Rapid Antibody Test, Here's What You Should Know

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Rapid Antibody Test, Here's What You Should Know
Rapid Antibody Test, Here's What You Should Know

Rapid antibody test is an examination to quickly detect the presence of antibodies in the blood. The presence of antibodies in the blood can indicate a person has or is currently infected with a disease

When a virus or bacteria attacks the body, the immune system will respond by producing specific antibodies against these microorganisms. These antibodies will stick to the invading virus or bacteria and try to paralyze it.

Rapid Antibody Test, Here's What You Should Know - Alodokter

The purpose of the antibody rapid test is to detect the presence of specific antibodies in the blood that can fight certain diseases. For example, the rapid antibody test for COVID-19 aims to see if the patient's blood contains IgM and IgG antibodies that are specific for the Corona virus (SARS-CoV-2).

Indications of Rapid Antibody Test

As explained above, antibody rapid test is used to detect antibodies or also known as immunoglobulins. There are five types of antibodies that can be produced by the immune system when there is an attack of disease. The antibodies are:

  • Immunoglobulin A (IgA)
  • Immunoglobulin D (IgD)
  • Immunoglobulin E (IgE)
  • Immunoglobulin G (IgG)
  • Immunoglobulin M (IgM)

Of the five antibodies, antibody rapid tests generally detect immunoglobulin G (IgG) and immunoglobulin M (IgM). These two types of antibodies are formed when the body has an infection and are found in the blood.

IgM is an antibody that is produced earlier when there is an infection. IgG appears slower, but lasts longer and serves to ward off the same infection in the future.

By knowing the presence and measuring the levels of these antibodies, antibody rapid tests can help doctors in diagnosing various infectious diseases, such as:

  • Toxoplasmosis
  • Hepatitis B
  • dengue hemorrhagic fever
  • typhoid fever
  • Rubella
  • Cytomegalovirus
  • Herpes
  • COVID-19

In other words, doctors can conduct rapid antibody tests on patients who have symptoms or conditions that lead to the diagnosis of the diseases above, such as:

  • Fever that is difficult to determine the cause
  • Diarrhea that doesn't go away
  • Losing weight for no apparent reason
  • Easy to get tired
  • Nausea and vomiting
  • Muscle pain

The doctor's consideration of the patient's medical history, lifestyle, and activity patterns also plays a major role in determining whether the patient needs a rapid antibody test or not.

Antibody Rapid Test Alert

It should be underlined, the antibody rapid test aims to detect antibodies produced by the body to fight infection, not the microorganisms that cause the infection itself. Therefore, the antibody rapid test is usually only done as an initial examination (screening).

To confirm the diagnosis of a disease, the doctor will perform other supporting examinations, such as:

  • Complete blood count
  • Blood protein test
  • Urine sample test
  • Polymerase chain reaction (PCR)
  • Rapid test antigen

Before Antibody Rapid Test

There is no special preparation that must be done before undergoing a rapid antibody test. However, it is recommended that you provide your medical history and any medications you are currently taking, as some medications can affect test results.

Antibody Rapid Test Procedure

Rapid antibody test is done by taking a blood sample from the fingertip (finger prick). The following are the steps taken by doctors in the process of taking blood samples:

  • Cleaning the patient's fingertips with alcohol
  • Inserting a needle into the patient's fingertip to remove a blood sample
  • Drop a blood sample into the rapid test tool
  • Drip antibody detecting fluid onto the rapid test device that previously had a patient's blood sample dripped on it

After Antibody Rapid Test

The results of the antibody rapid test can be immediately known on the same day. For example, in the rapid antibody test for COVID-19, the results can come out in just 15 minutes. These results are listed on the test kit in the form of a line in the IgM or IgG column.

Rapid test results can be positive (reactive) or negative (nonreactive). Here are the details:

  • A positive IgM and a positive IgG indicate an active infection, estimated to occur about 3 weeks before the test.
  • Positive IgM and negative IgG indicate an active infection, estimated to occur 1–3 weeks before the test.
  • Negative IgM and positive IgG indicate an inactive infection, estimated to have occurred more than 3 weeks before the test.
  • Negative IgM and negative IgG can mean the patient is not infected or has been infected but antibodies have not been formed.

It is important to remember that rapid antibody tests cannot be relied upon to confirm the diagnosis of a disease. This is because there is a possibility of false positive or false negative rapid test results.

A false positive result means that the rapid test result for antibodies to a disease shows a positive result, even though the patient does not actually have the disease. While a false negative result is the opposite, showing negative when it is actually positive.

Let's see an example of the COVID-19 rapid test. A false negative result means that someone who should have tested positive for COVID-19 got a negative rapid test result. If this test is used as a reference for diagnosis, the person will feel no need to self-isolate. This poses a risk of harm to those around him.

Side Effects of Antibody Rapid Test

Rapid antibody test does not cause harmful side effects. The patient may experience some pain when the needle is inserted to collect a blood sample, but the pain will soon go away.

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