Summary
There is no accepted way of measuring prothrombin time without time loss for patients
undergoing major surgery who are at risk of intraoperative dilution and consumption
coagulopathy due to bleeding and volume replacement with crystalloids or colloids.
Decisions to transfuse fresh frozen plasma and procoagulatory drugs have to rely on
clinical judgment in these situations. Point-of-care devices are considerably faster
than the standard laboratory methods. In this study we assessed the accuracy of a
Point-of-care (PoC) device measuring prothrombin time compared to the standard laboratory
method. Patients undergoing major surgery and intensive care unit patients were included.
PoC prothrombin time was measured by CoaguChek® XS Plus (Roche Diagnostics, Switzerland). PoC and reference tests were performed
independently and interpreted under blinded conditions. Using a cut-off prothrombin
time of 50%, we calculated diagnostic accuracy measures, plotted a receiver operating
characteristic (ROC) curve and tested for equivalence between the two methods. PoC
sensitivity and specificity were 95% (95% CI 77%, 100%) and 95% (95% CI 91%, 98%)
respectively. The negative likelihood ratio was 0.05 (95% CI 0.01, 0.32). The positive
likelihood ratio was 19.57 (95% CI 10.62, 36.06). The area under the ROC curve was
0.988. Equivalence between the two methods was confirmed. CoaguChek® XS Plus is a rapid and highly accurate test compared with the reference test. These
findings suggest that PoC testing will be useful for monitoring intraoperative prothrombin
time when coagulopathy is suspected. It could lead to a more rational use of expensive
and limited blood bank resources.
Keywords
Point-of-care - prothrombin time - coagulation - anaesthesiology - blood loss