The best method is by indwelling cannula with samples transferred to heparinised tubes. The best method is to ask subjects to spit into polypropylene tubes. Do not stimulate saliva production. Do not collect more frequently than every 20 minutes as the relationship with plasma melatonin may be changed. Subjects should not eat within 30 minutes of sampling and must wash out their mouths with tap water before spitting.
Some nutrients interfere with assay in saliva.
Saliva left in plastic pipettes for more than 2-3 minutes may give falsely elevated melatonin levels. A. Ask subjects to collect all urine passed over a preset period into a standard urine bottle. A. Ask us to give a firm quotation - we are very reasonable. There is discount for bulk orders. It indicates darkness to the body.