Advanced blood screening nullifies infection in recipients
Blood donors may not be aware they are carriers of infections such as HIV, Hepatitis B virus (HBV) or Hepatitis C virus (HCV). When their blood is not tested thoroughly, the possibility of infecting recipients is high.
A 26-year-old woman in Hubli was given O +ve blood during the delivery of her second baby. She tested positive for HIV when she returned to the hospital for a family planning operation nine months later. Her brother, K Prakash, told The Hindu that doctors had found that she contracted the infection through blood transfusion. “My sister’s life has been ruined. How do we know that the blood that we receive from blood banks is safe? Aren’t the blood banks supposed to ensure that cent per cent safe blood is supplied to patients?” he asked.
The infection could have been avoided if blood donated to her had been tested using the Individual Donor-Nucleic Acid Testing (ID-NAT) method, which is an advanced screening technology, said H.N. Ravindra, Deputy Director of Karnataka State AIDS Prevention Society (KSAPS).
All the 178 blood banks in Karnataka, except the one at Bowring and Lady Curzon Hospital, use the conventional serology testing method to detect virus in blood samples.
The blood bank at Bowring Hospital, run by the government in coordination with a private partner, has adopted the individual donor-nucleic acid testing (ID-NAT) method. The ID-NAT method looks for the genetic material of the disease-causing organisms and can detect infections in donated blood quicker than the conventional serology tests.
Explaining the effectiveness of ID-NAT, Zaheer Ahmed, Bowring Hospital blood bank officer said: “ID-NAT assays can detect HIV-1 within 4.7 days after infection as against 15 days taken through ELISA (serology). This reduces the risk of infection by 90 per cent,” he said.
“While it takes 58.3 days and 38.3 days to detect HCV and HBV respectively through ELISA (serology), it can be detected within 2.2 days and 14.9 days post-infection using NAT,” he said.
The ID-NAT bank tests an average of 300 samples every day. A total of 1.3 lakh blood samples of donors sent from 30 government blood banks across the State have been tested since June 2011 when it started functioning.
Elaborating on the efficacy of the ID-NAT method, S. Manjunath, technical director of the laboratory, said serology tests do not determine the infection in its ‘window period’ (the time taken by the virus to get into the body and become reactive). “As a result of this, we can reject the blood much earlier,” he said.
Apart from the All India Institute of Medical Sciences in Delhi, Karnataka is the first to have taken the initiative to test blood samples collected in Government banks using ID-NAT.
Calling upon people to ask for ID-NAT blood when they get blood for transfusion, Mr. Manjunath said: “The cost difference between the ID-NAT-tested and ELISA-tested blood units is around Rs. 300 because of the expensive reagents used for testing. But when it comes to safety, spending Rs. 300 extra is worth it,” he said adding that all blood banks should use this advanced method.