COVID-19 Testing: What You Have to Know
Types of COVID-19 Testing:
1. PCR or RT-PCR test: The most reliable test for people with or without symptoms. Polymerase chain reaction test needs sample collecting through the oral or nasal swab. It is most often performed in a laboratory.
2. Antigen test: Rapid test, can produce results in 15-30 minutes. Obtain a bodily fluid sample using a nasal swab and test if the result is positive. Less reliable than PCR-based tests.
PCR would be chosen where there is a low likelihood of having the virus, but we want to be certain the patient doesn't have it. Antigen tests would be chosen if there is a high probability the patient has the virus (i.e. is experiencing symptoms), and we need to screen the patient as positive or negative.
How to test if someone is infected with Coronavirus?
The best way to identify if someone is infected with coronavirus is the Nucleic acid test(NAT) or Nucleic acid amplification testing（NAAT) with a throat & nasal or nasopharyngeal swab sample. Nucleic acid testing is the early diagnosis of disease by detecting genetic material (DNA or RNA). PCR-based tests are NAATs. The test results will be got in the laboratory.
Or you can test by yourself at home using an antigen test. You would get the result rapidly, especially if you have had some symptoms.
How to correctly get the swab sample?
Swabbing is the first step of all the COVID-19 test methods. It is a new procedure for most front workers who are not familiar with or just get rapid on-the-job training. Not unfamiliar with nasal & oral anatomy and have no exercises before really collecting swab samples from patients.
However, as we know, improper swabbing has led to patient injury and false-negative results. Thus, appropriate swab training is essential for healthcare workers or medical personnel.
Get a swab training model and follow the appropriate operation to learn how to collect a swab sample correctly.
1. Proper sampling procedure of oropharyngeal swab
The correct execution of the oropharyngeal swab requires a selective sampling of the oropharyngeal mucosa of the posterior wall and base of the tongue.Step 1: The swab is inserted parallel to the lingual retractor toward the posterior wall.
Step 2: One lateral side of the oropharynx is swabbed, followed by the contralateral side, and finally, the base of the tongue is swabbed.
The patient is asked to breathe slowly and to focus the attention on breathing to reduce vagal stimulation.
While the oropharynx is not easily seen with mouth opening, a lingual retractor should be used.
2. Correct nasopharyngeal swab collectionStep 1: The patient is seated with the head tilted up 30–45° towards the operator performing the swab.
Step 2: The swab must be inserted at the inferomedial angle of the nostril, next to the nasal septum, proceeding along a plane parallel to the hard palate.
Step 3: When inserting the swab, its tip should point sideways, away from the nasal septum and towards the inferior turbinate.
The length of the nasal fossa corridor from the nostrils to the nasopharynx is between 9 and 12 cm.
It is important to check the length of swab insertion to be sure that the deepest target area has been reached.
Interpreting your COVID-19 test results
1. If your COVID-19 test is positive
Any positive COVID-19 test means the virus was detected and you have an infection.
2. If your COVID-19 test is negative
A negative COVID-19 test means the test did not detect the virus, but this doesn't rule out that you could have an infection.