When Should Complete Blood Count Tests Be Performed in Primary Total Hip Arthroplasty Patients?

Background: Routine laboratory studies are often obtained following total hip arthroplasty (THA). Moreover, laboratory studies are often continued daily until the patient is discharged regardless of medical management. The purpose of this study was to investigate the use of routine complete blood count (CBC) tests following THA. Secondarily, the purpose was to identify patient factors associated with abnormal postoperative lab values. Methods: This retrospective review identified 352 patients who underwent primary THA at a single institution from 2012 to 2014. Preoperative and postoperative CBC values were collected along with demographic data, use of tranexamic acid (TXA), and transfusion rates. Logistic regression models were used to identify factors associated with an abnormal postoperative lab and risk of transfusion. Results: Of the 352 patients, 54 patients were transfused (15.3%). Patients who underwent transfusion had a significantly lower preoperative hemoglobin (Hb; 12.0 g/dL) compared to patients who did not undergo transfusion (13.5 g/dL; P <.001). Patients who did not receive TXA were 3.7 times more likely to receive a transfusion. No patients received medical intervention based on the outcome of postoperative platelet or white blood counts. A Hb value below 11.94 g/dL for patients who are anemic preoperative or did not receive TXA predicted transfusion after postoperative day 1. Conclusion: Under value-based care models, cost containment while maintaining high-quality patient care is critical. Routine postoperative CBC tests in patients with a normal preoperative Hb who receive TXA do not contribute to actionable information. Patients who are anemic before THA or do not receive TXA should at minimum obtain a CBC on postoperative day 1.