ELISA Test: History, Types and Kits

What is ELISA Test

ELISA is the abbreviation of the enzyme-linked immunosorbent assay. Sometimes, you would see another terminology EIA (enzyme immunoassay) instead of  ELISA, they both represent the same meaning. It is firstly used in detecting autoimmune related antibodies in patients with autoimmune disease. With the help of linked enzyme, the reactions between antigens and antibodies could be showed in a particular color.  That is why it is named “enzyme-linked immunosorbent assay ”, because ELISA test is related to “immune” and “enzyme”.

But  as we can see, ELISA tests are not only used in antigen/antibody detection fields with its development, and some ELISA tests use other signal amplifying methods instead of enzyme” We still like to call those not related to “immune” or “enzyme tests as ELISA. Meanwhile, if  we prefer to keep using this terminology, we should expand the definition of ELISA..

We can define  the ELISA test by the following sentence, “In a ELISA test, ligand(s) conjugate with receptor(s) accomplished with a color alter which is detectable and measurable.” We use ligand and receptor to substitute antigen and antibody, as well as drop the enzyme related description, thus expand the range of the definition.

ELISA test is a typical “wet-laboratory” type test, though it uses a solid phase to detect the presence of the substance, the substance is usually in a liquid or wet sample. Generally the solid phase is a solid plate with 96 wells, while some ELISA tests are performed with 192 wells’ or 384 wells’ plate.

ELISA test has been wildly used in medical diagnostic. And, it has been used in detecting  plant diseases’ pathogen in plant research.  In addition, many industries, such as food industry, apply ELISA test in quality control and quality assurance process.



History of ELISA Test

From the late 1960s, ELISA tests play a role in diagnostic research over 50 years. The origin of ELISA was the idea of finding an alternative method to substitute radioimmunoassay (RIA) in immunoassay.  Before the invention of ELISA, RIA is the only method to conduct immunoassay. Actually, the invention of RIA was not much earlier than ELISA. The First paper introduced this technique was published in 1960 by Rosalyn Sussman Yalow and Solomon Berson.

However, the concerns of potential safety and health problems coming with the initiation of  RIA. Scientists proposed to find another labeling method to replace radioactive label.  Some of them came up with an idea to use enzyme labels in immunoassay. But, many thought it is impossible to link the enzyme, such as large molecule, to an antibody or antigen without affecting their bioactivity in conjugating reaction. Although met with skepticism and criticisms, Perlmann and Schuurs independently invented the method to prove the using of enzyme-linked immunoassay is feasible in 1966. And following in 1966-1970, other scientists continually polish and improve methods, including resolving two critical issues for ELISA, which are “reaction associated color changing” and “ removing non-specific conjugation”.

Finally in 1971, Peter Perlmann and Eva Engvall at Stockholm University in Sweden (Enzyme-linked immunosorbent assay (ELISA) quantitative assay of immunoglobulin G), and Anton Schuurs and Bauke van Weemen in the Netherlands (Immunoassay using antigen—enzyme conjugates)

independently published papers that systematically introducing EIA/ ELISA methods. ELISA tests developed rapidly in the 1970s and early 1980s, and revolute into commercial clinical used products what we use now.

In the above content, we have introduced the main history of ELISA. But the imaginations and insights from the other scientist also contributed to the ELISA test development. For example, the concept of immunoassay minaturisation is conceived in 1963 by J.G. Feinberg and A.W.Wheeler. They invented a “microspot” & cellulose acetate strips method to detect autoimmune antibody of thyroglobolin in patients. We can find the ideas and concept of today’s ELISA test plate from their devices.


Types of ELISA Test


1.Direct ELISA

Figure 1

We use Figure 1 as an example to show the principles of the direct ELISA.

(1). The plate surface is coated with the virus antigen.

(2). The enzyme-linked specific antibody interact with the antigen, and become a complex.

(3). Adding substrate, then it will react with the enzyme and induce a color change which is detectable.

Note: in this example, the antigen is the “ analyte”(what we want to detect), we use enzyme-linked antibody to detect the existence of the antigen. However, in some ELISA tests, the antibody is the analyte. In that situation, we use enzyme-linked antigen to detect antibody.


2. Indirect ELISA


Figure 2.

We use Figure 2 as an example to show the principles of the indirect ELISA.

(1). The antigen is coated on the plate surface.

(2). The capture antibody (first antibody) “capture” the antigen, and become a complex.

(3). The detector antibody, which is labeled, conjugate with the capture antibody, and become a larger complex. We can detect the label to indirectly detect the antigen.

Note:  the antigen is the analyte in this example, but in many situation the antibody is the analyte. So we should design a special antigen to “capture” the antibody and a specific detector antibody to interact with the antigen with another site rather than immunoactive site.(Figure 3)

Figure 3



3. Sandwish ELISA


Figure 4

We use Figure 4 as an example to show the principles of the Sandwish ELISA.

(1) The plate is coated with a capture antibody.

(2) Sample is added, the specific antigen (analyte) binds to the capture antibody.

(3) Then the detecting antibody is added, and it binds to the antigen.

(4) The enzyme-linked secondary antibody is added, and it binds to detecting antibody.

(5) Finally, we add substrate, and it react with the detecting antibody to induce the color changing.

Note: The antigen is the analyte in this example, in other situation antibody maybe the analyte.


4. Competitive ELISA

Figure 5

We use Figure 5 as an example to show the principles of the Competitive ELISA

(1) Incubate the Antibody with sample containing antigens we want to detect. And they become complex.

(2) The antibody-antigen complex is added to the micro-wells which are pre-coated with the antigen. So, the free antibody can binds to the antigen coated on the micro-wells. The antibody in the complex and the unbounded antibody can be removed with washing

(3) Then we add Enzyme linked secondary antibody which is specific to the primary antibody. Wash again.

(4) Finally we add substrate, which react with the enzyme to induce a color change. The higher the concentration of antigen in the sample, the weaker color will be displayed.

Note: Different to the other types of ELISA test, the less absorbance means higher analyte concentration in the sample.


ELISA Test Kits and Our products 

The most popular ELISA product is the ELISA kit. Usually, users only need to prepare the analyte sample for the experiments, all the other components, such as plates, antibodies or antigens, substrate solution, TMB solution, controls, calibrators and etc., are provided by the ELISA kit.

Our company, Diagnostic Automation/Cortez Inc., sells a very wide range of ELISA Kit. For example, our two major ELISA Kit products are Autoimmune Disease ELISA Kits and Infectious Disease ELISA Kits (Figure 6 and Figure 7). We supply hundreds kind of products for both United States and global customers, and we are in a good relationship with many customers for long years. Hope you can also find what you need from us!

      Figure 6 ENA Profile-6 ELISA Kit  

        Figure 7 Syphilis (TPA) IgG ELISA Kit


The Advantages Of ELISA Test And Its Application In Disease Viruses Diagnostic

What are the advantages of an ELISA test?

One of the greatest advantages of ELISA tests is the ability to obtain quick and accurate results.  All that is normally required is a simple blood sample that is obtained either through the arm or fingertip of a patient.  The fact that an ELISA kit can test not only for antibodies, but antigens as well, makes it a versatile tool for physicians, laboratories, and medical professionals all over the world.The ELISA tests have also found applications in the food industry in detecting food allergens, such as milk, peanuts, walnuts, almonds, and eggs.  ELISA tests can also be used in toxicology as a screen for certain classes of drugs.  Another advantage of using ELISA test kits is their high sensitivity.  ELISA Tests are favored over other testing options because not only are they more sensitive, but they are more cost effective.  Even more striking, is the applicability of the ELISA tests as convenient and easy-to-use HIV ELISA testing devices.


ELISA Tests and HIV ELISA Tests

Because ELISA tests can be performed to evaluate either the presence of antigen or the presence of antibody in a sample, it is a useful tool for determining serum antibody concentrations, such as with HIV ELISA tests.  The HIV ELISA test is usually the first one used to detect infection with HIV virus.  If antibodies to the HIV virus are present, or positive, the test is usually repeated to confirm the diagnosis.  If the ELISA test is negative, other tests are not usually needed.  The ELISA test generally has a low chance of having a false result after the first few weeks of HIV infection.  The specificity and high sensitivity of the HIV ELISA Test make it a widely acceptable kind of ELISA test since it is able to detect all the possible HIV infections.  The HIV ELISA Test was the first screening test widely used for the HIV virus because of its high sensitivity.  Use of the HIV ELISA test kit, in relation to HIV virus detection, can be intended both for screening of blood donors or as an aid for the diagnosis of clinical conditions related to infection with HIV virus.

ELISA Tests and Hepatitis ELISA Kits

Diagnostic Automation/Cortez Diagnostics, Inc. has, as part of its superior ELISA test kit product inventory, numerous Hepatitis C ELISA Test Kits, or HCV ELISA Test Kits and Hepatitis B ELISA Test Kits, or HBV ELISA Test kits.  Simple to use Hepatitis C ELISA test kits include the HCV ab ELISA test which detects IgG antibodies to Hepatitis C virus in human serum or plasma.  The other convenient Hepatitis C ELISA test is the HCV ELISA Kit for quantitative detection of IgM class antibodies to Hepatitis C virus.  Also available are Hepatitis C Rapid Test Kits.

Superior and inexpensive Hepatitis B ELISA Kits are distributed within several ELISA Kit product categories: HbeAb ELISA Test Kit, HbeAg ELISA Test Kit, HbcAb Igm ELISA Test Kit, HbsAb ELISA Test Kit, and the HBsAg ELISA Test Kit.  All of these highly effective Hepatitis B ELISA Test Kits are available in any quantity worldwide.  Also in inventory and ready to ship, are top quality Hepatitis B Rapid Tests.

Other Hepatitis ELISA Tests Kits include:  HTLV ELISA test kit, HAV IgG ELISA test kit, HGV ELISA Test Kit, HEV ELISA Test Kit, HDV ELISA Test Kit, and HAV ELISA Test Kit.  Again, various simple and highly effective Hepatitis Rapid Tests are available worldwide.


Related Products


Los Angeles-based Diagnostic Automation/Cortez Diagnostics, Inc. has established the gold standard in its superior product line of ELISA Test Kits and HIV ELISA Tests.  A wide range of easy-to-use and inexpensive ELISA Test Kits are available:  Food Allergen ELISA Kits,Autoimmune ELISA Test Kits, Blood Bank ELISA kits, Cancer ELISA Test kits, Parasitology ELISA Kits, Steroid ELISA test kits, Thyroid ELISA test kits, Veterinary ELISA test kits, and Infectious Disease ELISA Kits, including Hepatitis ELISA Kits, HCV ELISA Kits, and HIV ELISA Test Kits.  For more information about these ELISA Test Kits, or other products such as Rapid Tests, IFA Tests, CIA Tests, Serology Tests, or any Drug Test Kits, please contact our Customer Service Department.

Some Related ELISA Kits Product Picture

                              HBcAb ELISA Kit


Elisa kits, Aflatoxin-B1

Workplace Alcohol Testing

team-spirit-959269_1280An employee who comes to work under the influence of drugs or alcohol will, at the very least, have diminished productivity and poor work performance; at worst, that person poses a serious safety risk to themselves and those around them. As an employer, you have both the right and the obligation to maintain a safe work environment for fellow employees, which is why insisting on a drug- and alcohol-free workplace is necessary.

A urine alcohol rapid test, as well as a saliva alcohol test, are both reliable ways for employers to immediately determine if alcohol is present in the blood. Whether you suspect an employee to be under the influence, or you administer random drug and alcohol screenings to your employees, you can trust the results from our urine alcohol rapid test kits.

The urine alcohol test kit is intended for the screening of ethyl alcohol in human urine. MP Rapid Alcohol Test is designed as the screen tool to rapidly determine if the BAC level is higher than 0.04% (the cutoff level at which an individual is considered positive for the presence of alcohol) by testing the urine specimen. The distinct color on reactive pad could be observed in less than 4 minutes after the tip was contacted with urine samples with the ethyl alcohol concentration greater than 0.04%.

While follow-up tests are nearly always necessary in order to confirm the initial results, urine tests, such as the options from Diagnostic Automation / Cortez Diagnostics, Inc., can provide immediate data.

Detecting Pregnancy with HCG

woman-1209322_1920When you’re actively trying to get pregnant you’re eager to take a pregnancy test as soon as possible in order to confirm what you’ve been hoping for – a baby! But have you ever wondered just what a home or doctor administered pregnancy test is looking for? That red or blue line, plus or minus symbol indicator holds a lot of hopes and dreams, but here’s what it’s really telling you.

What that little stick is checking for is HCG – human chorionic gonadotropin. The hormone HCG is produced in the earliest stages of pregnancy. HCG is made by the placenta during pregnancy. Levels of HCG rise rapidly in the earliest days of pregnancy and usually first appears in urine 9-10 days following the estimated day of conception when using the most sensitive HCG Rapid Test.

HCG helps to maintain your pregnancy and affects the development of your baby. Levels of HCG increase steadily in the first 14 to 16 weeks following your last menstrual period, peak around the 14th week following that date, and then decrease gradually. The amount that HCG increases early in pregnancy can give information about your pregnancy and the health of your baby.

Results from the test can also help determine and monitor an abnormality of the pregnancy. For example, low HCG levels during a pregnancy can suggest an ectopic pregnancy or even miscarriage. High HCG levels can indicate twins or triplets. Not all pregnant women who test before the day of their expected period will obtain a ‘pregnant’ result. This is because urinary HCG levels may not yet be above the threshold for the test.

Lyme Disease Symptoms & Prevention: Part II

rivers-258367_1920Perhaps the most well-known symptom of Lyme disease is a rash that looks like a bull’s-eye. This occurs in 70-80 percent of people infected by a tick bite. The area directly around the tick bite may be red and raised and look like a normal bug bite. The rash often spreads in a circular pattern that’s lighter in the center and darker on the outer ring. However, not everyone who gets Lyme disease gets the target-shaped rash.

Classic signs of early Lyme disease include: muscle aches, headache, fatigue and fever. Some people with Lyme disease experience other, more advanced symptoms of the illness. Joint pain, especially in the knees, and a stiff neck may occur in the early-symptom stage or several months after your tick bite. Severe headaches and shooting pain in your body can occur. Dizziness and changes in your heart rate or rhythm are also advanced symptoms of Lyme disease.

Lyme disease is treated with antibiotics. The earlier you’re treated, the better your chances for recovery. Most people who are diagnosed in the early stages take an oral medication for between two and three weeks.

Ultimately, it’s best to avoid and prevent infection, obviously. While we don’t want to limit time outdoors, it’s imperative to use caution and follow these guidelines to reduce your chances of a tick bite:

-Use DEET on skin and treat clothing with spray containing permethrin.
-Avoid tick-infested areas, such as dense leaves under trees.
– Avoid brushing against long grasses and brush on edges of paths. Don’t sit on stumps or fallen logs.
-Wear light-colored long pants and long sleeves so you can easily see any ticks.
-Tuck shirt into pants and tuck pants into socks.
-Do a thorough tick check upon returning inside and for several days following exposure.

Symptoms can start at any time between three and 30 days after infection. The incubation period can also lead to confusion about your symptoms. If you don’t remember being bitten, you may think you have the flu and you may not connect the tick bite and your symptoms.

If you’re experiencing any symptoms, contact your doctor immediately. They can administer a Lyme disease test kit, as well as blood work, to confirm or rule out Lyme disease infection.

Facts About Lyme Disease: Part I

tick-1271763_1280Most of us have at least heard about Lyme disease and know that it’s contracted from a tick – but that’s the extent of most people’s knowledge. In order to keep you and your family safe it’s important to know the details of Lyme disease, including what exactly it is, the symptoms and side effects , how to prevent Lyme disease and the use of Lyme Disease Elisa test kits in detection.

The Centers for Disease Control and Prevention estimate that 300,000 people are diagnosed with Lyme disease in the US every year. With the exception of winter, when many, but not all, ticks are dormant, it’s possible to come into contact with a tick from spring through fall. That’s why isn’t important to be knowledgeable and aware of the risks.

What is Lyme Disease?
Lyme disease is an illness that’s caused by bacteria carried by infected Ixodes ticks, also known as deer ticks, and on the West Coast, black-legged ticks. Ticks are typically found in wooded and grassy areas.

Lyme disease can affect any organ of the body, including the brain and nervous system, muscles and joints, and the heart. Lyme disease is treatable, but it can cause serious health problems if you wait too long to receive treatment. Many people with Lyme disease don’t know they have it until their symptoms are advanced. Knowing the signs and symptoms will help you to seek treatment as early as possible.

To learn more about Lyme disease, continue reading our next blog post, Lyme Disease Symptoms & Prevention: Part II.

How Does Zika Virus Spread?

mosquito-1465062_1920As if mosquito’s weren’t nuisance enough in late spring and through the summer season, we must now contend with the risk of contracting the Zika virus. Protection is key, especially for children and pregnant women, to prevent being bitten, as well as preventing the spread of the disease.

In our previous post, Facts about the Zika Virus, we discussed the threat of the virus, symptoms and prevention. Now let’s discuss how the disease spreads.

Mosquitoes can carry Zika from person to person. If a pregnant woman is infected, the Zika virus can be transmitted to her baby while she is pregnant or around the time of birth. Mosquitoes that spread Zika virus bite both indoors and outdoors, mostly during the daytime.

As the weather becomes warmer, more mosquito’s will circulate. Some of the mosquito’s can be infected with the Zika virus. It is imperative to protect yourself using bug sprays and repellents containing DEET (20% to 30% concentration is best, according to the CDC), picaridin, oil-of-lemon eucalyptus, para-menthane–diol or IR3535.

However, being bitten from an infected mosquito isn’t the only way to contract the virus. The virus can also be sexually transmitted, including through oral sex, which can be very dangerous for pregnant women, or those trying to become pregnant.

The Centers for Disease Control and Prevention (CDC) still is reviewing data on whether the virus can be transmitted through saliva and urine.

The best way to prevent becoming infected with the Zika virus is to wear long sleeves and pants, or clothes treated in permethrin, when necessary, use insect repellent and sleep in screened or air-conditioned rooms.

If you’re a doctor’s office, hospital, or emergency clinic looking for testing kits, RapidTest offers exceptional ELISA test kits, including infectious disease, parasitology, diabetes, and blood bank kits. Contact us today to learn more about our full selection of diagnostic test kits.

Facts about the Zika Virus

tiger-mosquito-49141_1920As the Zika virus continues to spread world wide – and with hundreds of imported cases here in the United States -here’s what every American needs to know about the virus and their risk.

With 40 million Americans traveling to Zika-affected countries every year, it’s only a matter of time before local transmission of the virus will begin, according to infectious-disease experts. It’s most likely to happen when an infected traveler returns to the U.S. and is bitten by a mosquito that’s capable of spreading disease.

Most people infected with Zika virus won’t even know they have the disease because they won’t have symptoms. The most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis (red eyes). Other common symptoms include muscle pain and headache.

If a pregnant woman is infected, the Zika virus can be transmitted to her baby while she is pregnant or around the time of birth. Some, but not all, babies born to mothers infected with Zika can have the birth defect, Microcephaly. Microcephaly is a condition where a baby’s head is much smaller than expected and can lead to a number of health-related issues.

Preventing mosquito bites is the best way to prevent Zika. If you’re in an area with disease-spreading mosquitoes, wear long-sleeved shirts and pants, no matter how warm it is. According to the CDC, use insect repellents that contain one of the following ingredients: DEET (20% to 30% concentration is best, according to the CDC), picaridin, oil-of-lemon eucalyptus, para-menthane–diol or IR3535

Vaccine development is under way at the National Institutes of Health (NIH). Scientists are tweaking a vaccine that was initially developed for the West Nile virus, and they expect to launch a safety trial for it in September 2016.

If you’re a doctor’s office, hospital, or emergency clinic looking for testing kits, RapidTest offers exceptional ELISA test kits, including infectious disease, parasitology, diabetes, and blood bank kits. Contact us today to learn more about our full selection of diagnostic test kits.

An abnormal Serology Test

medic-563425_1280Detection of antibodies from serological testing can be used to either diagnose an active or previous infection, or to determine if you are immune to reinfection by an organism. As the disease gets worse, more antibodies will be present. If a disease is suspected, the test may need to be repeated 10 days to 2 weeks after the first test.

If antibodies are found, you may:
Have a current infection.
Have been infected in the past.
Have immunity to a certain organism and are unlikely to become sick.

Some of the different diseases that can be detected include:
Human immunodeficiency virus (HIV)
Fungal infection
Viral hepatitis (various types)

Additional conditions under which the test may be performed:
Amebic liver abscess
Fifth disease
Fungal arthritis
Meningitis, cryptococcal
Meningitis, H. influenza
Meningitis, meningococcal
Viral arthritis

Making the right diagnoses to help your patients is simple when you are using serology tests and other supplies from Diagnostic Automation / Cortez Diagnostics, Inc. We offer great serological testing supplies for medical professionals throughout the world. When you need so choose serological testing supplies for your medical office, laboratory, or hospital, you can count on Diagnostic Automation / Cortez Diagnostics, Inc.

The Purpose of Serology Testing

laboratory-313867_1920A serology blood test is performed to detect and measure the levels of antibodies as a result of exposure to a particular bacteria or virus. When a person is exposed to bacteria or viruses (antigens), their body’s immune system produces specific antibodies against the organism. Antibody levels help physicians determine whether an infection occurred recently or years ago.

There are several types of serological tests that can effectively detect such antibodies. There are also several serology techniques that can be used depending on the antibodies being studied. These include: ELISA, agglutination, precipitation, complement-fixation, and fluorescent antibodies.

ELISA, or enzyme-linked immunosorbent assay, is a test that uses antibodies and color change to identify a substance. ELISA is a popular format of “wet-lab” type analytic biochemistry assay that uses a solid-phase enzyme immunoassay (EIA) to detect the presence of a substance, usually an antigen, in a liquid sample or wet sample.

Serological testing is particularly helpful in the diagnosis of viral diseases such influenza and measles, as well as of infectious diseases like mononucleosis and rheumatoid arthritis.

Provide effective serology tests to your patients when you choose tests from Diagnostic Automation/Cortez Diagnostics, Inc. Our business provides you with a huge array of diagnostic tests, including serological testing supplies used to detect Mononucleosis. If you have any questions about this or any of our other products, please feel free to call us at (818) 591-3030.