Serology

Serologic tests focus on proteins made within the immune system to fight off “intruders” like viruses and bacteria. The results of serologic tests performed at a clinical laboratory can help doctors accurately diagnose various diseases and determine whether or not certain treatments are effective.

Why Serologic Testing is Needed

Serologic testing is performed to look for antibodies in the immune system. Antibodies are blood proteins the immune system produces in response to antigens that get into the body through the nose, mouth, or other openings. Common antigens that may trigger a response from the immune system include fungi, viruses, parasites, and bacteria. Serologic testing may be needed to:

• Identify the specific type of antigen triggering a response from the immune system
• Determine whether or not the body is mistakenly attacking healthy tissues
• Evaluate the effectiveness of various medications meant to help the immune system fend off intruders

How Serologic Testing is Done

Serologic testing is performed on a blood sample that’s either taken at a clinical lab or sent to a lab for analysis. The sample can be collected by inserting a needle into the skin or with a lancet, the preferred method for younger children or patients who have an aversion to needles.

Types of Serologic Tests Performed

Various tests will be performed on samples in order to identify possible antibodies. Multiple tests are often needed due to the diverse nature of antigens.

An agglutination assay is a test that looks for a behavior within the immune system known as particle clumping. It’s an action that sometimes occurs in response to exposure to certain antigens.

A precipitation test is done to determine if the antigens present in a sample are similar. The test measures for the presence of various antibodies in fluids. Related tests include the Ouchterlony (double diffusion) and Mancini test.

Antimicrobial antibodies may be identified with the Western blot test. It’s usually a follow-up test done to evaluate the reaction to specific antigens. For instance, the test may be used to confirm that a patient has the HIV virus or Lyme disease.

Interpreting Serologic Testing Results

Normal results for a serologic test will show no antibodies at all. This means the patient does not have a current or former infection. Antibodies present in a sample indicate that the patient’s body is fighting some type of infection or virus. Results may determine if a patient has conditions such as:

• Autoimmune diseases
• Fungal infections
• Parasitic conditions, like amebiasis
• Measles or rubella
• Bacteria-based conditions, like brucellosis

By providing this testing service, we help medical professionals and patients receive the answers they need to make appropriate treatment decisions.