Govt should conduct antibody tests along with PCR for Covid-19: scientists

Medical scientists suggested government incorporate antibody tests along with PCR tests for Covid-19 to ensure large-scale screening which is deemed crucial to check transmission of the virus.

The government until now has approved only PCR tests, but the scales at which tests are being conducted -- around 8,000 to 10,000 a day -- is very limited compared to the required number of tests for a population of nearly 17 crore.

Scientists say both PCR and antibody tests have some limitations, but now is the time when use of both types of kits can complement each other. The recommendations came during a virtual scientific seminar organised by Gonoshasthaya Kendra today.

"We don't know the actual number of people affected by Covid-19 because the rate of testing is very low here. We cannot devise an effective strategy based on this rate of tests," said Prof Muzaherul Haque, former advisor to the World Health Organization.

The accuracy level of PCR tests depends on the efficiency of swab collection from throat and nose. Its false positive or false negative can be between 30 and 40 percent, Prof Muzaherul said.

"Our health system has a huge management problem. Are we prepared if 12 crore people of the country are infected and five percent of them are to go through hospital treatment?" he questioned.

The suggestions come at a time when 386 people have died of coronavirus and the number of infections recorded until today is 26,738. A team of Gonoshasthaya Kendra led by Dr Bijon Kumar Sil, developed Rapid Dot Blot kit that can test both antibody in blood and antigen in saliva.

Gonoshasthaya Kendra applied for registration of the kit in mid-March, but is yet to get approval for mass production. The kit is now going through performance trial at the Bangabandhu Sheikh Mujib Medical University (BSMMU).

At the seminar, Dr Bijon said no single test should be considered as the gold standard and authorities should go for both antibody and antigen tests.  

"The new coronavirus can last in saliva longer than in droplets from sneeze. If saliva is left on the soil, it dries up and then the virus can mix into the air," he said.  

Dr AK Azad Chowdhury, a noted biochemist and former vice chancellor of Dhaka University, said if anybody tests negative in antibody tests, then a PCR test can be conducted on him/her for a comprehensive result.

Antibody and antigen tests may not be 100 percent accurate, but large-scale and quick tests are possible through this, he said.

Prof Kamrul Hasan Khan, former vice chancellor of BSMMU, congratulated Dr Bijon Kumar Sil for development of Rapid Dot Blot, and added that that there was nothing to make controversy out of it.