Short for “rotational thromboelastometry,” this is a modification of the older technology known as TEG (thromboelastography). Both TEG and ROTEM use point-of-care devices that analyze whole blood clotting properties, and are helpful in rapidly analyzing a patient’s overall coagulation status, especially in cardiac surgery, liver transplant, and trauma settings. In both ROTEM and TEG, a pin attached to a detection device is inserted into a cup of fresh blood collected from the patient being tested. The main difference between TEG and ROTEM (aside from some minor terminology variations) is that in TEG, the entire cup rotates around the pin, while in ROTEM, the pin rotates back and forth within the cup. The basic principle is that as a clot forms, the pin will sense increased resistance, and that resistance is detected and charted (see the diagram from the TEG entry). Use of both technologies has been shown to decrease transfusion substantially in appropriate clinical settings.