American Society for Clinical Pathology and American Society for Clinical Laboratory Science

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November 7, 2022

Do not measure the INR in patients who are taking an anti-Xa inhibitor.

Anti-Xa inhibitors (e.g., rivaroxaban [Xarelto®], apixaban [Eliquis®]) are commonly prescribed anticoagulants. Their indications include (but are not limited to): reducing the risk of stroke or systemic embolism in patients with nonvalvular atrial fibrillation; treating deep venous thromboembolism (DVT) and pulmonary embolism; and DVT prophylaxis. Bleeding is a common complication from anti-Xa inhibitor use that may require reversal with andexanet alfa, prothrombin complex concentrate, or plasma. While the INR is commonly used to measure the anticoagulation effect of vitamin K antagonists (e.g., warfarin), it is insensitive for anti-Xa inhibitors, potentially leading to inappropriate patient management decisions.

These items are provided solely for informational purposes and are not intended as a substitute for consultation with a medical professional. Patients with any specific questions about the items
on this list or their individual situation should consult their physician.

How The List Was Created

(1–4) The American Society for Clinical Pathology (ASCP) list of recommendations was developed under the leadership of the ASCP Effective Test Utilization Steering Committee. This committee is chaired by an ASCP Past President and is comprised of subject matter and test utilization experts across the fields of pathology and laboratory medicine. The committee considered a list of possible recommendations compiled as the result of a survey administered to Society members serving on ASCP’s many commissions, committees and councils. In addition, an announcement was made to ASCP’s Advisory Board seeking suggestions for possible recommendations to promote member involvement. The laboratory tests targeted in our recommendations were selected because they are tests that are performed frequently; there is evidence that the test either offers no benefit or is harmful; use of the test is costly and it does not provide higher quality care; and eliminating it or changing to another test is within the control of the clinician. Implementation of these recommendations will result in higher quality care, lower costs and a more effective use of our laboratory resources and personnel.

(5) This recommendation was developed under the leadership of ASCLS’s Choosing Wisely Committee and the ASCLS Board of Directors. The Committee examined numerous options based on evidence available. Subject matter experts from the ASCLS Scientific Assemblies reviewed, edited, and recommended approval of this recommendation, which was subsequently reviewed and approved by the ASCLS Board of Directors.


Gosselin RC, Adcock DM, Bates SM, Douxfils J, Favaloro EJ, et al. International Council for Standardization in Haematology (ICSH) Recommendations for Laboratory Measurement of Direct Oral Anticoagulants. Thromb Haemost. 2018. 118(3):437-450. DOI: 10.1055/s- 0038-1627480

Milling Jr. TJ, Frontera JA. Exploring Indications for the Use of Direct Oral Anticoagulants and the Associated Risks of Major Bleeding. Am J Manag Care. 2017. 23(4 Suppl):S67- S80.

Cuker A, Burnett A, Triller D, Crowther M, Ansell J, et al. Reversal of direct oral anticoagulants: Guidance from the Anticoagulation Forum. Am J Hematol. 2019. 94(6):697-709. DOI: 10.1002/ajh.25475