Whether a cold is a viral or bacterial infection can be determined from symptoms, laboratory tests, etc. If you want to clarify the pathogen, you can check throat swabs, sputum cultures, or antibodies to influenza viruses, but it is of little significance to clarify the pathogen. Bacterial colds usually have a slower onset of symptoms, accompanied by more obvious purulent discharge, such as coughing up yellow sputum and yellow nasal discharge. The symptoms of viral colds are mainly characterized by fever and sore throat, and cough and runny nose are characterized by white sputum and clear nasal discharge, accompanied by generalized muscle aches and pains. Laboratory examination of bacterial cold, white blood cells, neutrophils, C-reactive protein, calcitoninogen will have a more obvious elevation, sputum smear can find bacteria. In viral colds, white blood cells, neutrophils and calcitonin are not elevated, the percentage of lymphocytes is elevated, and C-reactive protein is not significantly elevated. If you want to make a clear diagnosis, you can consult a doctor to identify the pathogens through throat swab, sputum culture or blood test for influenza virus antibody to identify the pathogens in response to the symptoms of colds, but colds are usually self-limiting illnesses, and symptomatic treatment is the mainstay of treatment, and identifying the pathogens is not of much significance.