title: Is perioperative point-of-care prothrombin time testing accurate compared to the standard laboratory test?
abstract: 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.
authors.affiliation: University Department of Anesthesiology and Pain Therapy, University Hospital of Bern, Bern, Switzerland.
authors.forename: Natalie
authors.initials: N
authors.lastname: Urwyler
authors.forename: Lukas P
authors.initials: LP
authors.lastname: Staub
authors.forename: Dominik
authors.initials: D
authors.lastname: Beran
authors.forename: Marcus
authors.initials: M
authors.lastname: Deplazes
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Lord
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Alberio
authors.forename: Lorenz
authors.initials: L
authors.lastname: Theiler
authors.forename: Robert
authors.initials: R
authors.lastname: Greif
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016063:Blood Loss, Surgical / Q000503:physiopathology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care; D019095:Point-of-Care Systems; D011517:Prothrombin Time; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors