The ELISA Test: What It's For, When It's Necessary?

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Whether you suspect pregnancy or your doctor suspects early-stage cancer during your routine gynecological test, chances are they will recommend you for the ELISA test. ELISA tests are used across several biomedical research and discovery areas and for diagnostic purposes. As its widespread use suggests, there are several ways to do an ELISA test. 

 

By Jessica Smith 

 

Hence, determining which ELISA test is suitable for addressing your specific research question is critical. The choice depends on several factors, including the desired sensitivity or precisely what is being detected.

This article explores the use of ELISA tests and what to consider before choosing an ELISA technique.

What is the ELISA Test?

ELISA stands for enzyme-linked immunosorbent assay. It is a commonly performed laboratory test on a urine or blood sample utilizing the antibody specificity and the sensitivity of enzyme assays. This technique helps detect and quantify biomolecules such as proteins, antibodies, peptides, and hormones.

 

The ELISA test was first described by Engvall and Perlmann in 1971 and used to see immunoglobulin G. Before this technique, radioimmunoassay was done using the radioactively labeled antibodies and antigens.

 

Today, ELISA refers to a wide range of immunoassays, many of which do not involve enzymatic reactions. However, the common thing among all the ELISAs is the use of antibodies, which play a significant role in determining the sensitivity and specificity of the assay.

 

There are four methods to perform the ELISA test

·         Double Antibody Sandwich ELISA

·         Indirect ELISA

·         Direct ELISA

·         Competitive ELISA

 

Depending on the test type and sample required, numerous drug discovery products provider offer an extensive list of Elisa Kits to choose from. Some of these kits also feature reduced experimental time, pre-diluted detection reagents, and greater stability, finding various applications in different areas, including forensic, food, and clinical research.

 

1.      ELISA Test for Cancer Screening

 

Early-stage cancers like breast and ovarian cancer can be clinically tested using ELISA-based techniques. Identification and the measurement of cancer or tumor biomarkers detected in the body in response to cancer growth and development are possible by the ELISA test.

In recent years, clinical researchers have identified several established tumor protein markers associated with specific types of cancer, such as carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), and anaplastic lymphoma receptor tyrosine kinase (ALK), and many others. These markers are used clinically to determine cancer aggressiveness and monitor the disease's response to different treatments.

2.      ELISA Test and Drug Testing

 

Using ELISA, the patient's urine sample can be tested for concentrations of the most familiar illegal drugs, such as cannabinoids, amphetamines, cocaine, opiates, benzodiazepines, and methadone. Not only them, but healthcare providers can also use ELISA kits to monitor some pharmaceutical drug concentrations in patients undergoing treatment. For example, the antidrug antibodies in patients suffering from inflammatory bowel disease and rheumatoid arthritis.

3.      ELISA Kits for Testing for Pregnancy

 

To test for pregnancy, the doctors usually check for elevated levels of human chorionic gonadotropin (hCG) hormone in the patient's urine sample. ELISA test is performed to detect this hormone higher in pregnant women. Thus, women can quickly check their pregnancy at home using ELISA kits.

4.      ELISA and Detection of Viral Infections

 

In several developing countries with high rates of viral infections, ELISA testing can help detect viruses such as New Castle Disease Virus (NDV), HIV, and West Nile Virus. ELISA kits can be used for testing, like at the Emergency Department, and reach the most vulnerable groups because of their on-site testing abilities and immediate results.

For positive HIV infection, the ELISA test can detect human serum Cystatin C. The patient serum or cerebrospinal fluid sample collected after 8-21 days of having symptoms is tested by IgM antibody capture (MAC) ELISA.

 

Besides, this test also helps confirm whether the West Nile Virus disease has progressed to the patient's central nervous system. ELISA can even help identify any NDV-infected flocks, ranging from the most lethal to increasingly less severe strains, and aid in coordinating vaccination programs for people suffering from this avian viral infection.

 

5.      Other Uses

 

ELISA kits are famous worldwide for their simplicity, specificity, and cost-effectiveness. Many commercial and pharmaceutical outlets use ELISA kits for various analytes based on their popularity. It is one of the most popular kits used for pregnancy testing and is often preferred because of its high specificity and sensitivity.

In addition, ELISA offers more accuracy than other techniques, such as radioimmunoassay (RIA) tests.

Bottom Line

 

ELISA is a widely used effective technique in microbiology and virology. It is used for investigating infectious pathogens. However, several factors determine which ELISA technique is appropriate for addressing your requirement. Nonetheless, an ELISA test is quick and easy and is usually the first step of the diagnosis process. If your ELISA test is positive, your doctor may ask you to take further tests to confirm the diagnosis. If it is negative, you may have to repeat the test in a few weeks in case of a false negative result.

Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)