Khas does have some Morphine / Codeine.
Morphine levels in poppy seeds range between 4–200 mg/kg. According to an article published in the Medical Science Law Journal, after ingesting "a curry meal or two containing various amounts of washed seeds" where total morphine levels were in the range 58.4 to 62.2 µg/g seeds, the urinary morphine levels were found to range as high as 1.27 µg/mL (1,270 ng/mL) urine. Another article in the Journal of Forensic Science reports that concentration of morphine in some batches of seeds may be as high as 251 µg/g. In both studies codeine was also present in the seeds in smaller concentrations. Therefore it is possible to cross the current standard 2,000 ng/mL limit of detection, depending on seed potency and quantity ingested. Some toxicology labs still continue to use a cutoff level of 300 ng/mL.