ELISA (ENZYME LINKED IMMUNOSORBENT ASSAY) and Western blot are both immunoassays.
They rely on the use of antigens and antibodies in the reaction.
Both these experiments are analytical in nature and are used to detect bio-molecules like proteins, enzymes, or other pathogens.
They are widely used in molecular biology, medical research and also in health care.
ELISA is a quantitative technique that is rapid and relies heavily on the production of colors.
While western blot protocol is a semi-quantitative technique that relies on the production of separated bands of biomolecules, it employs gel electrophoresis to separate the proteins.
Elisa and Western blot
Both these techniques are based on the immunology principle but, they have different procedures and applications. So we will see their similarities and differences in detail.
ELISA vs. Western Blot similarities.
Since they follow the same principle, there are few similarities between them.
| SL.NO | ELISA | Western Blot |
| Principle | Based on Immunological assay | Immunological assay |
| Method of assay | The reaction between an antigen and antibody forms a complex | Antigen antibody reactions form a complex |
| Type of sample | Biological samples | Biological samples only. |
| Compounds that can be analyzed | Proteins, enzymes, hormones, steroids | Enzymes, proteins, hormones. |
But they are many differences between these two techniques. These differences help the researcher decide which one of the two to take up.
ELISA vs Western Blot Differences.
| SL.No | ELISA | Western Blotting |
| Detects | Antibody or antigen in the tissue | Mostly the antigen in the tissue |
| Time duration for experiment | Very quick like in couple of minutes | Very time taking like 2 to 3 days. |
| Number of samples per experiment | Many sample can be analyzed in a single run like 96 samples per turn using plate readers | Only limited samples like 7 samples per experiment are feasible. |
| Cost of experiment | Comparatively less expensive. | Very expensive as it requires many basic chemicals, gels and even blotting paper. |
| Accuracy of detection | The sample detection is very accurate and even the quantity can be clearly known. | Though accurate, quantity can not be clearly known. |
| Technique of operation | It is very easy and simple that even a new experimenter can do with little guidance. | Very complicated and requires practice and standardization of the whole procedure. |
| Sensitivity is enhanced by | Washing and removal of unbound proteins. | Here other interfering proteins are removed by gel electrophoresis. |
| Types of experiments | ELISA is of different types like direct, indirect, sandwich type. | It is of different types like southern blot, western and even northern blot. |
| Pictorial demonstration | ELISA is just based on readings by electronic instruments. So it gives only result but no picture | This is based on physical appearance so enables to take photos and depict the result in presentations and publications. |
| Application | Mostly in health care for diagnosis and also in research. | Mostly in research but less preferred in health care due to time span. |
| Age of the technique | It is newer technique | Older technique. |
It appears that those who need a pictorial demonstration for publications and presentations for the western blot technique. Simultaneously, those who need just an accurate result like in health care go for ELISA.
In health care, the ELISA method identifies many diseases like AIDS, Hepatitis and other infections by just taking serum samples. It is also widely used in research as it is less time consuming and easy to perform.
On the other hand, the Western blotting test may be used as a confirmatory test for HIV after ELISA to avoid false positives.
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