Hello, everyone. My name is Manxiang Li. I'm a doctor from Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Xi'an Jiaotong University. Today, we're going to talk how to diagnose Coronavirus disease 2019, COVID-19. We know for all types of diseases usually we based on three things to do a final diagnosis. The first is history, the second is clinic futures, the third one is run blood test. Because COVID-19 is an epidemic, we need to know epidemiological history for this particular disease. There are four points we need to understand for this COVID-19. The first one is a history of travel or residence in Wuhan city and neighboring areas or other areas with confirmed infection cases within 14 days before onset of disease. Here, there are two things we need to emphasize. One is why we need to emphasize Wuhan? Because the first case was diagnosed in Wuhan Hubei Province, and why we need to pay attention to 14 days? Because the latent period for this COVID-19 is usually like 3-7 days. But it should be less than 14 days. So we need to pay attention for 14 days for one patient, whether he has or has not this disease. The second part is a history of contacting patients confirmed with infection with COVID-19 within 14 days before onset of disease. The third point is a history of contacting patients with fever or respiratory symptoms after a travel or residence in Wuhan or neighboring areas, or other areas with confirmed infection cases within 14 days before disease onset. So that's means a patient had contact with another patient. This patient has a fever and respiratory symptoms, but also he has a travel and a residence history in Wuhan or in any area that has a confirmed infection cases. So the patient needed to be take care and to screen weather he has or she has COVID-19 or not. So the third point is aggregate occurrence. Because this is an epidemic, we need to know whether there was a similar patients occurrence in one place in a short-term like in a family or in the same office, whether two or more patience has similar symptoms like fever or respiratory infection? If yes, we know there is aggregate occurrence for this kind of disease. So the second thing is we needed to know is the clinical manifestation. Of course, because this is a respiratory epidemic disease. So we needed to know whether she has some respiratory symptoms, she has a fever, she has a fever notch, dry cough, and [inaudible] or not. Sometimes we need to pay attention whether he or she has a sputum and so on. So the second thing is, we need to do a blood routine test to pay attention to white blood cell number and the lymphocytes number. You are in the early stage of this disease. So the blood white cell and the lymphocyte really should be decreased. The third thing in clinical manifestation is imaging features. Usually, we do [inaudible] film, but most long term we do CT scanning to see whether the patient's lung has some change like ground-glass opacity or patchy shadow. Here we have some typical imaging for CT, we see that in the left lung there are some patch shadow, in right CT scanning we see in both lung we see some ground-glass opacity. It's not consolidation but it is ground-glass, so it's not completely consolidation. So based on the before three points, we needed to make a decision whether this patient is a suspected cases or is completely not COVID-19. So two types of treachery we needed to pay attention. First is, if you have one epidemiological history plus two clinical manifestation, you are a suspected cases. Another thing is you haven't the particular history, but you have all three types of clinical manifestation. So you are suspected cases. So for confirmed cases that's means, this patient, we count him as suspected patients cases. We needed to know whether she or he finally is a COVID-19 infection or not. We needed to do some particular tests on this patient. So there are two or three types of tests we needed to know. First one is nucleic acid by RT-PCR to find whether she has or he has COVID-19 nucleic acids. Usually, we get samples from throat swab or blood to do it, or we can do the [inaudible] to do a nucleic acid test. The second thing is we use the same symbol to do genetic sequencing. See whether we can find some homologous with no COVID-19 sequence. The third thing is antibody. Either it is an IgM or IgG antibody. In early stage, it should be IgM, but in a recovery stage, natural stage, it should be IgG. But compared with the nucleic acids or genetic sequencing, antibody is not so acute. Sometimes it has a high false positive results. It's hard to make a final decision. So once we've diagnosed the patient as COVID-19, we need to do classification because we need to choose a place for this particular patient to cure treatment. We have four types of classification. The first one is silent infection. We also call it sub-clinical patients. That's means the patient is infected with the COVID-19 but the symptoms is very slight or without any symptoms, without an imaging manifestation of his abnormal chest. The second type is mild pneumonia. That means the patient's condition is okay, is not so bad. You have a fever, you have a respiratory symptoms and also in your lung, we can see some imaging changes like the ground-glass opacity, but your condition is not so bad. We call it a mild pneumonia. The third type is a severe one, that means your disease condition is slowly progressive to bad. So except the fever, except the blood tests that changed, except the CT scanning changes, you need to meet the following. Either one of three types of these. The first one is you have increased respiratory rate, your respiratory rate is more than the 30 times per minute or you have a hypoxia, without any oxygen therapy, the pulse oxygen sensuality should be less than 93 percent. The third one is the ratio of artery oxygen pressure with [inaudible] inspiration oxygen less than 300-millimeter mercury. So the last one is a very severe one, critical cases. So for this patient, you should have one of these three types of things. Then you can be quantified as critical cases. You need to be transferred to ICU to get an enhanced treatment. The first one is, you have respiratory failure, you'll need to get mechanical ventilation is, [inaudible] The second one is shock, so that means your blood pressure is very low. The third one is combined with multi-organ failure. Like your heart, your kidney, and some important organ. The function is gone bad and bad. So the last thing we need to know the differential diagnosis because we know COVID-19 occurred in winter and the spring. Right now, it is early spring, but in this winter and spring, it's like a season for influenza and other virus infection like a common cold. So we need to distinguish the difference whether it's rare COVID-19 infection or is a common cold, or some other virus infection. Of course, bacterial pneumonia is also very common in this kind of condition, in this kind of seasons. Also, we need to get rid of non-infectious diseases like some vasculitis, dermatomyositis. This is because sometimes they have similar symptoms and they have similar changes in the CT scanner? So thank you so much for your attention I'm glad to be here to talk about the diagnosis and different diagnoses of this COVID-19
