E-Paper
Ghaziabad: In 23 days, antigen kits account for half of Covid-19 tests
In just 23 days, more tests have been conducted using the antigen test kits than the reverse transcription-polymerase chain reaction (RT-PCR) tests, considered to
In just 23 days, more tests have been conducted using the antigen test kits than the reverse transcription-polymerase chain reaction (RT-PCR) tests, considered to be the gold standard in testing for the Sars-CoV-2 virus, in Ghaziabad.
According to the official records, the Ghaziabad district till July 18 has performed 64,755 tests, of which 32,325 (49.91%) were under antigen tests, 31,436 under RT-PCR (48.54%) and 994 (1.53%) through TrueNat machines. With total cases at 3,902 in the district, the total positivity rate (TPR, the total number of positives per test expressed as a percentage) was 6.02%. With 848 people testing positive under antigen tests, their share is just over a fifth of all positive cases.
Antigen tests are inherently unreliable with very poor sensitivity, which means its ability to detect true positives is low and could result in many negative tests turning positive under an RT-PCR test. Despite this, its share is high because of two advantages: point of care testing and no need of taking it to a laboratory, and that it gives a result within 30 minutes, as compared to the two days it would take an RT-PCR test.
“It is vital that if a person tests negative under antigen testing, their supplementary test should be conducted through RT-PCR which has higher sensitivity,” said Dr. Lalit Kant, former epidemiology and communicable diseases head at the Indian Council of Medical Research (ICMR). “The antigen tests should be conducted ideally from the fifth to eighth day of a person developing symptoms. Any earlier, then there are chances that test may miss it and the person may spread the infection.”
According to ICMR guidelines, only those who show symptoms after their antigen test need be tested again.
Officially, of the 31,477 people who tested negative under the antigen test, 5086 were re-tested under RT-PCR tests and 405 samples came positive, a TPR of nearly 8%.
Since its first introduction in the district on June 26, a fresh lot of 24,000 antigen kits will now be deployed in different areas, including the containment zones, for speedy tests.
“The antigen kits will now be used widely in containment zones and also in other areas having high risk groups. Its use has lead to speedy results which have helped us in immediate identification, faster referral of patients and even speedier contact tracing of positive cases. We have planned that more focus will be on use of antigen kits and planning to conduct about 3000-3500 tests per day,” said Ajay Shankar Pandey, district magistrate.
In Ghaziabad, July 18 marked 136 days since the positive Covid-19 case was reported.
In March, the case positivity rate stood at 3.36% out of total 149 samples and five positive patients. By April 30, the positivity rate stood at 2.29% with total 2878 samples and 66 positive cases. The rate went up to 3.05% with total 9984 samples and 305 total positive cases on May 31.
By June 30, the total sampling went up to about 20690 with total 1615 cases and positivity rate of about 7.8%. The present positivity rate is about 6.07% with 3902 cases out of total sampling of 64,755 till July 18.
