a collection device for plasma preparation for diagnostic assays . the device comprises a spray - dried anticoagulant formulation on the interior surface of the device and a thixotropic polymeric gel . the device is an improvement over commercially available devices which contain liquid anticoagulant formulations , for use in nucleic acid testing that employ amplifications technologies including , but not limited to , polymerase chain reaction , branched dna and nucleic acid sequenced based amplification .