Fill test tube completely PT, PTT, TPT, Protein S, Protein C Proper mixing prevents clot formation Anti-Thrombin III, Lupus Anti-Coagulant Serum Tube with clot activator 4ml 2219 Serum testing for chemistry tests. Allow 30 min. for clot formation 10ml 2222 Digoxin, Dilantin, Drug Levels, Homocystine ... Test Tube Chart and Order of Draw Guide ...