ELISA blood test


What is an ELISA Blood Test?

ELISA, or Enzyme-Linked Immunosorbent Assay, is a method of analyzing the presence of a specific antigen or protein within a sample, typically a patient’s blood. The ELISA test specifically looks for an antibody linked to the protein of interest by exposing a sample of the patient's blood to a target antigen that produces a binding reaction when the two come into contact. When the antigen and antibody connect, this produces a color change in the sample, which is detected and can be used to diagnose or monitor disease.

Preparation for the Test

The preparation for the ELISA test depends on the form of the test being done. If a screening test is being done, no prior planning is necessary. If the test requires facetotum-specific planning or fasting 12-14 hours prior, the patient should be advised to do so. In addition, the patient must provide a medical history and informed consent before the test can be done.


Once the sample is obtained, it will be placed into an ELISA plate and incubated. During this period, antibodies will attach to any antigen present in the sample. The plate is then washed to remove any unbound material, and an enzyme-linked secondary antibody is added. This antibody binds to the antigen-antibody complex and is recognizable by the enzyme marker on the plate. After further washing to remove unbound material, a color change will occur on the plate where the antigen-antibody complex was present, which indicates a positive result.


There are several different types of ELISA tests, which vary depending on the type of sample being tested and the purpose of the test. Some examples include HIV tests, HIV viral load tests, Hepatitis B and C tests, Lyme disease tests, and tests for celiac disease. Different tests require different sample types, such as serum, saliva, urine, or stool.


ELISA tests are generally considered safe with minimal risk to the patient. They do not involve injections or needles and the only risk is the potential for contamination of the sample, which can lead to false results.

Why is it Done?

The ELISA test is performed to detect the presence of a specific antigen in a sample. These antigens can be used to diagnose or monitor different diseases or conditions, such as HIV or Hepatitis B and C.

When is it Used?

The ELISA test is used in a variety of situations. It is commonly used to diagnose and monitor different infectious diseases, ranging from simple viral illnesses to more serious conditions like HIV and Hepatitis B and C. It is also used to detect allergens in an individual's body, such as those responsible for causing allergic reactions.