CT value in RT-PCR tests is used to know if a healthy person is covid-19 positive or negative. If the CT value is more than 24, symptoms start to develop in the body. A healthy person with a CT value less than 35 may be considered as positive while those with a CT value above 35 may be considered as negative, ICMR said. Before declaring someone based on the CT value from the reports it is very much to better understand further completely What is CT value in the Covid-19 RT-PCR test.
A healthy person is considered COVID-19 negative if the CT value is 35 in the RT-PCR test. If a healthy persons’ CT value is below 35 in the RT-PCR test, a patient is a COVID-19 positive.
What Is CT Value?
CT value is the value that emerges in RT-PCR tests, In RT-PCR tests they collect the swab from the person, it is then converted into DNA, which is then amplified. Amplification takes different series of cycles, one copy of DNA becomes two, two becomes four, and so on. These multiple series of cycles indicate viruses in the body. This test helps to detect the presence of viruses in the body.
According to ICMR, CT value in RT-PCR indicates whether coronavirus is present in the body or not. CT value depends on the number of series of cycles after the virus is detected. If the number of cycles is more, the CT value is more; the virus is not present in the body, if the number of cycles is less, the CT value is less than the virus is present in the body.
Why Is CT Value Important?
CT value is important to check whether the COVID-19 virus is present in a healthy person or not. CT value indicates whether the virus is present or not. A lower CT value indicates a higher severity of the virus, higher CT value indicates lower severity of the virus. If the CT value is 35 in the RT-PCR test it indicates covid-19 negative. If the CT value is below 35 in the RT-PCR test it indicates covid-19 positive.
According to American Association for clinical chemistry, CT refers to the number of cycles to amplify RNA to reach a detectable level. Specimens with lower CT values will have higher RNA whereas specimens with higher CT values will have less RNA. A better understanding of what is CT value in the Covid-19 RT-PCR test will help in determining a COVID patient irrespective of whether they are asymptomatic or Symptomatic.
How To Determine CT Value?
CT value depends on the number of cycles after the virus is detected. CT value and virus is inversely correlated. A patient with a low CT value indicates the virus is high in the body. If the CT value is low it indicates the virus is low in the body. CT value is determined by collecting swabs from the person, it is then converted to DNA, which is then amplified.
How To Calculate CT Values?
When a swab is collected from the person, it is then converted into DNA, which is amplified. Amplifications take different series of cycles. If the number of cycles is more CT value is more, the virus is not present in the body. If the number of cycles is less CT value is less then the virus is present in the body.
Normal CT Levels
Normal CT levels indicate that virus is present in the body. Worldwide acceptance that CT value is above 35 to 40 indicates the covid-19 virus is present in the body.
Low CT Levels
Lower CT values indicate that there is no virus in the body. A high CT value indicates there is a virus in the body. A poorly collected virus does not give exact results in RT-PCR.
A small study in the Indian journal Medical Microbiology found that there is no relation between CT values and the severity of the disease. Symptoms have a stronger relationship with CT values than the severity of the disease. CT value indicates a virus present in the throat, not in the lungs. CT value does not correlate with the severity but it correlates with infectivity. Firstly, we should consider infectivity present in the body, next consider CT value and decide whether the patient is covid-19 or not. RT-PCR test results depend on the exact method of specimen collected for analyzing the virus present in the body.
Tips To Take Care While Confirming The Results
- Be sure not to decide just with the CT value.
- Look for other factors too like when was the sample collected, what reagents were used, etc.
- Store the sample appropriately.
- Be understood that CT value has no correlation with the severity and it relates only to the infectivity.
Hence with all the understanding gained about what is CT value in the Covid-19 RT-PCR test, also considering the other factors a person is declared COVID positive or negative by your medical practitioner.
Sudheendra is a passionate blogger for 8 years and holds a Degree in Journalism & Mass Communications. His writings particularly focus on health, medicine, diet & lifestyle. For him, everything that interlinks and relates to health & medical world entices him. His write-ups aim at educating people not by just giving facts but by infusing human touch.