Retrospective analysis of inappropriate laboratory testing

The use of laboratory tests in health care is frequent and interest in laboratory tests has been increasing over the last decades. Despite the increasing use of tests, a positive relationship between the frequency of laboratory use and quality of patient care has not been reported. Therefore, most of the requested tests are considered to be inappropriate or unnecessary. In this study, we aimed to evaluate the laboratory use of our institution in a 3-year period covering the years 2015-2017 based on objective criteria retrospectively and cross-sectionally in terms of the suitability of test repetitions. For this purpose, we evaluated inappropriate repeated rates of hemoglobin A1c (HbA1c), 25-OH vitamin D, thyroid stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), anti-thyroid peroxidase antibody (anti-TPO), vitamin B12, folate, iron, ferritin and total cholesterol in the light of clinical guidelines. For the 11 parameters we examined, inappropriate repeated test rate of 3-year was found to be 10% on average. Inappropriate repeat rates ranged from 4% to 17.8%. In TSH, fT3 and fT4 parameters, inappropriate repeated test rates were in the range of 4% - 5.4%, while the range differed between 12.4% and 17.8% for 25-OH vitamin D, iron, ferritin and total cholesterol. In all tests (except anti-TPO), inappropriate repeat rates were found to be higher in inpatients each year of the 3 years. Improper repetition of total cholesterol, iron and ferritin parameters were frequent in men and anti-TPO was frequent in women. It was observed that there was no significant gender difference in inappropriate repetitions of other parameters. Inappropriate repeats were performed in all parameters (except HbA1c), particularly in folate and 25-OH vitamin D (minimum 83.5% - maximum 92.4%) after a result that had been in reference range. In HbA1c, 25-OH vitamin D, TSH, fT3 and fT4 parameters, inappropriate repeated tests were requested mostly from the endocrinology outpatient-clinic (%4,5 - %21,4). It was observed that inappropriate iron (51.1% - 52.3%) and total cholesterol (20.4% - 26.9%) were inappropriately repeated mostly from the oncology outpatient-clinic. It was found that the examined test repetitions were mostly inappropriate for the periods suggested in the guidelines. In order to reduce the non-conformity of laboratory test demands, it is very important to analyze the reasons and to cooperate with laboratory experts and clinicians.