I was wondering what could have been the reason for Mandy Zuo to ask the question “Coronavirus: why do ‘recovered’ patients test positive again?”. But one thing is clear. Is the current test for the novel virus accurate and can it be trusted?
Currently, thee commonly used test for covid-19 is the reverse transcriptase-polymerase chain reaction (PCR) test. This is the test that has been used in addition to other epidemiological and clinical details to detain, quarantine and admit patients for management and protection of the populace from danger. With the questions raised in the article, could it be that some people suspected to be infected with covid-19 are being missed and declared negative? Could suspected persons still be a danger to the public because the test might miss detecting their infections?
“Wang Chen, head of the Chinese Academy of Medical Sciences, said last month that only 30 to 50 percent of confirmed cases had a positive result in the PCR tests, and throat swabs had possibly generated many fake negative results.”
The above statement clearly indicates that the test for covid-19 currently in use cannot pick 50 to 70 percent of the suspected people who might have the infection. The danger is huge if these people actually have the infection and may be sent home to continue infecting others.
For most tests, the frequency of repeats on samples increases the sensitivity. The test of sputum for tuberculosis, stool samples for parasites, blood samples for malaria parasite detection are all examples. The same cannot be said about the testing for covid-19 as captured “of the 44 people who met the national criteria for release, 26 tested positive in a third test” … “[But] The rate of a positive result [in a fourth test] for those who have tested negative three times is very low,”.
If about 59% of those declared negative with the test re-tests positive days after, then it is a major cause for worry and a blow to the fight against the new strain of coronavirus in the current outbreak.
The level of trust in the current testing method is low and some do not want to question the quality of the test kit but rather ascribe a proportion of the inefficiency to various factors including improper sample collection, a low dose of the virus, tests done by inexperience personnel, etc.
“Professor Greg Gray from the infectious diseases division at Duke University in the United States and Singapore said that it was unlikely that faulty tests were responsible for the false negatives. “Assuming the laboratories are experienced in running them, I would not expect lab quality to be the problem,” he said.”
“The negative assays might be better explained by a poor quality specimen [not a deep nasopharyngeal swab] or the virus was at a very low count when the swabs were collected.”
Among all these positions, there is evidence that people who were released from the hospital after testing negative can infect others who never had any contact history with infected individuals.
We are all at risk and would add my voice to the search for and development of “new tests that could make the diagnostic process more effective”
Just take the precautionary measure to protect yourself from the person next to you because more than half of the suspected people who may have the infection could test negative by the current test in question.
