ABC Medical Center > Procedures > PCR Test

What is pcr test?

10 November 2025

Index

Content

Contáctanos

PCR tests, or polymerase chain reaction tests, are a set of fast and reliable diagnostic studies used to detect genetic abnormalities, infectious diseases, and cancerous cells that cannot be found with other types of tests.

What Is PCR?

Through copies, PCR identifies the DNA and RNA of a virus or infectious agent, as well as any cellular abnormality present in the analyzed sample.

They gained great importance during the COVID-19 pandemic, as they are a fast and accurate way to know if there is an infection. Diseases like HPV, tuberculosis, HIV, hepatitis B and C, meningitis, or gonorrhea are conditions in which a PCR test helps with diagnosis.

One of the great advantages of PCR tests is that they can find diseases in their initial stage, which allows for timely treatment, unlike other types of tests that cannot identify diseases until they are already in more advanced stages and there are enough antibodies to be detected.

The procedure for a PCR test is as follows:

  1. A sample of a tissue or body fluid, such as blood, saliva, or mucus, is extracted.
  2. When placed in specialized equipment, the enzyme called polymerase is added to the sample to create copies.
  3. In a short time, millions of copies are produced in which, if any pathogen or cancerous cells exist, they are detected by the equipment.

In the case of COVID-19 and some other viruses, since they do not have DNA but RNA, a conversion to DNA is required so that they can be copied. This uses a reverse transcription PCR test.

How Is a PCR Test Done?

There are different ways to take samples for PCR tests.

Through a blood draw, a sample is taken from a vein in the arm and often helps detect HIV or hepatitis.

There are also three types of swabs, depending on the area where the sample will be taken:

  • Nasal swab (external nostrils): A swab is inserted and rotated in the nostril for 12 seconds. The swab is removed, and the procedure is repeated in the other nostril. This is for the rapid diagnosis of COVID-19 or detection of influenza.
  • Mid-turbinate swab: A swab is inserted to the back of the nostril and rotated for 12 seconds. The swab is removed, and the procedure is repeated in the other nostril. This is for the diagnosis of respiratory syncytial virus in children, as well as the identification of the type of influenza (A or B).
  • Nasopharyngeal swab: A swab is inserted into the nostril until it reaches the upper part of the throat. It is rotated for 12 seconds. This is a highly sensitive test for COVID-19 or the detection of respiratory adenoviruses and rhinoviruses.

Risks of a PCR Test

There are practically no risks in PCR tests, since a blood draw can only cause minor bleeding or a temporary bruise.

In the case of a nasal swab, it can cause discomfort like coughing, nausea, or a sore throat, symptoms that disappear immediately after the sample collection.

PCR tests have become a highly effective tool for controlling the spread of diseases. They allow for timely and early diagnoses that help treat diseases when they have not yet developed, which aids in patient recovery.

At the Clinical Analysis Laboratory at ABC Medical Center, we can provide you with specialized care. Contact us!

Fuentes

How can we help you?

    Ricardo Ostos

    Ricardo Ostos

    Content Creator

    Ricardo can convey complex medical information in an accessible and friendly way so that all of our patients can understand and benefit from it. In addition, he has an empathetic approach, offering information and practical advice that really makes a difference in people's lives. #lifebringsustogether.

    Learn more about Ricardo on LinkedIn

    The dissemination of the content of this material is for informational purposes only and does not replace, under any circumstance or condition, a consultation with a specialist doctor, for which the ABC Medical Center is not responsible for the different use that may be given to it. If you require more information related to the subject, we suggest you contact the specialist doctor you trust directly.