# Dynamic and Quantitative Assessment of Blood Coagulation Status with an Oscillatory Rheometer
## 3 Results
### Intrinsic Coagulation  
A further coagulation assay (aPTT, intrinsic coagulation) was performed in this work to verify that the oscillatory rheometer can detect and even differentiate the coagulation process from the already investigated PT assay. Citrated blood was activated with Pathromtin and CaCl\({}_{2}\) to investigate the activated partial thromboplastin time. Preliminary experiments showed that measurements with 1 Hz and a shear stress of 0.04 Pa did not provide repeatable results, because inertia effects were dominating. Therefore, a frequency of 0.1 Hz with the same shear stress was used to obtain the results in Figure 2. Elastic and viscous shear moduli initially showed a short \"lag phase\" before both changed rapidly over time, similar to the PT (Figure 2a,b). This reflects the strength of the activator, which is stronger  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & **Kineus Pro** & **KC 1A** & **Kineus Pro** & **m (G\({}^{\prime\prime}\)/Pa s\({}^{-1}\))** & **m (G\({}^{\prime\prime}\)/Pa s\({}^{-1}\))** \\ \hline Control & 25\(\pm\) 1.0 & 25\(\pm\) 3.3 & 185 \(\pm\) 4.5 & 1.7 \(\pm\) 0.4 & 6.0 \(\times\) 10\({}^{-1}\)\(\pm\) 0.8 \(\times\) 10\({}^{-1}\) & 12\(\times\) 10\({}^{-1}\)\(\pm\) 0.3 \(\times\) 10\({}^{-1}\) \\
0.5 IU/mL & 40.3 \(\pm\) 1.2 & 40.5 \(\pm\) 1.3 & 186 \(\pm\) 3.9 & 1.8 \(\pm\) 0.2 & 4.4 \(\times\) 10\({}^{-1}\)\(\pm\) 0.7 \(\times\) 10\({}^{-1}\) & 9.0 \(\times\) 10\({}^{-2}\)\(\pm\) 18\(\times\) 10\({}^{-2}\) \\
0.8 IU/mL & 51.4 \(\pm\) 1.3 & 48.8 \(\pm\) 4.5 & 17.5 \(\pm\) 3.9 & 2.0 \(\pm\) 0.4 & 1.4 \(\times\) 10\({}^{-1}\)\(\pm\) 0.8 \(\times\) 10\({}^{-1}\) & 2.3 \(\times\) 10\({}^{-2}\)\(\pm\) 13\(\times\) 10\({}^{-2}\) \\
1.0 IU/mL & 72.3 \(\pm\) 4.2 & 68.4 \(\pm\) 7.3 & 1.8 \(\pm\) 0.5 & 6.5 \(\times\) 10\({}^{-1}\)\(\pm\) 0.7 \(\times\) 10\({}^{-1}\) & 8.6 \(\times\) 10\({}^{-3}\)\(\pm\) 2.3 \(\times\) 10\({}^{-3}\) & 42\(\times\) 10\({}^{-3}\)\(\pm\) 12\(\times\) 10\({}^{-3}\) \\
1.5 IU/mL & (\(\mu\) = 4) & 131.5 \(\pm\) 7.4 & 102.7 \(\pm\) 10.3 & 0.5 \(\pm\) 0.3 & 3.0 \(\times\) 10\({}^{-1}\)\(\pm\) 0.5 \(\times\) 10\({}^{-1}\) & 1.2 \(\times\) 10\({}^{-3}\)\(\pm\) 0.8 \(\times\) 10\({}^{-3}\) & 9.0 \(\times\) 10\({}^{-4}\)\(\pm\) 6.3 \(\times\) 10\({}^{-4}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparative data of Kinexus Pro and KC 1A for the measurement of the prothrombin time (PT) (\(\mu\) = 10). Citrated blood without and with various concentrations of heparin was activated by Thromberel. Summary of the clotting time (CT), elastic (G\({}^{\prime}\)) and viscous (G\({}^{\prime\prime}\)) shear moduli at 300 s and linear slopes (m (G\({}^{\prime}\)) and m (G\({}^{\prime\prime}\))).  
for the Prothrombin assay. Similar to the PT assay shown above, the linear slopes and values for elastic (G\({}^{\prime}\)) and viscous (G\({}^{\prime\prime}\)) shear moduli were determined here as well and the calculated clotting time compared to the reference device KC 1A.  
Table 2 summarises the obtained values. It is clearly obvious that here is no significant difference between the clotting times determined via Kinexus (43.7 \(\pm\) 3.9) s or KC 1A (44.1 \(\pm\) 4.3) s (Table 2, Appendix A Figure A5).  
Comparing the linear slopes and the G\({}^{\prime}\) and G\({}^{\prime\prime}\) at 300 s between PT and aPTT measurements (Kinexus), these are significantly lower with aPTT assay than with PT assay (Appendix A Figure A6a-d), indicating a slower coagulation and less firm clot stability in aPTT. Thus, as the oscillatory rheometer and the ball coagulometer provided significantly different results for the two coagulation assays (PT and aPTT), both devices are therefore capable to differentiate between these two coagulation methods.