The Cardiac Calculator is an educational tool for healthcare professionals only to provide information on heparin and/or protamine effect on the Clotting Time (CT) results on the ClotPro.
It is NOT for therapeutic heparin monitoring.
In cardiac surgery, the most important information provided by IN-test is not the absolute CT value but the ratio between CT in IN-test and HI-test.
Here, a significant heparin effect can be assumed if CT HI-test/CT IN-test >1.25.
A prolongation of CT in IN-test AND HI-test can have several reasons:
Blood sampling within 5-10 min after protamine administration
Factor XII deficiency (not factor XIII) which is not associated with bleeding
Other deficiency of enzymatic factors of the intrinsic or common pathway (factor XI, IX, VIII, X, V, II, and I)
Only the latter one should be treated with plasma transfusion in case of clinically relevant bleeding. Therefore, these results have to interpreted with care and always in the clinical context (as stated in the intended and indications for use).
If IN-test CT < 200 s, then NO Heparin or Protamine effect
If IN-test CT AND HI-test CT > 260 s, then Protamine effect: Wait 20 mins, then repeat
If IN-test CT > 200 s, then calculate ratio (IN-test CT / HI-test CT)