Routine Postoperative Complete Blood Counts Are Not Necessary After Most Primary Total Hip and Knee Arthroplasties

Routine postoperative complete blood count tests are commonplace after total joint arthroplasty. The goal of this study was to identify if these result in any clinically meaningful action and if it would be safe to forego this testing in a population without known risk factors for transfusion.

A retrospective review of 1060 patients undergoing a total knee or total hip arthroplasty at a single institution was performed. Data points including patient demographics, preoperative and postoperative laboratory results, tranexamic acid use, preoperative and postoperative medication for venous thromboembolism prophylaxis and anticoagulation, as well as 90-day readmission related to anemia were collected.

The transfusion rate for all patients was 0.66% (7/1060) and there was only one transfusion for a patient with a preoperative hemoglobin (Hb) greater than 12 g/dL (1/976; 0.1%). There was no difference in the change from preoperative to postoperative day 1 Hb levels in patients treated with aspirin compared with those on direct oral anticoagulation (P = .73). There were no 90-day readmissions related to acute blood loss anemia.

This study demonstrates that routine postoperative complete blood count testing is not absolutely necessary and does not provide additional value in the vast majority of patients with preoperative Hb levels equal to or greater than 12 g/dL when tranexamic acid is administered. This could avoid unnecessary testing in patients and increased savings to the health care system.

Level 3, retrospective cohort.