||3 mL (1.5 mL min) serum from 1 SST. Separate serum within 2 hours of collection in a plastic transport vial and freeze immediately. Ship frozen. DO NOT THAW. Avoid food rich in indoles like avocado, banana, tomato, plum, walnut, pineapple, egg plant (brinjal) and also avoid tobacco, tea and coffee 3 days prior to specimen collection.