BACKGROUND The increasing demand for Total Hip replacement (THR)/Total Hip Arthroplasty (THA) continues to place significant financial pressure on the National Health Service (NHS). Many institutions undertake post-operative blood tests routinely in this group of patients. The aim of this study was to identify if such routine blood tests (Full Blood Count (FBC) and Urea and Electrolytes(U&Es)) are required in all THR patients post-operatively. METHODS Single institute, Multi-surgeon, retrospective observational study of consecutive patients who underwent primary elective THR done from Jan 2014 to Dec 2018.Post-operative blood tests and medical records were reviewed to identify derangement in haemoglobin (Hb) level and renal function requiring clinical intervention. RESULTS Over the period of 4 years, 353 patients underwent elective THR with mean age of 70 years (range: 42-90). There were 203 Males and 150 Females. Mean pre-operative Hb was 134.7 g/l. Mean post-operative drop in Hb was 22.3 g/l. None of the patients in ASA grade 1 and 2 with age ≤70 years required blood transfusion post operatively.6.4% of patients (n = 18/280) with an ASA of 1-2 had postoperative blood results requiring intervention of which only four (1.2%) were ≤70 years of age compared to 17.8% of patients (n = 14/73) with ASA 3-4.Overall none of the patients in ASA grade 1 and 2 with age ≤70 years required blood transfusion post operatively nor had electrolyte disturbance. 1.2% had deranged renal function that needed minor clinical intervention. CONCLUSIONS Routine post-operative blood analyses may not required for all patients undergoing THA. Young and healthier patients seldom have significant abnormalities on routine post-operative blood analyses which requires clinical intervention.