Abstract Reference values are an essential aspect of clinical laboratory testing, providing a basis for comparison of results against established norms for specific patient populations. These reference values are used to evaluate diagnostic test results, monitor disease progression, and assess treatment effectiveness. The accuracy and reliability of these values are crucial to the diagnosis and treatment of disease and illness and also important in the monitoring of disease progression and treatment effectiveness. By tracking changes in test results over time, healthcare providers can assess the effectiveness of treatments and make adjustments as needed. This information is critical in the management of chronic conditions such as diabetes and hypertension. Despite their importance, reference values can be subject to variability due to a variety of factors. These include differences in laboratory testing procedures, variations in patient populations, and differences in the methods used to establish reference ranges. To address these issues, clinical laboratories can use individual references calculated based on previous test results. Nevertheless, individual reference values can be subjected to pathophysiological alterations that can modify the values of specific analytes. The aim of this study was to investigate the impact of a clinical catastrophic event, specifically troponin levels above 1000, on the calculation of individual reference values for 21 analytes. Six measurements were taken before and after the event from a sample of 5 to 450 patients. The results showed that the mean and covariance coefficient of the majority of the analytes remained unchanged despite the presence of the clinical event. Applying a Wilcoxon test to the mean before and after the event 10 out of the 21 analytes differ significantly before and after the event. These analytes included glucose, BNP, chloride, gamma GT, hematocrit, hemoglobin, potassium, C-reactive protein and urea. The mean and covariance of the remaining 11 analytes, which included platelets, creatinine, alkaline phosphatase, magnesium, sodium, AST, ALT, TSH, fibrinogen, prothrombin time, and activated partial thromboplastin time (aPTT), were not significantly impacted by the clinical event. These results suggest that despite the presence of a clinical catastrophic event, individual reference values can still be calculated for the majority of the analytes. This is important for the accurate interpretation of clinical laboratory test results, especially in the presence of acute illnesses or injuries. However, caution should be exercised when interpreting results for the three analytes that were significantly impacted by the event. Further studies are needed to determine if similar results can be obtained for other clinical catastrophic events and analytes.