For drug tests, riboflavin (vitamin B2) sourced from hemp oil is a potential cause.

If your supplement contains ingredients like biotin or is sourced from hemp, inform your healthcare provider and the testing facility. For sensitive medical tests, you may be advised to stop taking the supplement for a few days. If a drug screen comes back positive, request a confirmatory GC-MS test.

To avoid a false positive, disclose all supplements to the testing administrator, choose high-quality products from reputable brands, and, if instructed by a doctor, temporarily stop taking supplements containing biotin before certain lab tests.

An initial drug screen (immunoassay) is a rapid test that detects classes of drugs and can be prone to false positives due to cross-reactivity. A confirmatory test (GC-MS or HPLC) is a more specific and accurate method that separates and identifies individual compounds, confirming or refuting the initial result.

Yes, high levels of biotin can interfere with certain lab-based hCG pregnancy tests, potentially leading to a false negative result.

No, biotin specifically interferes with tests that use biotin-streptavidin technology. This includes certain hormone tests (thyroid, hCG) and cardiac troponin tests. Many other lab tests are unaffected.