India, today, stands at number third amongst the worst-affected countries by COVID-19, with over 5 Lac active cases. The Health Ministry of India has introduced multiple diagnostic tests since the onset of the Pandemic, some of which are the RT-PCR, Rapid Antibody Test, Pooling Tests, Rapid Antigen Test, etc.
The indispensable need for Testing
Survey says that with adequate testing, two people that have been infected and diagnosed properly can be isolated in quarantine, and can spread the virus to only about five people. Whereas, with a lack of testing, two people who are infected and yet not diagnosed have the potential to spread the infection to a maximum of 800 people. Thus, timely testing reduces the probability of spreading the virus to less than 1% of what the probability is if not tested.
The Indian Government followed a triple strategy of ‘ test,track and treat to prevent the spread of infection and save lives. Aarogya Setu aims to determine whether you are at risk of exposure by assessing your location and scanning its database of known cases in India.
Testing is the key to controlling viruses.The WHO sent a clear message to all countries in mid-March: test,test and test. More the number of tests conducted, the easier it is to track the spread of the virus and therefore reduce transmission.
Who should opt for testing:
1. All migrant workers and those having possible International travel history in the past 14 days will have to undergo a COVID test and receive necessary quarantine.All passengers shall be advised to download Arogya Setu app on their mobile device to track the status.
2. Any asymptomatic and high-risk patients, especially those with contact history to other positive patients. As per new guidelines, atypical and high-risk contact cases should be tested between 5 and 10 days of coming into contact with the positive patient.
3. Any Individual who is at a risk for developing Influenza-like illness , related symptoms will also be tested for possible Coronavirus symptoms.
COVID-Tests Types conducted in India
1. RT-PCR Tests
The reverse transcription-polymerase chain reaction (RT-PCR) is a real-time procedure to detect the virus that causes Covid -19 in respiratory specimens. This method involves taking a nasal or throat swab from the suspected patient and extracting the ribonucleic acid (RNA), which is also the genetic material for viruses. If this RNA sample has the same sequence as that of the SARS-COV-2 virus, thx`e result is considered positive.If you have a positive test result, it is very likely that you have COVID-19. The result is negative only if the sample does not contain the virus, or was not administered correctly. Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions. Negative results must be combined with clinical observations, patient history, and epidemiological information which is why RT-PCR is considered the most accurate and effective method of testing for COVID-19.
Benefits of RT-PCR Testing
- Quick and specific: It takes about four hours to six hours to detect the presence of the virus in the batch sample and deliver a reliable result.
- Accuracy: Not only is RT-PCR faster, but it also delivers results that are pretty close to being 100% accurate. The scope for contamination errors is also less likely because the test is carried out in an enclosed tube, inside a specialized, automated machine from beginning till the end.
Limitations of RT-PCR Testing
- Cost: The price of the RT-PCR test is comparatively expensive than other COVID-19 tests. The ICMR had fixed the price of the test kit at ₹4500 up until the end of May, but later on, individual states have been allowed to cap their prices, which almost everywhere in the nation falls between ₹2000 to ₹3000. There is no reimbursement from the government for testing unlike in many developed countries.
- Validity: The validity of the RT-PCR test is over as soon as the test is done, i.e., the validity of the test is only restricted to the day of its testing. Also this cannot test for past infections with SARS-CoV-2. Once a patient has recovered, the test can no longer tell if you had been infected. This leads to uncertainty for people who have self-isolated themselves due to mild and unclear symptoms.
- The need for extensive facilities: The test requires RNA testing machines, trained technicians, and advanced laboratory settings to make it economically viable.
- Limitations of testing locations: Around the country only few centers are approved to do the testing. If a symptomatic patient has arrived at the clinic he is bound to refer the person to a testing site. There is a lack of accountability if the person has actually gone and tested. Also the risk of passing the infection to many more before getting testing and self isolation is a big challenge.
2. Rapid Antibody Tests
Antibody Tests are serological tests that are used to detect the presence of a virus in a body. Here, blood parts samples such as whole blood, serum, or plasma are used to find the antibodies that are produced by the immune system in contact with a virus. The blood is examined for two types of antibodies, Immunoglobulin M (IgM) and Immunoglobulin G (IgG) antibodies. The IgM appears early on in infection, while the IgG antibodies show up later.
Advantages of Antibody Test:
a. Fast Results: These tests give the results in merely 15-20 mins. The Test strip shows colored lines if the test is positive.
b. Low-Priced: The tests are available for rates that fall somewhere between ₹500 to ₹1300 per test.
c. User-friendly: The Antibody kits are small, portable, and can be easily administered on-site.
Efficacy of Antibody Test: The Rapid Test is considered to be an indirect and unreliable method of testing as it cannot find the virus, but can only confirm that the immune system of the body has encountered it. Antibodies develop only 7-10 days after the infection has set in, and by this time, the infected can transmit the disease if not properly isolated. Since this test is nowhere near 100% accuracy, the ICMR has suggested the suspected patients undergo a confirmatory RT-PCR test before treatment, or even after the antibody test is deemed negative.
3. Rapid Antigen Tests
This test aims to detect the presence of the SARS-CoV-2 virus, by seeking out specific proteins that are found only in the virus, i.e., those which the immune system reads as ‘foreign’. This is done by collecting nasal samples with a nasal swab. Usually, most COVID-19 antigen tests target the Spike Glycoprotein that is present on the surface of the coronaviruses.
- The test is conducted in a time span of 20-30 minutes.
- The cost of a Rapid Antigen Test Kit varies all over the nation, fluctuating between ₹450 to ₹750.
A swab sample may have too little antigen to detect the SARS-Cov-2 virus, which may further lead to a false-negative result. Thus, this test should always be followed up by the RT-PCR test, to confirm a true negative for COVID-19.District-Wise-Rapid-antigen-Testing
The ICMR, on the 19th of May, had revised its testing guidelines and allowed the usage of the TrueNAT test for screening and confirmation of the COVID-19 virus.
The TrueNat or the Nucleic Acid Test is a small, portable, chip-based machine that detects the RdRp enzyme found in the SARS-CoV-2 RNA. The viral sample is collected by nose or throat swabs. Due to the automated sample preparation facility, the results of this test are available within half an hour.
TrueNat Test Kits are portable and battery-operated, that allows teams to set-up mobile testing centers in containment zones. They are cheaper than RT-PCR tests and are available between ₹1200 to ₹1300.
Discharge Policy for Home Isolation Patients
The revised Discharge policy of the Govt. of India says that there is no requirement for testing prior to discharge for presymptomatic/very mild/mild COVID-19 cases, after 10 days of onset of symptoms and nil fever for 3 days. This further indicates that no testing is also needed after the home isolation period is over.
Thus, patients with mild cases of COVID-19 are advised to isolate themselves at home & self-monitor their health for seven days. This implies the use of protective gear such as masks, gloves, etc. when moving around the room/house, and monitoring their vital signs regularly with thermometers and oximeters. The use of a COVID Home Care Kit is much recommended for suspected or confirmed mild COVID-19 cases in home isolation.