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Title CoaguChek XS Should Not Replace Laboratory Plasma INR Tests Prior to Large Dental Surgeries
Clinical Question How accurate are CoaguChek XS INR values compared to laboratory plasma INR values for patients taking Warfarin?
Clinical Bottom Line For patients taking Warfarin, CoaguChek XS point of care INR monitor is less precise and less accurate than laboratory plasma tests in obtaining accurate INR values. Laboratory plasma INR values are the gold standard and should be used prior to large dental surgeries.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 22118602Christensen/201114 papers evaluating CoaguChek XS in patients taking WarfarinSystematic Review
Key resultsCoaguChek XS’s correlation of variation ranged from 1.4% - 5.9% (ideal CV for INR defined as <3%) and the correlation coefficient ranged from 0.91 – 0.95. INR values within therapeutic range had higher precision and accuracy.
#2) 22862752Miltra/201272 patients suspected of having acute traumatic coagulopathySingle-center, prospective blinded comparative study
Key resultsCoaguChek XS sensitivity and specificity values are 63.1% (95% CI: 46.0% – 77.7%) and 88.2% (95% CI: 71.6% – 96.2%), respectively. The PPV and NPV of CoaguChek XS are 85.7% and 68.2%, respectively (note: PPV & NPV not included in the article; calculated from Table 2 data input at www.medcalc.org).
Evidence Search “sensitivity and specificity” AND point of care AND international normalized ratio
Comments on
The Evidence
Validity: Christensen study: Very little information was given about the 14 CoaguChek XS study methodologies. This study also evaluated other brands of point of care INR monitors (not included in key results). The authors’ conclusion is, “the accuracy of POCT coagulometers seems, in this respect, to be generally acceptable, and they can be used in clinical settings.” The authors are referring to a clinical setting such as a care facility where INR values are taken daily to determine need for adjusting Warfarin doses. This study did not advocate using this type of test prior to invasive procedures. Miltra study: This study used a convenience sample. This is the only study found with sensitivity and specificity values for any point of care INR monitor. Patients in this study were not orally anticoagulated (i.e. Warfarin), but instead developed a coagulopathy secondary to traumatic injury. The authors note that acute traumatic coagulopathy often has multiple etiologies, which differs from Warfarin-induced coagulopathy. It is unknown if the results are similar to CoaguChek XS values in patients taking Warfarin. Perspective: The anticipated amount of hemorrhage should play a large role in determining safe clinical applications for CoaguChek XS utilization in dentistry. Although the point of care INR monitor is easier and cheaper for the patient than traditional laboratory plasma INR tests, it may not be the safest option.
Applicability More CoaguChek XS clinical studies are needed due to varying precision and accuracy results for patients taking Warfarin. It would be ideal to have a study that calculated CoaguChek XS’s sensitivity, specificity, PPV and NPV in patients taking Warfarin. CoaguChek XS should be used with caution in patients with INR values above therapeutic value (i.e. above 3.0, depending on cited source) due to increased chance of error; these are the patients that we need the most accurate INR values prior to dental surgery. CoaguChek XS seems most appropriate for daily patient monitoring to determine a need for Warfarin dose adjustments.
Specialty/Discipline (Endodontics) (General Dentistry) (Oral Surgery) (Periodontics)
Keywords CoaguCheck XS, Warfarin, Coumadin, INR, international normalized ratio, point of care
ID# 2515
Date of submission: 07/31/2013spacer
E-mail chadwick@uthscsa.edu
Author Jane Chadwick, DDS
Co-author(s) Michael Hosking, DDS
Co-author(s) e-mail hosking@uthscsa.edu
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