Elisa Vs. Western Blot Explained

This article has been reproduced with the kind permission of Peter Sotory

I've spent some time learning about the ELISA tests and the Western Blot test. To explain the concept to a friend, I made the graphics below which I think would be useful to others too. Just skip ahead to them and you can come back to the written explanation if they don't make sense. 

An ELISA test is a much weaker test than a Western Blot. ELISA looks at a single antigen (bacterial protein) to say if a patient has Lyme or not. In October 2010 a University of Medicine and Dentistry of New Jersey (UMDNJ) published a study saying that there are 13 strains of Borrelia (Lyme) Here is the story in Discover Magazinehttp://discovermagazine.com/2011/jan-feb/58 ). The current ELISA tests are based on just one strain, B-31. The ELISA test uses a single antigen from this strain as an attachment point for a patient's antibodies. Clearly this recent discovery of many more strains could mean that the single antigen of the ELISA test is not shared by all the strains. This might explain why the ELISA test often misses cases of Lyme. Some companies even use a synthetic version of the antigen.

ELISA is usually done because it is a cheaper test at about $75, while a Western Blot can run around $200 to check for early & late antibodies (IgM (~$100) and IgG (~$100)).

The Western Blot test runs a patients sample through an gel with the use of an electric current. The patients antibodies are complexed (bound) to broken up bacterial parts in the sample. The electric current drags these bound pairs through the gel. The different weighted pairs end up in different places in the gel with the lighter pieces moving the farthest. These different places are represented as bands in the gel. The bands create a pattern and there are patterns that indicate if antibodies have been bounded to Lyme bacterial parts. This can indicate if Lyme is present. The advantage of the Western Blot over the ELISA test is that far more indicators are examined than the single antigen in ELISA. Perhaps the 13 strains will differ in a couple of particular antigens, but when you start looking at many antibody complexes it will become more difficult to miss Lyme's presence.

Think about comparing cars, with different models representing different strains. If you check for only one thing like GPS navigation to define the vehicle as a car, you will miss a lot of models that aren't equipped with that feature. This one feature test for determining if a thing is a car would be like using the single feature ELISA test. But suppose you start comparing a bunch of features like GPS navigation, steering wheel, 4 doors, fuel injection, foglights, and Air conditioning as defining a thing as a car. With a greater selection of features you will properly identify more things as cars. This is like using the Western Blot test which is looking at a broader scope in identifying Lyme's presence through antibody activity.

Check out our 'western blot comparison' spreadsheet for a look at various bands tested across different labs.

Pictures are below.

Elisa Test:



Western Blot Test Process:



Antibodies Complexed With Bacterial Part Examples:

 

1. Elisa | 2. Melisa | 3. BCA Labs | 4. Igenex | 5. LLMD's | 6. Elisa vs WB