Diagnostics

Indraprastha Apollo brings NAT to India

NAT is more sensitive than conventional blood tests that require the presence of antibodies to trigger a positive test result

Nucleic Acid Testing (NAT) is a method of testing blood that is more sensitive than conventional tests which require the presence of antibodies to trigger a positive test result. In India, Indraprastha Apollo Hospitals, New Delhi has taken the initiative for NAT implementation for the first time in the country.

NAT uses procleix ultrio assay for the screening of Human Immunodeficiency Virus-1 (HIV-1), Hepatitis B (HBV) and Hepatitis C (HCV) virus in donated blood. This test is the first simultaneous, single tube NAT solution for HIV-1, HCV and HBV. It is a direct test which actually detects the viral nucleic acid (RNA/DNA) "Being a direct test, it reduces the window of detection for all these three viruses from the current available serological (ELISA) tests," informs Dr RN Makroo, Director, Blood Transfusion Medicine, Indraprastha Apollo Hospital, New Delhi. NAT combines the advantages of direct detection of the organism with sensitivity several orders of magnitude higher than that of traditional methods. The benefits of NAT are that it works by detecting the low levels of viral genetic material present when an infection occurs but before the body begins producing antibodies in response to a virus. In addition, NAT significantly reduces the 'window period' or the time between donor exposure to the virus and the appearance of detectable amount of antibodies. "By decreasing the window period, it allows for earlier detection of the infection and thus further decreases the possibility of transmission via transfusion," avers Dr Makroo.

India has more than 2,000 blood banks. Despite the current practice of blood screening with Government approved kits, chiefly employing enzyme immunoassay technologies, a recent survey of blood transfusion practices noted that testing for potential transfusion-transmitted infections is unsatisfactory and poorly regulated in most blood banks, regardless of their type and location. It is imperative that patients receiving blood during transfusion be provided with infection free blood. "Thus, to increase the chances of detecting HIV, HCV and HBV in the blood, NAT has now been introduced in India," says Dr Makroo.

However, the efficacy of NAT can be extremely variable between areas with different prevalence of HIV, HBV and HCV and within the same geographical area, between donors of different social and geographical origin.

Some of the foreign countries already utilising the benefits of NAT are Australia, New Zealand, Belgium, France, South Africa, Egypt, the UK, the US, Canada and many more.

EH News Bureau