Introduction: Registration of information obtained from laboratory findings, is an important method of transferring the results by laboratory professionals and can be of great help to diagnosis patient's clinical problems. Determination of data elements of this part has an important role in designing an electronic health records system. This study, aimed to determine the minimum data set of laboratory reporting system.

Methods: The participants of this cross-sectional, descriptive applied study, conducted in the first half of 2015, consisted of 95 laboratory staff working in Shahid Rajaee Cardiovascular, Medical and Research Center in Tehran. Data was collected using a researcher made questionnaire consisting of 11 parts the validity and reliability of which were determined through content validity and test_ retest method, respectively. The data were analyzed using SPSS software.

Results: According to the findings, the highest mean scores were related to final diagnosis (9/6), test result (9/4), test date (9), insurance credit date (8/4), and kind of anesthesia (8/7) while the lowest mean scores were related to referring physician's address (3/8), test tools (3/3) and Social History (5/3).

Conclusion: Considering the significance of laboratory data and information in the diagnosis and treatment of patients and the role of information systems in collecting, processing and distributing this information, it is crucial to pay attention to the minimum set of data related to these reports such as demographic, administrative, clinical, insurance, anesthesia and laboratory, observation and interpretation for exchanging with electronic health record system.