Preanalytics: The patient should lie during blood drawing. 1 day before the patient should abstain from coffee, tea, bananas, oranges and other citrus fruits no drugs like paracetamol, aspirin, aminophyllin, chloralhydrate, clonidine, dexamethason or duretics. mix blood tube well and centrifuge immediately, after centrifugation plasma can be stored up to 2 hours at room temperature, for longer storage plasma samples should be kept frozen at -20 °C Additional requests or shipment by post is not possible for this parameter.