In addition, there were concerns relating to anti factor Xa test standardization and reproducibility, weak correlation be- tween bleeding events and anti factor Xa concentrations,101 and no evidence that anti factor Xa testing is needed for patients with obesity. The panel identified the following additional research ques- tions. (1) What are the anti factor Xa concentration cutoffs (determined in a manner that ensures accuracy and reproduc- ibility) that correlate with risk of recurrent VTE and bleeding events? (2) What percentage change in LMWH dose in response to an out-of-range anti factor Xa concentration is optimal to return the concentration to the therapeutic range? (3) What is the comparative effectiveness of adjusting LMWH doses based on the results of anti factor Xa concentrations (performed in a manner that ensures accuracy and reproduc- ibility) vs no such monitoring for patients with obesity requiring treatment of VTE? Question: For patients receiving DOAC therapy for the treatment of VTE, should measurement of the DOAC anticoagulant effect vs no measurement of DOAC anticoagulant effect be used during management of bleeding? For patients receiving DOAC therapy for the treatment of VTE, the ASH guideline panel suggests against measuring the DOAC anticoagulant effect during management of bleeding (conditional recommendation based on very low certainty in the evidence about effects ). Summary of the evidence. We found no relevant systematic reviews but did identify 8 studies106-113 that included patients on DOACs receiving treatment of bleeding, some of whom had measurements of the DOAC anticoagulant effect using a variety of tests (eg, activated partial thromboplastin time, anti factor Xa concentrations, and thrombin time), but none had a primary objective of evaluating the impact of measuring DOAC anticoagulant effect or reported a direct comparison of outcomes for patients who did and did not receive DOAC anticoagulant effect measurement. 