Selecting heparin doses based on weight has been found to provide Partial Thromboplastin Time (PTT) results that are more likely to be within the desired therapeutic range and to fluctuate less when doses are adjusted. A protocol can help clinical personnel quickly and accurately select the appropriate dosage based on the patient’s weight and PTT values. Nurses and pharmacists can initiate and manage these protocols, saving time for both them and physicians. A weight-based heparin protocol also helps provide timely adjustments to dosages, which in turn helps to decrease the risk of adverse drug events.