Related Experiment Video
Updated: Oct 29, 2025
Detection of Antibodies That Neutralize the Cellular Uptake of Enzyme Replacement Therapies with a Cell-based Assay
Published on: September 10, 2018
A retrospective analysis of discordances between international normalized ratio (INR) self-testing and INR laboratory
Joan Bitan1, Fanny Bajolle2,3, Annie Harroche4
1Hematology Laboratory, Hôpital universitaire Necker-Enfants Malades, AP-HP, Paris, France.
Insights
Discrepancies between home point-of-care (POC) and laboratory international normalized ratio (INR) testing in children are linked to younger age and the use of animal thromboplastin in lab tests. This highlights the need for specific quality control for POC INR devices.
Area of Science:
- Pediatric Hematology
- Clinical Diagnostics
- Point-of-Care Testing
Background:
- Quality control for home point-of-care (POC) international normalized ratio (INR) devices is a significant concern.
- Concomitant laboratory and POC INR testing can help address quality control issues.
- Differences between POC and laboratory INR results may not always indicate POC device failure.
Purpose of the Study:
- To identify variables associated with significant deviations between POC INR and laboratory INR measurements.
- To investigate factors influencing the accuracy of home INR monitoring in pediatric patients.
Main Methods:
- Retrospective cohort study involving children with paired laboratory and POC INR measurements.
- Analysis of clinical and laboratory variables to determine associations with significant INR deviations.
- Multivariate analysis to identify independent predictors of INR discrepancies.
Main Results:
- Significant deviations occurred in 15.3% of INR measurement pairs (30/196) from 124 children.
- Younger age (OR=0.91, P=.020) and laboratory use of animal thromboplastin (OR=2.81, P=.016) were associated with significant deviations.
- Less experience with POC INR devices showed a trend towards association with deviations (OR=0.89, P=.098).
Conclusions:
- While most INR pairs were consistent, deviations highlight the impact of laboratory thromboplastin origin.
- The findings underscore the necessity for specific quality control procedures for POC INR devices in pediatric care.
- Further investigation into thromboplastin sources and POC device validation is warranted.
Introduction:
The lack of quality control procedures for home point-of-care (POC) international normalized ratio (INR) devices is a concern. Concomitant laboratory and POC INR testing may be proposed to overcome the lack of quality control. However, a difference between the POC INR and the laboratory INR is not necessarily due to failure of the POC device. This study aimed to identify variables associated with a significant deviation between the POC INR and the laboratory INR.
Methods:
Children included in this retrospective cohort study performed at least one concomitant laboratory and POC INRs. Clinical and laboratory variables were assessed for an association with significant deviation within pairs of INR.
Results:
A significant deviation was noted for 30 (15.3%) of the 196 pairs of INR measurements from 124 children. Relative to patients without deviations, patients with deviations were younger (odds ratio =0.91; P = .020), less experienced in the use of POC INR devices (odds ratio =0.89; P = .098), and more likely to have received an INR result from a laboratory using animal thromboplastin (odds ratio =2.81 vs. 0.37 for laboratories using human thromboplastin; P = .016). In a multivariate analysis, younger age and the laboratory's use of animal thromboplastin were associated with significant deviations.
Conclusions:
Although most children had coherent pairs of INR values, the occurrence of deviations raises the question of the origin of the thromboplastin used in the laboratory and emphasizes the need to provide specific quality control procedures for POC INR devices.
