Interrelationship between CT value of RT-PCR report and COVID-19 infection
Some experts suggest that if the CT value of the COVID -19 RT-PCR report is high, it means that the amount of infection in the infected person is low. In the report, the decrease of CT value is seen to be related to the high incidence of infection. However, according to ICMR the CT value has nothing to do with the severity of the disease.
What is the CT value?
- The CT value is called the ‘cycle threshold’. That is, how many times a cycle is needed to detect the infection in a person.
- If too much cycle was required to detect the virus in a person, it means that there was only a small amount of virus in the person’s body and if the infection was detected in a small number of cycles, then it meant that the person had a high number of virus.
- According to health expert Dr. AmolAnnadate, the CT value does not tell the amount of infection in the person, but it only tells whether the person is infected or not.
Relation of CT value to severity of disease:
- According to many experts, the lower the CT value, the greater the risk of infection on the person and can infect many people. But it has been seen many times that people with low CT value are easily overcome with infection while people with high CT value are severely infected with corona.
- The CT value depends mostly on the immunity of the person. If the CT value is high, you will not be seriously ill, but there is no clear evidence.
Use of different RT-PCR kits in India:
- Different RT-PCR kits are being used in different places in India. Everywhere kit is also different. The CT value of one kit may be different from that on another kit.
- The CT value of the infected person depends on the following:
- How is the sample taken?
- Who has examined him?
- How much sample was taken from the person?
- How many hours was it examined?
- The CT value also depends on the temperature.
- Hence, there is no need to worry too much about the CT value. If the report is positive in RT-PCR test then the person should start its treatment very soon.
Worldwide CT value cut-off between35 to 40:
According to ICMR, the cut-off of CT value is kept between 35 to 40 worldwide. All patients with a CT value of 35 or less will be considered positive while those with a CT value of more than 35 will be negative. Not only this, it is necessary to re-examine patients with a CT value of 35 or less. The CT value cut-off cannot be kept at 24 because in doing so the infection will not be detected in many patients and this will increase the infection.
Source – PIB