All That You Wanted to Know About the ELISA Test and More

All That You Wanted to Know About the ELISA Test and More

By Terry Godier, Medical practitioner,

Terry Godier, Medical practitioner,

ELISA is a popular acronym for an enzyme-linked immunosorbent test that detects as well as measures antibodies in the blood. The test is generally administered to determine if the person’s blood that is being tested contains any antibodies that indicate the presence of specific infections. Antibodies are nothing but proteins that the human body produces as a response to antigens, which are substances that are harmful to the human body. Typically, the ELISA test is performed to establish whether a person has diseases like HIV, Lyme disease, Rocky Mountain spotted fever, Pernicious anemia, Rotavirus, Syphilis, squamous cell carcinoma, varicella-zoster virus, which is responsible for causing chicken pox and shingles, and Toxoplasmosis. The ELISA assay is usually advised by healthcare professionals to persons displaying symptoms of these diseases as a screening tool to establish or rule out any of the mentioned conditions.

How Is the ELISA Test Administered?

The administration of the ELISA assay is extremely simple, needing just a signed consent of the person undergoing the test after the doctor has explained what an Elisa test is used for and what the procedure is. The ELISA test is conducted on a sample of blood taken from you. The typical procedure for drawing the blood sample involves the cleansing of your arm by a healthcare provider with an antiseptic. After that, a tourniquet is tied on the arm to make the vein swell with the pressure of the blood and a sample drawn with a hypodermic needle. After an adequate volume of blood has been collected, the needle is removed and the injection site covered with a small bandage to stop the flow of blood.

"​The way the ELISA test results are reported depends on the method followed by the particular laboratory that is conducting the analysis"

Save the prick of the needle, the procedure is painless though some people experience a little throbbing of the arm for some time. No special preparation is required for the test; however, it may be wise to alert the healthcare provider if you have a fear of needles or are inclined to faint at the sight of blood. There are almost no risks associated with the collection of the blood sample save a minor risk of infection of the site of the needle insertion. Warn the doctor if you suffer from a bleeding disorder or have experienced problems in the past when giving blood.

The Testing Process

The blood sample will be analyzed in a laboratory, where the technician will take a Petri dish with the specific antigen for the condition that you are being tested for and add the blood sample to it. If the blood sample contains antibodies that react with the supplied antigen, a binding reaction will occur. Further confirmation will be done by the technician by the addition of an enzyme to observe its reaction with the blood and the antigen. If the contents of the Petri dish change color, it is likely that you may have the condition that you were being tested for—the extent of the color change indicates to the technician how much the antibody is present in the blood.

Result Reporting

The way the ELISA test results are reported depends on the method followed by the particular laboratory that is conducting the analysis as also the medical condition for which the test was conducted. Irrespective of the way the laboratory reports the test results, the interpretation and explanation should be done by a qualified healthcare professional. Though we are accustomed to the term HIV-positive, it may happen that a positive result in the report may actually mean that the condition is absent. Both false positives and false negative are known to happen, and if there is a suspicion that this has occurred the test may have to be repeated.


Even though the test administration and procedure are relatively simple, it is natural for you to be anxious while waiting for the screening result. Taking the test is completely voluntary but it is usually in your best interest to take it if you display symptoms of any condition for which the test is valid. Ignoring the test may result in a delay in commencing treatment that could be crucial to your well-being.

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