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Published on: August 19, 2020
Whole blood international normalization ratio measurements in children using near-patient monitors
William L Nowatzke1, Michael Landt, Carl Smith
1Department of Pathology, Washington University School of Medicine, St. Louis, MO, USA.
Insights
Four near-patient international normalization ratio (INR) monitors were compared in children. The RapidpointCoag showed the least bias, but bedside INR testing should supplement, not replace, lab measurements.
Area of Science:
- Clinical Chemistry
- Pediatric Hematology
- Point-of-Care Testing
Background:
- Accurate monitoring of warfarin therapy is crucial for preventing thromboembolic events and bleeding complications.
- Near-patient testing (NPT) devices offer rapid international normalization ratio (INR) results, potentially improving patient management.
- Evaluating the accuracy and precision of NPT INR monitors in pediatric populations is essential.
Purpose of the Study:
- To compare the performance of four different whole blood INR monitors used at the bedside.
- To assess the accuracy and precision of these devices in pediatric patients receiving warfarin therapy.
Main Methods:
- INR measurements from 19 pediatric subjects (30 visits) on warfarin were analyzed.
- Four NPT monitors (CoaguChek, Hemochron Jr. Signature, ProTime, RapidpointCoag) were compared against a laboratory plasma INR method (CA-1000 Analyze).
- Precision was assessed using adult volunteers, and interference from bilirubin was evaluated.
Main Results:
- The RapidpointCoag demonstrated the least bias compared to the laboratory reference method (r² = 0.923).
- Other monitors showed strong correlations: CoaguChek (r² = 0.877), ProTime (r² = 0.885), and Hemochron Jr. (r² = 0.834).
- Coefficients of variation ranged from 4.9% to 22.3%; bilirubin up to 20 mg/dL did not interfere.
Conclusions:
- Near-patient whole blood INR monitors provide acceptably accurate and precise results in children.
- However, NPT INR values can differ significantly from laboratory reference methods.
- Data from NPT devices should augment, not replace, routine clinical laboratory INR testing.
Purpose:
To report a comparison of international normalization ratio (INR) measurements on four near-patient (point-of-care or bedside) whole blood INR monitors in children.
Patients And Methods:
The INR results from 19 ambulatory pediatric subjects (30 hospital visits) receiving warfarin sodium were analyzed on four near-patient monitors and compared with plasma INR measurements on the laboratory CA-1000 Analyze. The instruments evaluated were CoaguChek, Hemochron Jr. Signature, ProTime Microcoagulation System, and RapidpointCoag.
Results:
The INR measurements ranged from 1.05 to 5.25. Over the entire INR range, the near-patient instrument with the least bias relative to the CA-1000 was the RapidpointCoag (r(2) = 0.923). The correlations (r(2)) of the CoaguCheck, Hemochron Jr., and ProTime were 0.877, 0.834, and 0.885, respectively. Precision studies involved repeated analysis of one nonmedicated adult (mean CA-1000 INR = 0.908) and one adult receiving oral anticoagulation therapy (mean CA-1000 INR = 2.42). The coefficient of variation on the near-patient monitors for both adult volunteers ranged from 4.9% to 22.3%. Bilirubin levels up to 20 mg/dL did not interfere in any of the methods.
Conclusions:
Near-patient testing whole blood INR monitors offer acceptably accurate and precise measurements. Values obtained on near-patient monitors may vary considerably from the reference method, and data obtained should serve as a supplement to, but not a replacement for, routine clinical laboratory measurements.
