RESUMEN
Interval laboratory investigations are necessary for monitoring chronic diseases. However, testing too frequently may not be beneficial clinically and can be considered low-value care. We examined the frequency of glycosylated haemoglobin, lipids, iron panels (serum iron, ferritin, transferrin, iron binding) thyroid function (free T4 and thyroid stimulating hormone) and 25-OH vitamin D tests in a 1290-bed tertiary hospital in Singapore. All tests done over a 20-month period (January 2016 to August 2017) were retrieved from the laboratory database. Of the 275 565 tests done for 115 971 patients, 5.2% were repeat tests done at intervals shorter than the minimum retesting interval, as defined by the Royal College of Pathologist and Irish Guidelines on the Use of the Laboratory. Using the Centers for Medicare and Medicaid Services Clinical Laboratory Fee Schedule, we estimated a cost burden of US$222 096 per year. Strategies to reduce unnecessary repetitive testing can result in significant cost savings.