A positive IgM test for novel coronavirus pneumonia indicates infection with a novel coronavirus. The human body can have an immune response to the novel coronavirus infection, and some antibodies can be present, including IgM antibodies to novel coronavirus pneumonia. The presence of IgM antibodies to novel coronavirus pneumonia in the early stages of infection can be used as an auxiliary test to confirm the diagnosis of novel coronavirus pneumonia, but the main basis is the nucleic acid test for novel coronavirus pneumonia. The nucleic acid collection for novel coronavirus pneumonia may be affected by the course of the disease, the specimen collection, the testing process, and the testing reagents, which can result in false negatives. In order to improve the positive rate of the test, it is important to standardize the collection of specimens and go for the test as soon as possible after collection.