New Delhi, Sep 8 (IANS): The Central government on Tuesday said some states were not conducting gold-standard reverse transcription-polymerase chain reaction (RT-PCR) tests on symptomatic people who tested negative for the rapid-antigen test.

Addressing a press conference, Health Ministry Secretary Rajesh Bhushan said,"There are many states where people testing negative for rapid-antigen test are not subjected to RT-PCR. You need to catch that missing person. The people who are not caught are spreading the infection."

"You can chase the virus only if you catch the missing person. This is both Ministry and ICMR guidelines that a person who is symptomatic negative in a rapid-antigen test should be compelled to RT-PCR. If 100 such people are left, they can spread it to a lot of people, and this is worrisome," the Ministry Secretary added.

On August 25, the Health Ministry had claimed that some states were more reliant on moderately-sensitive, cheap and faster antigen tests than the highly sensitive and accurate RT-PCR tests to detect the infection.

The specificity was nearly 100 per cent for both the tests but the sensitivity of rapid-antigen test was of moderate nature and was between 60 tO 85 per cent while that of RT-PCR was from 80 tO 95 per cent, the Health Ministry said.

The clarification came amid speculation that high dependence on antigen tests could lead to under-detection of cases. Several experts have warned that such tests throw up more false negatives.