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Generational performance of three point-of-care testing devices compared with standard laboratory measurement of the international normalised ratio across extended ranges
  1. Hui Ming Tay1,
  2. Yi Feng Lai2,
  3. Ming Chai Kong3,
  4. Edmund See3,
  5. Shu Hui Yeang3,
  6. Sei Keng Koh3,
  7. Yuan Tying Shim2,
  8. Fiona Seet Ling Chan4,
  9. Wan Hui Wong1,
  10. Clifton Xuan You Liew1,
  11. Hartirathpal Kaur1,5,
  12. Chuen Wen Tan1,
  13. Liam Pock Ho4,
  14. Wai Yoong Ng4,
  15. Chin Pin Yeo4,
  16. Heng Joo Ng1
  1. 1 Department of Hematology, Singapore General Hospital, Singapore, Singapore
  2. 2 Department of Pharmacy, Sengkang General Hospital, Singapore, Singapore
  3. 3 Department of Pharmacy, Singapore General Hospital, Singapore, Singapore
  4. 4 Department of Pathology, Singapore General Hospital, Singapore, Singapore
  5. 5 Blood Services Group, Health Sciences Authority, Singapore, Singapore
  1. Correspondence to Dr Hui Ming Tay, Department of Hematology, Singapore General Hospital, Singapore 169856, Singapore; tay.hui.ming{at}

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Point-of-care testing (POCT) of the international normalised ratio (INR) is recognised as a rapid and reliable alternative to venous INR measurement for titration and monitoring of patients anticoagulated with vitamin K antagonists.1–4 Besides empowering patient self-testing and self-management,5–7 POCT coagulometers are now widely used in healthcare institutions for bedside anticoagulation management and have replaced venous INR sampling in many anticoagulation clinics (ACCs).8–10

For the past decade, our institution has been using the CoaguChek XS system (Roche Diagnostics, Basel, Switzerland) for INR testing at our outpatient ACC and inpatient anticoagulation service. This followed a validation study conducted by our group which showed excellent correlation with venous INR below a reading of 3.5.11 A tendency for a higher INR on the POCT platform above this threshold prompted us to introduce a mechanism that rejected results above 3.5 on the CoaguChek XS system and mandating repeat testing with venous INR. This test protocol remains in effect today.

Recently, two new fourth-generation coagulometers were introduced on the CoaguChek platform. The CoaguChek Pro II is designed for institutional use with the added capability of measuring activated partial thromboplastin time while the CoaguChek INRange is targeted at patients performing home INR monitoring. These machines have the same detection system as the CoaguChek XS devices but uses the new CoaguChek PT Test strip which has a broader intended use compared with the XS devices’ test strip.12 We evaluated the performance of these two coagulometers for INR testing with a validation study comparing their performance against the old CoaguChek XS Pro and standard venous INR. The results were intended for us to conduct a review of our current POCT INR test protocol. This paper reports the findings of our efforts.

Materials and methods

Study design and study population

This prospective validation study comparing three different POCT coagulometers against venous INR was …

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