I would like to give my response to Mungmunpuntipantip and Wiwanitkit's Letter to the Editor, "Late diagnosis of COVID-19 and hypercoagulable state" [1], which cited my paper "Late diagnosis of COVID-19 in a 34-yearold man in a hypercoagulable state: A case report" [2].Based on the case, this patient was initially treated by an internist in a small hospital and was diagnosed and treated as Dengue Hemorrhagic Fever patient; however, there was no improvement and the condition even worsened, oxygen saturation decreased, then the patient was referred to a larger hospital. After a Polymerase Chain Reaction (PCR) examination, the results were positive, and then the patient was diagnosed and treated as COVID-19 patient, but because the patient already had a severe hypercoagulable condition, the patient could not be helped [3][4][5].