INTRODUCTION: There has been an increase in 25-hydroxy vitamin D (25(OH)D) test requests and laboratory costs in recent years. At the end of 2019, the General Directorate of Health Information Systems issued a regulation calling for restricting vitamin D requests in primary care. We aimed to investigate the effect of this regulation on the requested numbers of 25(OH)D tests with the big data obtained from the national information health system of the Turkish Ministry of Health.
METHODS: Between 2016-2022, all inpatient and outpatient tests and 25(OH)D tests in all medical biochemistry laboratories in Turkey were determined based on department and institution type. Distribution among health institutions and test request rates were calculated.
RESULTS: The total number of 25(OH)D tests requested was increased from 2016 to 2022, except for 2020 and 2021, probably related to the COVID-19 pandemic. The yearly increase rate in 2017, 2018, 2019, and 2022 was 137%, 56%, 16%, and 5%, respectively. The number of 25(OH)D tests requested in primary care institutions decreased after the regulation. The total number of 25(OH)D tests requested in 2nd and 3rd Stage Public Health Facilities and private hospitals increased in 2022 compared to 2019.
DISCUSSION AND CONCLUSION: Our findings showed that the request for 25(OH)D testing decreased in primary care and increased in 2nd and 3rd Stage Public Health Facilities and private hospitals after the regulation was released. Despite the decrease in the yearly increase rate in the number of test requests, the annual number of tests requested is still high, suggesting that different measures should be taken.