Figure 1.

Depictions of normal or physiologic TEG (top) and ROTEM (bottom) tracings. TEG and ROTEM use equivalent but independently labelled parameters. Reaction time (R) and clot time (CT) refer to the time required for the transducer to be displaced 2 mm, correlating with the parameters of the PT/aPTT tests. Clot formation/kinetics (k) and clot formation time (CFT) are measures of initial clot strength and clot formation kinetics, referring to the time required for the transducer to be displaced 20 mm after it reached the 2 mm mark. α-angle is the angle formed between the horizontal axis and the sloped line formed between 0 and 20 mm of amplitude and is used in both TEG and ROTEM technologies. CFT/k and α-angle are broadly correlated with fibrinogen levels. Clot amplitude at 5/10 min (A5/A10) are measurements of the amplitude at 5-min intervals after the CT. Maximum amplitude (MA) and maximum clot firmness (MCF) refer to the maximum displacement acquired and are measures of maximum clot strength. They correlate with maximum clot retraction as a reflection of the crosslinking of fibrin with platelets. TEG and ROTEM analyzers also use differing parameters to describe fibrinolysis. Lysis at 30 min (LY30) shows the percent decrease in amplitude 30 min after achieving MA. Clot lysis index at 30 min (CLI30) is the residual clot remaining 30 min after CT, measured as a percentage of MCF. Maximum lysis (ML) is a measure of the percent decrease in amplitude at the end of the run. Adapted from [23] with permission from Semin Thromb Hemost., 2020.