In contrast to hypocoagulability, hypercoagulability is difficult to detect clinically. In most cases, hypercoagulability is detected during or after insertion of a central venous catheter. Rarely, blood clots occlude the puncture needle resulting in several “dry” puncture attempts. Similarly, blood aspirated into an empty syringe upon vessel puncture rapidly clots in patients with hypercoagulability and cannot be ejected (Fig. 12.1). It is meaningful to use an empty syringe to puncture a blood vessel and routinely eject the blood from it at the end of the procedure to screen for hypercoagulability. In surgical patients with drains in place, visible or sometimes even palpable clots in drainage bags (Fig. 12.2) or containers can be a sign of hypercoagulability. Hypercoagulability is typically encountered during the initial phases of critical illness, particularly in conditions associated with a pronounced pro-inflammatory response such as sepsis, trauma or surgery. It is important to remember that bleeding may still occur despite clinical signs of hypercoagulability. These bleeding sources are usually amenable to surgical repair.