Neha Sharma, 31, mother of two children aged 4 and 6 months first had a fever, mild cough and a terrible body ache. Days after, she lost her sense of smell. But her COVID-19 test came negative. It was followed by a 17-day long isolation away from her young children. "I took a retest and tested negative again. I was asked to do some blood test, and everything came out fine. I consulted multiple doctors and all of them confirmed I had COVID-19 symptoms. But the tests said otherwise," Sharma told BOOM.
Sharma is not alone. Arun Krishnan, 49, who runs his own HR analytics firm, tested negative the first time, while his wife and daughter tested positive. After 3 days of experiencing body ache and fever, he retested again and was found COVID positive. Once he tested positive, the doctor then advised home isolation and a few other tests. Krishnan shared, "At one point my oxygen saturation dropped to 93%, so the doctor asked me to get admitted to a hospital. Luckily, I found a bed. At the hospital, they just monitored me and gave me intravenous medication. Two days later, I was discharged." The 49-year-old says he has fully recovered now.
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What is a false negative?
Diagnostic tests for COVID-19 include (both the slower, more common, and considered as the golden standard for testing) called the RT-PCR – and (the more rapid vial protein test), called a Rapid Antigen Test (RAT). While the RAT test typically serves to confirm a past infection who have since then recovered from COVID-19, rather than detect an active infection, the RT-PCR is to confirm the presence of the virus in the body. If you test negative through either, chances are high that you could still be COVID positive. Experts have expressed concern over an increase in false negatives. A false negative is when the virus does not show up in the tests even though the person has contracted the infection. It is not only worrying for the patient but he/she can also turn into a silent carrier of the virus, without accurate results. Furthermore, if the mild symptoms are not treated in time, there are chances of them mounting into severe symptoms, thus hampering the patient's overall health condition.
Why a negative test does not rule out COVID-19?
Last year, one study by Johns Hopkins Medicine, found out that RT PCR-based tests may miss more than 1 in 5 COVID-19 cases. The primary reason for the false-negative tests among COVID-19 patients can be attributed to errors by lab technicians who may be having a sharply increased workload in the second wave. Alternatively, some test kits may be missing emerging mutant strains. More and more experts agree that how the test specimens are collected and processed may have a lot to do with false negatives. For instance, the technique through which the swab is taken matters. "You have to take a deep swab, right through your down through your nose, right into the back of your throat. While taking the swab, if the back of your throat hurts, that is when you know, you have taken a proper swab," clarifies, Dr. Behram Pardiwala, Internal Medicine, Wockhardt Hospitals Mumbai Central.
What should you do, if you experience Covid-19 symptoms, despite testing negative?
Dr. Sameer Sahu, Director, Pulmonology & Critical Care, AMRI hospital, Bhubaneswar, and a Patron at SeekMed, explains, "No clinical diagnostic tests are 100% accurate. From what we have seen so far, for rapid antigen tests, 50 % of cases are negative. For the gold standard test- RT PCR, the positivity rate is 70%. This simply means if 100 people have COVID, 30 people will be negative. But the most important point to note is to look out for the common symptoms associated with COVID. In an epidemic surge, like what we are seeing right now, entire families are getting infected. Even the slightest of fever should be considered as a symptom. So, if a patient develops a symptom like fever, they must observe strict self-isolation at home for 10 days."
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Health Minister Dr Harsh Varshan tweeted out revised guidelines for people under home quarantine, reaffirming majority of COVID patients don't require hospitalization and can recover at home maintaining utmost precaution.
Patients with mild symptoms do not need CT Scan: If symptoms persist and are suggestive of Covid, then a person should wait for at least 2-3 days, before doing a CT scan, Dr. Sahu adds. "If the CT scan is done very early, before pneumonia, cough, or other respiratory symptoms develop, one might miss the diagnosis. But once the symptoms have developed and then a patient does the CT scan, then it would show up and the chance of a missed diagnosis would be very low."
Our social behaviour is critical in breaking the chain. Dr. Sahu insists staying home and keeping calm is very critical. "Use masks and avoid rushing outside for multiple tests. If one person gets infected in the house, then we are seeing the whole family get infected. COVID appropriate measures inside and outside home is the only way out."
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Is plasma donation possible in such a case?
The plasma therapy aims at using antibodies from the blood of a recovered COVID-19 patient to treat those critically infected by the virus. It has been claimed that the plasma contains that antibodies that can help a patient fight the pathogen and recover from the disease.
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A 2016 study by scientists from the National Institute of Italy calls this a passive immunization methodology. Passive immunization is an artificially acquired immunity used by collecting antibodies from the serum of other animals and are inserted into the bodies of the infected. However, multiple studies have indicated that convalescent plasma offers no tangible benefits to COVID-19 patients. A recent study conducted on five critically ill COVID-19 patients suggested that there is potential for plasma therapy to be considered as a treatment but there will have to be many clinical trials.
So can a person who has tested negative donate plasma? Dr. Pardiwala, says, "It's a question of when you give the patient plasma. If you give the patient plasma, real early in the disease process, before it takes turn for the worse, then it does seem to work. For the donor, it depends on the antibody titer and quality. After 2-3 months, if your antibody titer is high enough, you can donate plasma." Dr. Priyanka Nadkarni, a physician practicing in Mumbai who BOOM spoke to said, "if a person has tested negative all throughout, as per ICMR guidelines, that person can't donate plasma."
The author is a freelance writer and a fellow at @SRFmentalhealth.