Basic Principles Of A ELISA Test

Basic Principles Of A ELISA Test

ELISA testing has become more popular these days. It is an enzyme-linked assay which is immunosorbent. It is a test that measures the antibodies present in your blood. 

It is highly used in the diagnosis and measurement of many different diseases and conditions. While the general public are not necessarily aware of how common ELISA testing is, those in medicine are aware that it is a highly used form of testing and is extremely important in managing health. 

ELISA kits for testing are available widely and can aid in medical diagnosis. 

But what do you need to know about ELISA testing, if you stick around we can tell you! 

What Is An ELISA?

ELISA is an acronym. It stands for ‘enzyme-linked immunosorbent assay’. This type of testing is a technique that is used to find and present antigen inside a biological sample. 

ELISA is much like many other immunoassay kinds, as it relies on antigens being detected by antibodies. It uses highly specific antibody-antigen interactions in this. 

The Basic Principles Of An ELISA

With ELISA testing, there are many different antigen and antibody combinations that are used. They will however, always include the use of an enzyme which is labeled as an antigen or as an antibody.

The activity of the enzymes will be measured in a way known as colorimetrically. 

This means that the activity of the enzymes is measured through the use of a substrate which will change its color when the enzyme modifies it. 

The antigens will be immobilized on a solid surface, it can be done by use of a capture antibody, or it can be done directly. 

However, once captured on a solid surface, the antigen is then complexed to a detection antibody which is then conjugated with an amenable molecule to detect, this can be done with a fluorophore or an enzyme. 

ELISA assays are often performed in multi-welled plates which will give a solid surface that is needed to immobilize the antigen in the first place. The immobilization of this aids in the separation of the antigen from all other components inside the sample. 

This is exactly why ELISA is so heavily used. It just makes it much easier to perform via many samples all at once. 

Being able to do this ensures more accurate results, and helps in faster diagnosing illnesses, and more. 

What Are The Advantages & Disadvantages?

No form of testing is perfect and even an ELISA test has its flaws. Let’s take a quick look at the advantages and disadvantages of ELISA testing. 


  • ELISA testing is highly sensitive and very specific. It is not uncommon for ELISA tests to detect an antigen even at a picogram level in a very specific form thanks to the use of the antibodies. 
  • ELISA tests are also high throughput. A commercial ELISA test can be found available in a well plate form of 96. However, assays can easily be increased to adapt to 384-well plates! 
  • These tests are also incredibly easy to perform. They are one of the easiest tests to do and the protocols for performing them are very easy to follow and there is minimal time hands on in doing them. 
  • ELISA tests are also very quantitative. They can easily detect the concentration of any antigen inside of a sample. 
  • ELISA tests will also allow you to test varying types of samples. You could test anything from a serum, plasma, urine, saliva, or even tissue or cellular extracts as well as many other types as well. Making it a versatile form of testing too! 


  • On the flip side, ELIA tests only have temporary readouts. The detection is based only on substrate or enzyme reactions, and this means that any readout must be obtained or completed in a very short time span. 
  • Another downside is that there is only limited antigen information. You see, the information is limited to the amount or the presence of the antigen found inside of the sample. So, a high concentration will give you more information, but a low concentration will give you less. 


ELISA testing is a very commonly used method of testing in diagnosis. It can measure antibodies inside of your blood, saliva, urine and more. It is most often used to diagnose things such as HIV, lyme disease, and types of anemia as well. 

It is a type of testing that has many advantages, and few disadvantages that has helped to enhance medical practices over the years. 


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