Second, we hope to determine the accuracy of PCT as a marker of infection. Whenever we think a patient may have an infection, it is routine care to take some blood and run lab tests such as a white blood cell count, blood culture, and a C-reactive protein level. Patients in the study will also have an additional 10 drops of blood taken for a PCT level at the same time as the routine blood draw. Even though patients may show signs of an infection, the routine blood test do not always come back positive for an infection. We will compare the routine blood test results (positive or negative for an infection) with the PCT level taken at the same time. If most patients with an infection also have a rise in PCT and those patients without an infection have a normal PCT, then we will prove that PCT is a good, accurate marker for infection in our patients.