Serology and Serological Tests

Serology is a blood test used to detect antibodies in the blood. There are various types of serological tests, each designed to diagnose different diseases. All serological tests share a common focus: the proteins in the immune system.

The immune system is responsible for maintaining bodily health by destroying foreign substances that can cause disease.

Why are serological tests performed?

Serological tests help diagnose the cause of a disease and assess the activity of the immune system.

• Antigens are substances that trigger immune responses. They can enter the body through the mouth or skin wounds. Bacteria, fungi, viruses, and parasites are examples of antigens.
• The immune system produces antibodies to protect against these antigens. Antibodies are substances that bind to antigens and prevent them from causing harm. Blood tests can identify the type of antibody, antigen, and infection.
• In some cases, the body mistakenly identifies healthy tissues as foreign and produces unnecessary antibodies, leading to autoimmune disorders. Serological tests can detect these antibodies and autoimmune disorders.

Types of Serological Tests

Serological tests involve a simple blood draw. Due to the diversity of antibodies, there are many types of serological tests, including:

• Agglutination reactions measure the binding of antibodies to specific antigens.
• Precipitation measures the amount of antibody in body fluids and the similarity of antigens.
• Western blot detects the presence of antibodies in the blood based on their reaction with a target antigen.

Serological Test Results

Normal Results: If the results are normal, it indicates that the body is producing antibodies in response to antigens. The absence of antibodies means there is no infection.

Abnormal Results: The presence of antibodies in the blood indicates that the immune system has reacted to an antigen due to a past illness or infection. Antibodies can also indicate immunity to one or more antigens, meaning that if the individual is exposed to the antigen in the future, they will not become ill.

What Conditions Can Serological Tests Diagnose?

Serological tests can help diagnose various conditions and diseases, including:

• Brucellosis (caused by bacteria)
• Amebiasis (caused by parasites)
• Measles (caused by a virus)
• Rubella (caused by a virus)
• HIV
• Syphilis
• Fungal infections

What to Do After a Serological Test

Follow-up care after a serological test depends on the type of antibody detected and the state of the immune system. Antibiotics or other medications may be prescribed to treat infections. Even if the test results are normal, further tests may be performed to rule out infection. Bacteria, viruses, parasites, and fungi can multiply over time, causing the immune system to produce more antibodies. Test results can also indicate the presence of antibodies associated with chronic conditions such as autoimmune disorders.