ELISA test – what is it, when to do it, how much does it cost?

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The ELISA test is used in the case of bacterial, viral and parasitic infections. However, it is most often used in the diagnosis of Lyme disease. The ELISA test is quantitative – it detects the presence and number of antibodies. In order to find out the source of the infection, the Western Blot test should be repeated.

ELISA test – what is it?

The ELISA test, like the Western Bolt test, is a serological test. It is used to detect the presence of antibodies in the serum taken from the patient, which appear as a result of contact with the pathogen.

The ELISA test stands for the English sounding name enzyme-linked immunosorbent assay. In Poland, it is often called an enzyme-linked immunosorbent test or an enzyme-linked immunosorbent test. Interestingly, the ELISA test was developed in the 60s simultaneously by two independent research teams – Dutch scientists Baukea van Weemen and Anton Schuurs as well as Peter Perlmann and Evaa Engvall associated with the University of Stockholm.

The discovery of the ELISA test in the two cases was different, but led to a common feature of the use of enzymes that react with antigens characterized by specific antibodies. Initially, the ELISA test was only used to detect antibodies by testing the serum. However, it soon turned out to be an appropriate tool to analyze the amount of antigens in a given sample. The effectiveness of the ELISA test made it a strong competition for radioimmunological tests that were common at that time, but were dangerous to health.

The versatility of the ELISA test allows it to be used not only in biomedicine, but also in toxicology, agriculture and the food industry as an allergen detector.

ELISA test – what is it?

The ELISA test involves introducing the patient’s serum, potentially containing antibodies, into test tubes with specific bacteria.

Technically, the ELISA test is performed on polystyrene or plexiglass plates. Each has 96 wells in 8 rows and 12 columns. Separately analyzed samples are located in individual wells. During the ELISA test, the plate is coated with the appropriate antibody or antigen. Additionally, skim milk or ovalbumin solution is used to avoid non-selective binding of proteins to the phase during the subsequent test steps.

The reactions of enzymes with antibodies are visible due to the color appearing. The enzymes most often used in the ELISA test are:

1. alkaline phosphatase – stains yellow, transforming p-nitrophenol phosphate into p-nistrophenol,
2. glucose oxidase – causes a brown color in contact with 5-aminosalicylic acid,
3. horseradish peroxidase – gives a blue color after contact with tetramethylbenzidine.

In the ELISA test, the color change is analyzed by spectrometry, i.e. by measuring the light transmission through the sample. Then it is compared to the control samples in the form of a dozen or so solutions with known dilutions, which are also placed on the plate and subjected to the same treatments.

ELISA test – types

There are several variations of the ELISA test, including:

1. direct ELISA test – a simple and fast method, but expensive and not always possible, it consists in coating the substrate with an antigen and incubating it with a solution of a specific antibody combined with an appropriate enzyme; the protein content in the sample is estimated on the basis of the intensity of the color obtained after adding the appropriate substrate,
2. indirect ELISA test – the type of test most often used, which does not require labeling of the primary antigen-specific antibodies; during the test, the plate is coated with the antigen, followed by incubation with a solution of unlabeled primary antibody that binds only to the protein tested; the indirect ELISA test will give a color only after contacting the resulting complex with the secondary antibody,
3. sandwich ELISA test, i.e. double bind test or sandwich test; consists in coating the tested protein with specific antibodies, incubation with the antigen, and then with a specific immunoglobulin solution; the name of this type of ELISA test comes from the sandwich structure formed by both antibodies with the protein fragments with which they are related; a color reaction occurs after incubation with a secondary antibody labeled with an adequate enzyme solution, although it is also possible to use a primary antibody,
4. competition ELISA test – it consists in competition of a certain number of different antibodies condensed in a mixture for specific binding sites on the antigen; it is carried out by coating the solid phase with the appropriate protein, and then adding the analyzed serum and labeled antibodies; The intensity of the reaction and the associated color for this ELISA is inversely proportional to the concentration of the serum immunoglobulins.

ELISA test – diagnostics

What does an ELISA test diagnose? Due to the fact that it is cheap, fast and extremely sensitive, it is widely used, primarily in biomedicine. It is used to detect bacterial and viral diseases. The ELISA test is used to diagnose infections caused by:

1. toxins of enteropathogenic strains of E. coli bacteria,
2. cholera toxins,
3. rotawirusami,
4. hepatitis virus (types B and C),
5. certain flu viruses
6. HIV,
7. pale spirochete (infection causes syphilis)
8. Yersinia bacteria,
9. salmonella,
10. Helicobacter pylori bacteria,
11. golden staphylococcus.

In addition, the ELISA test is used to detect antibodies to amoebiasis, yeast, toxoplasmosis and malaria, as well as autoimmune diseases, including certain cancers or rheumatoid arthritis.

Also read: “Tests That Help Detect Cancer Early”

Test ELISA – lamblia i lamblioza

The ELISA test is used to diagnose not only infections but also parasitic diseases. These include giardiasis caused by the presence of lamblia, a dangerous parasite that colonizes the small intestine, duodenum and bile ducts. The ELISA test allows you to detect them after the first test.

Lamblia cysts are periodically excreted in the faeces and it is the material under study. Contrary to microscopic analysis of cysts, the ELISA test allows for quick detection of contamination based on the presence of antibodies.

ELISA test – Lyme disease

It is a tick-borne disease and the ELISA test is the oldest and most popular method of diagnosing it. Untreated Lyme disease can lead to serious complications, including diseases of the nervous system, joints, heart, encephalitis, or meningitis. The availability and ease of performing the ELISA test allows you to quickly detect the presence of Borrelia in the body and counter its effects.

In the case of Lyme disease, venous blood or cerebrospinal fluid is collected for the ELISA test. The test is to detect specific antibodies to the Borrelia spirochete – IgM, indicating the current infection, or IgG, which give information about the past infection. Western Bolt test is recommended in case of a positive ELISA result or in doubt.

Read also: «Lyme disease is becoming more and more common in Poland. 10 years ago there were not so many cases of disease »

ELISA test – indications

The ELISA test should be used if there is a suspicion of the presence of bacteria, viruses or parasites recognized during the test in the body. The most common symptoms include nausea, vomiting and increased body temperature.

When diagnosed with the ELISA test of Lyme disease, the symptoms are:

1. migrating erythema, i.e. red papules or spots with a bright center,
2. myocarditis,
3. arthritis – knee or ankle,
4. skin lymphocytic lymphomas – blue-red nodules appearing on the scrotum, nipple or auricle,
5. neuroborreliosis associated with inflammation of the meninges, peripheral nerves, or cranial nerves.

ELISA test – stages

The effectiveness of the ELISA test for Lyme disease is 70%. Therefore, the laboratory test is performed in two stages:

1. the first stage is an ELISA test in the IgM and IgG class,
2. the second stage is the Western Bolt test or the PCR method in the IgM and IgG class.

ELISA test – results

The ELISA test standards are as follows:

1. < 9 days BBU/ml - ujemny,
2. 9,1 – 10,9 units BBU / ml – doubtfully positive,
3. 11 — 20 – Eq. BBU/ml — low additional,
4. 21 – 30 units BBU / ml – highly positive,
5. > 30 units BBU / ml – very highly positive.

When interpreting the ELISA test results in Lyme disease, positive and negative results are possible:

1. negative ELISA test result – excludes the patient from further diagnosis for Lyme disease, indicates that the level of the presence of antibodies is zero or has not exceeded the acceptable standard,
2. false negative ELISA test – antibodies may not be detected if the test is performed too early; cross-reactivity may occur when other infections are detected by the ELISA test; it is possible for a patient to develop active Lyme disease without the presence of antibodies,
3. positive ELISA test result – means that antibodies have been detected in an amount exceeding the acceptable standard, but the detection spectrum does not indicate specific sources; the test must be confirmed by Western Blot to show what caused the infection,
4. False positive ELISA test – this is possible when the patient has isolated IgM antibodies.

ELISA test – price

How much does an ELISA test cost? The cost of testing for Borrelia’s presence depends on whether IgM and IgG antibodies are tested together or separately. In the first case, the price of the test will be PLN 45, in the second case PLN 60. On the other hand, the ELISA test for lamblia costs from 20 to 30 zlotys. If the patient has been referred for an ELISA test by a health insurance doctor and has received a referral, the test will be reimbursed by the National Health Fund, and therefore free of charge. The waiting time for ELISA results is 2 to 7 working days.

ELISA test – fasting?

In most cases, the ELISA test is performed with blood, so you should come to the test on an empty stomach, preferably in the morning, well rested and well-rested. It is imperative that you consult your doctor about any medications you are taking to determine their effect on the ELISA results.

We also recommend Shipment PCR test for Lyme disease and co-infections (tick test), so you can check if the tick that bitten you could be a carrier of the Lyme disease virus.