Clinical effects of calibration of CoaguChek XS PT Test Strips on Anticoagulation Management Services

In January 2018, Roche Diagnostics calibrated CoaguChek XS PT Test Strips to the latest World Health Organization reference preparation. On September 12, 2018, Roche Diagnostics issued an urgent medical device correction statement warning of inaccurate international normalized ratio (INR) results greater than 4.5 and recommended additional confirmatory testing. Eight weeks later, on November 2, the U.S. Food and Drug Administration issued a class I recall of all affected lot numbers. The objective of this project was to determine the clinical effects of recalibration of CoaguChek on patients managed by the Anticoagulation Management Services (AMS).

Two retrospective chart reviews were conducted for patients seen by AMS from May 1 to September 11 and from September 12 to November 2, 2018. Data collected included date of INR, confirmatory testing (if applicable), reason for elevated INR, and interventions. Data were analyzed using descriptive statistics.

From May 1 to September 11, 2018, 16 of 166 patients were affected by recalibrated strips, resulting in 19 of 1176 INRs being greater than 4.5. Almost half (47%) of elevations were due to unknown causes, and most were corrected by holding at least 1 dose. Of the 152 patients treated from September 12 to November 2, 8 patients were affected by the recalibration, resulting in 11 of 453 INRs being greater than 4.5. Six resulted in confirmatory INR testing with an average difference of 2 points. No bleeding events or hospitalizations were reported in either group.

Based on the experiences of 1 anticoagulation clinic, the CoaguChek XS PT Test Strip calibration update and class I recall did not result in a meaningful clinical impact.