Introduction: The recent advances in information and communication technology have increased the possibility to store and circulate information. EHR (Electronic health record) system, as an IT (Information Technology) in the healthcare field, can improve access to patient data. International research studies show that the benefits of e-health are significantly greater where EHR information can be shared and used by all involved in an individual's care. Messaging standards are critical for one system to communicate clinical data to another.

Methods: The study was qualitative and comparative in nature and is considered as an applied study. For the first section of study an assessment of interoperable EHR messaging standards relies on Grey literature source. Based on these findings we set out the best EHR activity about interoperable EHR messaging standards, initial messages with regards to the studied documents designed and translate for the second section and interviews with specialists for verifying the designed messages. 

Results: Results were presented in two sections. First, a comprehensive summary report of every message standard was presented. The report describes weaknesses and strengths of HL7 and openEHR standards. Among all the studied articles, we did not find weak points for openEHR. OpenEHR has benefits like future- proof and evidence-based and interoperability, HL7 is supposed to provide maximum interoperability among systems .However it has an interoperability problem between HL7 v2.x and HL7 v3 messages and interfacing between version 2.x and 3.0 is currently impossible. Second, the designed messages were presented based on the findings acquired through the interviews and workshops.

Conclusion: The evaluation of the EHR standards reveals no clear "winner". OpenEHR specifications over the past five years have had a significant influence on the development of EHR standards. Results show that openEHR facilitates the use of routine data for multi-centre clinical research. OpenEHR approach also ensures open, future-oriented Electronic Health Records, and it is highly desirable that multi-centre clinical trials adopt openEHR. In Iran the main focus is on HL7, in spite of the fact that there are some useful standards. Therefore, it is suggested that the whole current standards be studied and the weak and strong points of each standard be identified for use in the exchange of healthcare information.