Nobody has tested whether stopping biotin before a test works
One review advises stopping biotin more than 48 hours before a blood test, reasoning from how fast the body clears it. Regulators say there is not enough information to know.
What the study found
The 48 hour stop before a blood test was reasoned, not tested
One review advises stopping biotin more than 48 hours before a blood test, reasoning from how fast the body clears it. The US Food and Drug Administration says plainly that there is not enough information to know whether stopping for any number of hours prevents a wrong result.
The caveat · No help to people who cannot stop
The 48 hour figure is the review authors' inference from biotin's half-life, and no study they cite establishes that it clears interference at any dose. It also cannot help the people most exposed: someone arriving at an emergency department has no notice, and people taking biotin for biotinidase deficiency, a mitochondrial disorder or multiple sclerosis cannot stop.
What we don't know
Stopping biotin more than 48 hours before a blood test is advice reasoned from how fast the body clears it. No study has tested the interval, and the US regulator says there is not enough information to know if any stop works.