What kind of test results can confirm the diagnosis of hemophagocytic syndrome? Dr. Zhao Wang: In fact, phagocytic syndrome is a clinically comprehensive diagnosis, and no single positive test for any specific indicator is sufficient to diagnose phagocytic syndrome. Although the theory of primary phagocytic syndrome is simple, it is not diagnosed by doing a few genetic tests. This is because in the case of heterozygous mutations, additional tests are required to make the diagnosis. Moreover, some patients carry purely heterozygous mutation genes, yet they may not develop the disease for a long time. Wang Zhao from the Department of Hematology at Beijing Friendship Hospital once had an Italian specialist come to our hematology department and mentioned that he treated a child who was diagnosed with hemophagocytic syndrome when his brother had already developed the disease and his sister was tested to carry the disease gene. The Italian specialist thought it was likely that his sister would develop the disease, but after more than a decade of monitoring, the girl had grown up, married and had children, and was still healthy and did not develop the disease. Therefore, the diagnosis of primary phagocytic syndrome requires a comprehensive evaluation of clinical symptoms in addition to genetic testing. As for the diagnosis of secondary phagocytic syndrome, it is more complicated because there are no specific indicators. Fever, cold, hepatosplenomegaly, whole blood cytopenia, and even decreased NK cell activity are not diagnostic, but rather a comprehensive judgment. Especially for adults, if they have hepatitis, they may have hepatosplenomegaly; if they take medication or have a fever, they may have platelets and leukopenia; if they have hyperlipidemia, they may have elevated triglycerides …… In fact, these symptoms are very complex. If it is far-fetched to say that five out of eight can be diagnosed as phagocytic syndrome by satisfying them, then the disease will be expanded. In other words, the eight diagnostic criteria cannot be cross-referenced rigidly one by one? Dr. Wang Zhao: Yes. The diagnosis of hemophagocytic syndrome is a comprehensive decision made by an experienced physician based on the clinical course of the disease, the degree of endangerment, and specific laboratory test indicators. It should be emphasized that although liver function impairment is not among the eight diagnostic criteria, I believe that unexplained liver function impairment is actually an important hint for diagnosis.