Monitoring Anticoagulant control
Before starting coumarin anticoagulants, send a citrated specimen (blue top) for a baseline value accompanied by a coagulation request form. Please tick the RHS "INVESTIGATIONS" box for a baseline prothrombin time (PT) and activated partial thromboplastin time (APTT) to assess liver function and the presence of acquired anticoagulants. If relevant, specify other coagulation investigations, e.g. lupus, anticardiolipin antibodies or thrombophilia screen. (See under Blood Coagulation Investigations).
Complete the ANTICOAGULANT THERAPY ward card with clinical details of diagnosis and, if relevant, operative details, DRUGS and previous anticoagulant therapy. This card is a prescription sheet to be filled in with the drug dosage as you enter the daily (or less often if easily controlled) INR. It could be left on the end of the bed for ease of checking by senior medical staff.
For subsequent anticoagulant control, please send a citrated (blue top) specimen accompanied by a blood coagulation request form with details completed under "ANTICOAGULANT THERAPY." If concurrent unfractioned Heparin is administered, the APTT ratio is requested and, provided the heparin is not overdosed, this will not materially affect the PT on which to base further anticoagulant dosage of Warfarin.