Coronavirus Swab Test ? What would you think when we heard about a swab test? Painful Test? Scary one because your nose would be put into by a long stick? The more accurate result? Well, there are so many thoughts for sure running in our mind by seeing how the Swab Test (PCR) done.
A nasal (or nasopharyngeal) swab is used to diagnose upper respiratory tract infections, such as whooping cough and COVID-19. It is a quick test that may feel a little uncomfortable but should not be painful.1 Mainly based on typical symptoms, bilateral involvement on chest radiographs, and exposure to infected patients, and confirmed by positive nucleic acid test of SARS-CoV-2 from numerous types of specimens. Reverse-transcriptase-polymerase-chain-reaction (RT-PCR) is the most common method for SARS-CoV-2 detection by targeting the ORF1ab, N, or E genes. Oropharyngeal and nasopharyngeal swabs were most frequently used samples.3
Reverse Transcription-Polymerase Chain Reaction (RT-PCR). RT-PCR relies on its ability to amplify a tiny amount of viral genetic material in a sample and is considered to be the gold standard for identification of SARS-CoV-2 virus.4
Should we get covid-19 Test? Your health care provider will provide you guidance on the need for being tested for novel coronavirus (COVID-19). As the numbers of cases decline and testing become less challenging, public health officials will again try to contain the virus through contact tracing and early isolation. That will require appropriate testing of individuals who may be infected with coronavirus.
Currently, COVID-19 tests are prioritized for the following groups:
- Hospitalized and symptomatic individuals
- Health care workers
- First responders and other social service employees
- People exposed to infected individuals in places where COVID-19 risk is high
Asymptomatic (non-ill) residents or employees of group-living facilities, either after a positive case has been identified or before readmission5
The novel coronavirus swab testing specimens shall be collected by qualified technicians who have received biosafety training (who have passed the training) and are equipped with the corresponding laboratory skills.2
Testing for COVID-19 involves inserting a 6-inch long swab (like a long Q-tip) into the cavity between the nose and mouth (nasopharyngeal swab) for 15 seconds and rotating it several times. World Health Organization (WHO) recommends that providers use a sterile dacron or rayon swab with a flexible, plastic shaft for deep nasal sampling. Cotton, calcium alginate swabs, or swabs with wooden sticks may contain such compounds that can inactivate some viruses and inhibit the diagnostic polymerase chain reaction (PCR). The swabbing is then repeated on the other side of the nose to make sure enough material is collected. The coronavirus swab test is then inserted into a container and sent to a lab for testing.3,6
After that how they store this specimen and shipped to a laboratory?
WHO also wrote several trusted resources how the virus is stored and checked in the laboratory. Specimens for virus detection should reach the laboratory as soon as possible after collection. Correct handling of specimens during transportation is essential. Specimens that can be delivered promptly to the laboratory can be stored and shipped at 2-8°C for up to 72 hours after collection. When there is likely to be a delay in specimens reaching the laboratory, the use of viral transport medium is strongly recommended. Specimens may be frozen to – 20°C or ideally -70°C and shipped on dry ice if further delays are expected. It is important to avoid repeated freezing and thawing of specimens.7,8
So here’s the following protocol describes the proper procedure the patient get a nasopharyngeal swab sample for swab test (PCR) :
- The patient escort into the examination room area
- The patient will be explained the process and obtain their consent to process
- Provider open the swab package of a sterile swab and take out the swab
- The provider tilt the patient’s head back slightly (about 70o) to straighten the passage from the front of the nose to the nasopharynx. Instruct the patient to close his or her eyes, then gently insert the swab along the nasal septum until resistance. (see Figure 1).
- The coronavirus swab test rotates several times for 10-15 sec to collect the sample material.
- Remove swab and the sample insert into a collection vial containing 1 – 3 mL of viral transport media.
- The swab handle break at the marked breakpoint and close the vial.
- Label the vial with the following information: Collection date, Onset date, Patient age and sex, Specimen type (e.g.: nasal swab), Unique identifiers, Other pertinent information
- Repeat the same procedure with the other nostril.
- Follow the manufacturer’s instructions to store the sample and transport it to an FDA approved diagnostic laboratory.4
After that, the vial brings to the diagnostic laboratorium. Than labrorian will mix the sample with reagents. The process like in following figure 2.
- Step 1: At the 3′-end of the viral RNA, reverse transcriptase and BIP primer initiate conversion of RNA to cDNA.
- Step 2: At the same end, DNA polymerase and B3 primer continue to generate the second cDNA strand to displace and release the first cDNA strand.
- Step 3: The FIP primer binds to the released cDNA strand and DNA polymerase generates the complementary strand. Step 4: F3 primer binds to the 3′ end, and DNA polymerase then generates a new strand while displacing the old strand. LAMP cycling produces various sized double-stranded looped DNA structures containing alternately inverted repeats of the target sequence as detected by a DNA indicator dye. Reagents*: Primers and master mix containing reverse transcriptase, DNA polymerase with strand displacing activity, dNTPs, and buffers.
Although RT-PCR is the most widely used method for detecting SARS-CoV-2 infections, it has the disadvantage of requiring expensive laboratory instrumentation highly skilled laboratory personnel, and can take days to generate results. As a result, a number of companies and laboratories around the globe are working to further improve the efficiency and timeliness of the RT-PCR technologies and develop various other techniques.
In addition, a few studies have also been done using serum, stool, or ocular secretions.1 Recently, the Rutgers Clinical Genomics Laboratory developed an RT-PCR assay (TaqPath COVID-19 Combo kit) that uses self-collected saliva samples, which is quicker and less painful than other sample collection methods, lowers the risks to healthcare providers, and may enable higher volume testing.9,10
In Bali itself, the hospitals give various price to do this swab test. It is from 350K – 6000K in 24 hrs – 72 hrs
- Carter, L.J; Garner L.V., et al. Assay Techniques and Test Development for Covid-19 Diagnostic. ACS Cent. Sci. 2020, 6, 591-605
- Wang W, Xu Y, Gao R, et al. Detection of SARS-CoV-2 in different types of clinical specimens. JAMA. 2020, http://dx.doi.org/10.1001/jama.2020.3786.
- Petrova Elena V., Xu Huan, et al. COVID-19 / Coronavirus Outbreak: Performing a Nasal Swab Test on Patients inside a Rapidly Deployable Facility Optimized for Epidemics. Journal of Visualized Experiment. March 2020
- Rutgers University; New Rutgers Saliva Test for Coronavirus Gets FDA Approval: Emergency Use Authorization Granted for New Biomaterial Collection Approach. Rutgers Today, April 2020. www. rutgers.edu/news/new-rutgers-saliva-test-coronavirus-gets-fdaapproval.
- U.S. Food & Drug Administration. Accelerated emergency use authorization (EUA) summary SARS-CoV-2 ASSAY (Rutgers Clinical Genomics Laboratory). April 10, 2020, pp 1−8. www.fda. gov/media/136875/download.