BACKGROUND Routine blood tests following total shoulder arthroplasty (TSA) cost the British national health system over £65,000 in 2018 without definite evidence of their impact on patients' outcomes. This study aimed to ascertain whether routine laboratory tests are necessary after elective TSA. METHODS A retrospective review of electronic records was completed for 274 patients that underwent TSA in the past six years. In total, 216 patients were eligible for analysis. The primary outcome was intervention rate for abnormal postoperative blood tests. Secondary outcomes were hospital length of stay (LOS), and readmissions at 30 and 90 days. RESULTS In total, 193 patients underwent 216 TSAs; 72% were female, and the mean cohort age was 78 ± 7.2 years. Overall, 136 patients (63%) had an abnormal postoperative blood test, however; only 8 (3.7%) required intervention. The average postoperative drop in haemoglobin (Hb) was 19g/l. In four patients (1.8%) Hb levels dropped to < 80g/l; however, only two (0.9%) were symptomatic and received a red blood cell transfusion. Six patients (2.8%) developed acute kidney injury and did not require haemofiltration. The mean LOS was 3.2 ± 2.9 days. Five patients (2.3%) were readmitted within 30 days and six patients (2.8%) within 90 days. Univariate analysis only showed association between patients with abnormal creatinine and LOS (p < 0.05), and all of these patients had raised preoperative creatinine levels. CONCLUSIONS Routine postoperative blood tests are not required as they did not change the clinical outcome in this cohort or the readmission rate, causing unnecessary costs. It is recommended to request postoperative blood tests for patients with raised preoperative creatinine levels.