The accuracy of most diagnoses gathered in the study was less than 50% due to a lack of diagnoses thereof in many cases or incongruity with the corresponding medical records. This result supports the report by Wandee Wansrisuthon et al.(12) The possible reason why overall coding accuracy was below 60% is that coders didn’t encode or omit it when physicians failed to diagnose. This was consistent with the report by Pantip Sawasdimongkol et al.(10) Consequently, the disease data base of Siriraj Hospital and the nation is incomplete and inaccurate, further affecting the data required for claiming medical expenses as previously shown by Wansrisuthon et al.(11) This issue points to the urgency to make physicians realize the importance of accurate, complete diagnoses congruent with the written medical records, together with regular and effective follow-ups, medical record evaluation, and coding monitoring and control.คำศัพท์ทางการแพทย์