Serum or plasma concentration of immunoglobulin G (IgG) antibodies against *Rickettsia* spp. (Rickettsia-specific IgG antibody)

What This Test Measures

This test checks for the presence of *Rickettsia*-specific IgG antibodies in your blood. IgG antibodies are a type of immune protein your body makes after being exposed to a pathogen like *Rickettsia*. If your body has encountered this bacteria before, your immune system will produce these antibodies. The test helps determine whether you may have had an infection in the past, even if you don’t currently have symptoms.

Why It’s Done

Doctors may order this test if you have symptoms like fever, rash, headache, or muscle aches that could suggest a *Rickettsia* infection. It’s also used in areas where certain tick-borne illnesses are common. This test is not typically used to diagnose active infection but can help assess exposure history or guide further testing if needed.

Sample Collection and Preparation

A blood sample is taken from a vein in your arm. The blood is processed to separate serum or plasma, which is then tested for IgG antibodies against *Rickettsia*. No special preparation is needed, but fasting may not be required unless specified by your healthcare provider.

What to Expect Before the Test

You may experience mild discomfort or bruising at the injection site. If you’re nervous, let your healthcare provider know so they can take steps to make you more comfortable. Avoid heavy exercise or alcohol before the test, as it may affect test results.