The price of the ELISA test for individuals is 55 euros per person from Monday to Friday and €5 more on weekends and holidays, the price of PCR test is 110 euros (Monday to Friday, weekend or holiday supplement +€15) and the antigen test is 50 euros. The tests can be carried out in Madrid, in our clinic at Paseo del General Martínez Campos number 46.

When a person decides to take a COVID-19 test, especially if they have recently been in contact with someone infected, it is advisable to carry out both types of tests, PCR and another serology test, either the ELISA test or the rapid test. The combination of these two types of tests will tell us what phase of the infection we are in: in the first 2 weeks after infection, the PCR test will be positive and the serology will be negative; later, it will be the other way around: the serologies will be positive and the PCR test negative.

The results of the ELISA test are delivered on Fridays from 8:00 p.m. and will arrive by e-mail.

Immunoglobulins A (IgA) are the first to appear, 4-5 days after infection and are one of the body’s main antibodies and are found both in the mucous membranes of the respiratory tract and the digestive system and in saliva, in tears and breast milk.

Immunoglobulins M (IgM) are the following antibodies that our body makes to fight an infection, they are detected around 10-15 days and are found mainly in the blood and lymphatic fluid. A positive IgM against SARS-Cov-2 would indicate that we are probably going through the acute or central stage of the infection.

Immunoglobulins G (IgG) are the most frequent antibodies in our body, they are detectable after 15-20 days and are found in the blood and other fluids. They provide protection against bacterial and viral infections and take time to form after an infection or after receiving a vaccine. A positive in IgG against SARS-Cov-2 would indicate that we have completed the last stage of a viral infection and that we are in the resolution phase.

Very high percentages in these two metrics are mandatory to be able to trust their results. Our laboratory performs the most complete test, which quantifies and measures the 3 types of IgA, IgM and IgG antibodies, using S (spike) and N (nucleocapsid) protein antigens to improve the sensitivity, specificity and robustness of the assay.

Sensitivity is the ability of the test to detect disease. It is calculated as the percentage of true positives over the total number of patients. For example, a sensitivity of 98% means that only 2 out of 100 samples have been diagnosed as negative (healthy) when, in fact, they were from infected individuals (positive). That 2% indicates the percentage of so-called false negatives.

Specificity is the ability of the test to detect healthy individuals. It is calculated as the percentage of true negatives over the total number of healthy individuals. For example, a sensitivity of 99% means that only 1 in 100 samples have been diagnosed as positive (infected) when, in fact, they were from healthy individuals (negative). That 1% indicates the percentage of so-called false positives.

In addition to knowing if we have (or not) IgA, IgM and IgG antibodies against SARS-CoV-2, this test will measure the amount of antibodies in the blood sample, also known as the count.

Antibodies, also known as immunoglobulins and abbreviated with the acronym “Ig”, are glycoproteins of the gamma globulin type or better said, and to understand us, antibodies are defense proteins that the immune system manufactures and are used to identify and combat foreign elements such as such as viruses, bacteria and toxins.

IgA and IgM appear first, but it is the presence of IgG antibodies against the virus, which appear approximately from day 15 from the start of the infection, which provide probable immunity. Although it is currently unknown for how long, it is usual that over the months or years, depending on the case, the IgG antibodies weaken until they disappear or cease to be effective.

From the acronym Enzyme Linked Immuno Sorbent Assay, which means “enzyme-linked immunosorbent assay”,the ELISA test is a quantitative test that indicates the amount of antibodies, or immunoglobulins, that we have in the blood against a virus. In this case, against the SARS-CoV-2 coronavirus. This laboratory test is also one of the most used to detect patients who have been infected with HIV.

The test only consists of a small blood draw (4 milliliters) and it is not necessary to come on an empty stomach.