Srinagar: Kashmir-based doctors on Tuesday said that Covid-19 test results of a person can change within a few hours depending upon the viral load and RT-PCR value.
They said that although human error cannot be ruled out, scientific and clinical evidence confirms that Covid-19 test result shows huge variation in some patients within a short period, depending upon the timing of sample collection, subsequent testing, and status of the virus in the body.
A leading pulmonologist of Kashmir, Dr Parvaiz Koul, told Kashmir Reader that the Covid-19 test result can change from positive to negative within a day or a few hours if the patient’s viral load changes.
The patient can be declared as positive on day one if the samples have a rather low cycle-threshold (CT value), he said.
“And on day two, CT value could just be above the cut-off, though not very significantly different from day one, and it could be correctly reported as negative. So, change in the result is possible scientifically, unless both samples were collected simultaneously and sent to two different labs. In the latter case it can be a clear lab error,” Dr Koul, who also heads the Internal and Pulmonary medicine department at SKIMS, said.
Another doctor, Dr Shahnazwaz B Kaloo, who is working as Consultant for Vascular and Interventional Radiology, said that a positive test means ‘infection’ but a negative test does not always mean ‘no infection’.
“Sampling error is common and it can result in ‘falsely negative’ test. Lastly, if someone tests positive, he shouldn’t repeat it elsewhere. This is a waste of resources,” he wrote on Twitter.
On Monday, controversy emerged over the authenticity of Covid-19 testing in Kashmir after a senior journalist among many who tested positive for Covid-19 at the lab of Chest Diseases Hospital tested negative at other labs, including SKIMS. This discrepancy prompted the Lieutenant Governor of J&K to order a probe into it.
According to Nodal Officer for Covid-19 at Government Medical College (GMC) Srinagar, Dr Saleem Khan, the CD Hospital lab is ICMR approved and comes under Biosafety level 3.
“There is no question that the CD Hospital lab is incorrect in its test reports. The possibility of the results changing is there because in most cases the samples were taken more than 24 hours apart,” he said.
Dr Khan said that the CD lab stands by its reports, and so does GMC Srinagar.
“Some netizens and non-medicos misunderstood the test results,” he said.
Dr Khan said he was happy that the journalist was tested negative of Covid-19. However, he added that CD Hospital microbiologists and GMC Srinagar administration were sure that the journalist was positive earlier as per the lab report.
“We confirmed the samples twice as per the guidelines. He was positive but his viral load might have shown decline when his second sample was taken at SKIMS,” he said.

Manzoor ul-Hassan