BACKGROUND: Clinical laboratory services are at the forefront to support healthcare services, particularly during the pandemic of COVID-19. The increasing number of private clinical laboratories at present days indicates the increase in patient needs, causing the healthcare service provider to face challenges as people have more options. Therefore fostering patient loyalty (PL) is a crucial success factor for the business growth of clinical laboratories as healthcare providers.   AIM: The purpose of this study is to analyse antecedents of patient satisfaction (PS) in clinical laboratories towards PL with the switching cost (SC) and location (LO) as moderating factors. METHODS: This study was done as a quantitative survey, and data were obtained by a cross-sectional approach with partial least squares structural equation modeling (PLS-SEM) for the data analysis method. There are 266 respondents eligible as samples, who undergo the phlebotomy process in a private laboratory located within a specific area. RESULTS:  This study demonstrated that all the 9 hypotheses supported with α: 0.05 and p < 0.05, include 6 independent variables named administrative process (AP), information availability (IA), the environment in the phlebotomy room (ER), phlebotomy process (PP), waiting time (WT) and result notification (RN) that influence PS. Patient satisfaction has been shown to have a direct effect on patient loyalty and also mediate the antecedents. Furthermore, SC and LO have demonstrated a significant effect to moderate this relationship. CONCLUSIONS: Patient satisfaction has been confirmed as the main construct to predict PL whereas the AP is the most important independent variable followed by IA. Clinical laboratory management should pay more attention to these antecedents in order to ensure PS and retain the clinic’s patients. The cost from the patient's perspective should be taken into account since this helps the clinical laboratory keep the patient loyal.