Why does it take 10 days for a nicotine level and metabolites blood test to come back?
It depends on the sensitivity and specificity of the rapid test used to detect the presence of contine. The 10-day wait is probably for a more confirmatory GCMS test, which requires specialized equipement (like a gas chromatograph). I bet it’s sent to an outside lab. If your rapid test is not very sensitive, then the confirmatory test could still be positive. The sensitivity level could be set too high, like above 200 ng/mL when the actual urine concentration is 150 ng/mL. In that case, GCMS would still detect the contine, but the rapid test would show a false-negative.
