Back to Biotin for hair loss guide
Washout plan
Assumes a morning draw. Stop dates use the conservative end of each evidence window.
Assay interference
8–72 h
Thyroid, hormones, troponin
Dose in mg, last dose time.
Sandwich assays often false low; competitive often false high.
Metabolic artifact
Disclose
Creatinine, eGFR
Dose and duration; hold only if the clinician prefers.
The creatinine number is usually real. Filtration may still be fine.
Meter interference
Say so
Some POC glucose meters
Date of infusion; ask for lab glucose if a meter will be used.
Ordinary oral vitamin C is a different exposure.
Background intake
Disclose
Usually none of the immunoassay rows
Still list the bottle.
AACC has not reported immunoassay interference at ≤1 mg.
Organ injury
Not a pause
ALT, AST
Clinician workup, not an assay pause.
Stopping for 8 hours does not convert true liver injury into a clean baseline.
Assay interference
48-72 h
FOBT / guaiac cards
Last dose and the daily amount.
Ascorbate can turn a bleeding-positive card negative.
Metabolic artifact
Skip a.m. dose
Serum iron, TSAT
Dose and the time of the last tablet.
Serum iron reads the morning pill; ferritin barely moves.
Background intake
Pill-driven
Serum B12
Say you take B12; ask whether MMA was checked.
The level measures your supplement, not your stores.
How to use this
- Tap what you take. Nothing selected, nothing on the slip.
- Set your blood test date and the tool builds a washout timeline: stop dates for ingredients with evidence-backed windows (biotin immunoassays, vitamin C and guaiac cards), same-morning skips where that is the honest answer (iron studies), and disclose-only rows where no real washout exists.
- If the bottle only prints mcg, type it. 5,000 mcg is 5 mg — that band is the immunoassay row.
What this does not do
No diagnosis, no “upload labs,” no order to stop levothyroxine, anticoagulants, diabetes drugs, or clinician-prescribed high-dose biotin. Herb-related enzyme rises are organ-injury workups, not 8-hour assay pauses. Emergency troponin is never delayed for a gummy washout.