Increased blood count and C-reactive protein are mostly caused by infections. When an infection is present, it is important to determine the severity by symptoms but also in combination with other aspects. The blood count and ultrasensitive C-reactive protein are auxiliary tests that are used to make a general judgment. A particularly high white blood cell count or high ultrasensitive C-reactive protein in routine blood tests may indicate a serious inflammation when the patient’s symptoms are not severe, and it is important to identify and treat the cause. It is also possible that the increase in these two tests is due to other causes, but if combined with the patient’s symptoms of infection, it can be determined that it is due to an infection. If the patient does not have an infection at this time, but has other conditions such as trauma or gastrointestinal bleeding, the increased values of these two tests are due to other causes.