Infectious Disease Panel (Serum/Plasma)

What This Test Measures

The panel typically includes tests for markers like C-reactive protein (CRP), procalcitonin, and possibly white blood cell counts. CRP is a protein that rises when inflammation—often due to infection—occurs. Procalcitonin is a hormone released by cells during serious infections, especially bacterial ones. White blood cell counts help assess immune response.

When You Might Need This Test

Your doctor may order this test if you have symptoms like fever, fatigue, sore throat, or unexplained pain. It’s also used before surgeries, during pregnancy, or if you have a weakened immune system. Some tests may be done to monitor chronic conditions or rule out infections in routine check-ups.

Preparation and Process

No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if certain components of the panel require it. A healthcare provider will insert a needle into your arm to collect blood. Results are usually ready within 24–48 hours, depending on the lab.

Possible Results and Next Steps

High levels of CRP or procalcitonin suggest an active infection, while normal levels may mean no infection is present. If results are abnormal, your doctor will discuss further testing or treatment options, such as antibiotics or additional bloodwork.