How well do Croatian laboratories adhere to national recommendations for laboratory diagnostics of chronic kidney disease (CKD)?

Background In 2014, the Joint Croatian Working Group (JCWG) for laboratory diagnostic of chronic kidney disease (CKD) conducted a survey across medical-biochemistry laboratories which demonstrated a large heterogeneity in this area of laboratory medicine. To ensure the tools for the standardization process, in 2017 the JCWG-CKD published the first Croatian recommendations for laboratory diagnostics of CKD. To assess the implementation process, we have repeated a survey to explore how well laboratories adhere to the recommendations. Methods An invitation to the survey was sent to all Croatian medical-biochemistry laboratories (n = 196). The questionnaire was designed in a form of 19 questions and statements, with possible multiple answers. Results The response rate was 98/196 (50.0%). The predominant method for serum creatinine measurement was the standardized compensated Jaffe method (79.2%). There was substantial decrease in the number of laboratories which measure creatinine with the non-standardized uncompensated Jaffe method, compared with the initial 2014 assessment; 7% vs. 40%, respectively. The number of the laboratories that did not report estimated glomerular filtration rate (eGFR) values decreased almost by half compared to the initial data (37.6% vs. 74.4%). However, compared to the 2014 initial assessment, a similar number of laboratories (54/98 vs. 58/80) did not measure urine albumin or protein. Conclusions The collected data showed a substantial improvement in the standardization of the serum creatinine measurement, as well as in the reporting of eGFR. However, albuminuria or proteinuria assessment is still not implemented nationwide, mainly in primary health care laboratories. This demonstrates the importance of promoting and monitoring implementation of guidelines after publication.