**13. Near patient coagulation tests**

ACT and TEG are the two most common Near Patient Tests (NPT) used in cardiac surgery. The main value of NPT is the short turn-around time, which gives feedback to the treating physician/surgeon without delay. An ACT reading can be obtained generally within 4 minutes of test initialisation, and a TEG within 10 to 15 minutes. A conventional coagulation screen generally has a turn-around time of 30 minutes, during which time one or more interventions may already have taken place, making the result less valuable and potentially obsolete.

#### **ACT (Activated Clotting Time)**

This is generally performed at the bedside or in the operating room by a perfusionist or doctor who is actively managing the patient. A pre-heparin baseline value is obtained to assist interpretation of subsequent results. Anticoagulation whilst on cardiopulmonary bypass (CPB) is usually guided by ACT, and the test is also used to assess success of protamine reversal of heparin when CPB is over. After Protamine, an ACT that is prolonged beyond the baseline value suggests heparin reversal may be incomplete, but it offers no information regarding other potential causes of coagulopathy.
