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To push past the global pandemic, COVID-19 tests are essential because we can identify positive cases, treat those who are ill and stop the spread of the disease. While ramping up COVID-19 testing was a gradual process, now widespread testing and convenient at-home COVID-19 kits make tests accessible and convenient. Currently, the most common coronavirus testing method is through a process called reverse-transcriptase polymerase chain reaction (RT-PCR).
When you get a COVID-19 test a healthcare professional swabs your nose or throat to collect a sample of mucus. This specimen is placed in a vial and sent to a laboratory for testing. Keeping samples at the right temperature (between 35 and 40 degrees Fahrenheit), and ensuring that samples are processed within four days—otherwise they must be frozen or discarded—is critical for ensuring the integrity of the specimen. Otherwise, samples could produce inaccurate results.
In the lab, a technician will extract the RNA, using substances called reagents. Then, enzymes are added to complete the reverse-transcriptase process, through which the RNA is turned into DNA. Technicians add more reagents that copy the DNA, as well as fluorescent dyes that indicate the presence of COVID-19. The sample goes through a process of heating and cooling, known as polymerase chain reaction, in a special PCR machine. A light-measuring instrument in the PCR machine reads the fluorescent patterns in the sample, which indicates whether the sample does or does not contain the virus.
You could get results in minutes or days, depending on the type of COVID-19 test you take. Generally, the RT-PCR process takes a few hours to complete. However, in late March 2020, the Food and Drug Administration (FDA) approved a new method that shows positive results in five minutes, and negative results in 13 minutes. This method, which uses a platform called ID NOW, allows for samples to be tested on-site rather than being sent to a lab. In late May 2020, Abbott, the company that designed the ID NOW rapid test, released an interim analysis of an ongoing clinical study designed to assess the test’s accuracy, after initial reports of false-negatives.
The most common method of sample collection is a nasopharyngeal swab, in which a long Q-tip-like swab is inserted deep into the nasal passage. However, the FDA also allows short swabs for collecting samples from the front of nostrils. Samples also can be collected from an the throat.
If you have a productive cough, healthcare workers can collect a sample of phlegm to be tested, as the CDC recommends testing lower respiratory tract specimens when available. The CDC also suggests collecting a sample from the lower respiratory tract if you are receiving invasive mechanical respiration. Samples collected directly from a patient’s lungs could contain more evidence of the virus. The CDC does not recommend inducing phlegm to get a sample.
Labs are developing other methods of testing for COVID-19 to help fight this new coronavirus.
For example, at-home tests allow individuals to collect their own samples and mail or deliver them to labs for testing. These tests are ideal for individuals who are still under stay-at-home orders, and they alleviate some of the burden on healthcare workers. Not to mention, at-home COVID-19 tests are convenient and widely available with a prescription or over the counter from a pharmacy. The more people who get tested, the better we can control the spread of COVID-19.
Read more: At-home COVID-19 Testing
As the capacity for diagnostic testing for coronavirus has increased, the guidelines for when to get tested have relaxed somewhat. However, exactly who can get tested and what the steps are varies depending on where you live.
Currently, the CDC offers these guidelines for prioritizing who should be tested for the coronavirus:
If you think you have been exposed to COVID-19 or exhibit symptoms of the disease, you should contact your healthcare provider, or state or local health department for guidance on when and how to get tested.
Those experiencing any of the following symptoms of severe illness should seek medical attention and testing immediately:
If you are experiencing minor COVID-19 symptoms and are not over 65 or immunocompromised, contact your healthcare provider to find out if you should be tested for COVID-19. Your healthcare provider also can provide guidance for treating your symptoms with over-the-counter medications and self-isolation.
Read more: When to Get Tested for Coronavirus
|Centers for Disease Control and Prevention (CDC)||The CDC is the United States’ leading national public health organization. Its mission is to protect public health and safety through the control and prevention of disease, injury, and disability in the U.S. and abroad.|
|World Health Organization (WHO)||A specialized agency of the United Nations, WHO is responsible for international public health. Headquartered in Geneva, Switzerland, it has field offices worldwide.|
|Association of Public Health Laboratories (APHL)||The APHL is a nonprofit organization in the United States that represents laboratories that protect public health and safety.|
|State Departments of Health||Each state in the U.S. has its own department of health. These public health departments are currently coordinating efforts for COVID-19 testing and treatment.|