The table below shows the white blood cell counts from the blood samples of three different patients.
| Patient | Concentration of white blood cells (cells / mm3\text{mm}^3mm3) |
|---|---|
| Patient P | 5,500 |
| Patient Q | 14,200 |
| Patient R | 7,800 |
Explain why the data in the table suggests that Patient Q has an active infection.