How far back can mouth swab detect opiates?

For all type of drugs standard detection time for hair test is 90 days (if you hair grows up slowly , possible extra 10-12 days). If they collect hair from the body (hair on the head is under 1-1,5 inches) detection can go up to 1 year (body hair grows up much slower ). Standard is 90 days because Labs use first 1,5 inch of hair (close to the scalp) for testing.