Safe Blood – A basic right of all human beings
Dr. K. Narayanan Kutty, Secretary, IMA Blood Bank
IMA Voluntary donor blood bank believes that safest blood is the birthright of all human beings and to achieve that goal it is launching for the first time in Kerala Nucleic acid amplification testing whereby the window period of infections can be closed. We will also take samples from hospitals and other institutions for nucleic acid amplification testing and hence this facility of the blood bank will be beneficial to all hospitals in and around Ernakulum. We seek cooperation of all IMA members and hospitals by requesting NAT blood and also sending samples for NAT. Transmission of infective diseases to transfusion recipients has been drastically reduced due to effective screening of donor blood using serological markers. However, transmission of infectious agents via blood transfusion still occurs and despite antibody-based blood-donor screening, a residual risk of transfusion-transmitted viral infections exists. This is because it is not possible to detect infectious agents during the pre-sero-conversion (“window”) period. Recent advances in technology have now provided for even more sensitive and advanced methods to screen for infections in donated blood in addition to the compulsory basic screening tests.
What are these infectious agents?
Hepatitis B (HBV), Hepatitis C (HCV), and Human Immunodeficiency Virus (HIV) are infectious agents which are blood-borne pathogens. All three infections are
caused by viruses that are transmitted through exchange of body fluids (blood, semen, and vaginal secretions). AIDS, caused by the HIV, remains the most feared,
although HBV is more easily transmitted.
What is window period?
The window period is the time between the point when the blood donor contacts the infectious disease and the time it takes to detect the infection in the blood by
standard serologic techniques. The greatest threat is donation by Sero-negative donors during window period between initial infection and detectable antigen or
sero-conversion. This blood will test negative by standard serology methods and can be transfused to a recipient or more, leading to a transfusion transmitted infection.
What is NAT?
Nucleic Acid (RNA / DNA) Amplification Testing (NAT) employs a testing technology that directly detects the genetic materials of viruses like HCV and HIV. This technology detects very low levels of viral RNA or DNA that may be present in donor blood. It assists in diagnosing infections at an earlier stage and can therefore prevent transfusion transmitted infections such as the feared HBV, HCV as well as the deadly HIV. These infectious agents are caused by viruses that are transmitted through exchange of body fluids. Although AIDS, caused by HIV remains the most feared, hepatitis B is more easily transmitted and particularly seen more frequently in South East Asia.
What is the technology?The unique system has been extensively validated and widely implemented for blood bank tests to enhance blood safety. NAT technology has been preferentially
implemented in the US, Europe, Middle East, Africa and the Asia Pacific region. Individual Donor NAT (ID NAT) test is performed for each and every donor samples to reduce or practically eliminate the ‘window period’.
NAT assists in detecting infections at an earlier stage and reduces risk of transfusion transmitted infections.
Improves public confidence in the safety of the blood supply and is a step closer to providing “zero risk” blood.
Eliminates healthcare costs for diagnosing and treating infections (HCV, HBV, HIV) when these infections occur due to infected-transfusions.
Potentially decreases litigation and negative publicity arising in the case of transfusion of infected blood.
Allows for compliance with International standards in blood safety. In addition to blood safety, NAT testing potentially decreases litigation and negative publicity arising in the case of infected blood transfusion. Most importantly, implementation of NAT also allows for compliance with International standards in blood safety. The blood manufacturing community has approved and begun gradual implementation of Nucleic Acid Amplification Testing (NAT) globally under the FDA’s Investigational New Drug (IND) application process since 1999.
Are you aware of the potential impact of a single infected unit of blood collected from an infected donor?
A single unit of whole blood collected from an infected donor in the window period of infection may potentially be transfused into up to four recipients or may be
added to pools of more than 1,000 units to manufacture blood-derived products. So it is high time to declare that safe blood is the basic right of all citizens. Together we can work for it.
FREQUENTLY ASKED QUESTIONS & ANSWERS
What is NAT?NAT is Nucleic Acid Testing and is a molecular method for detecting the presence of genetic material (RNA/DNA) in the sample. It is more specific and sensitive as it detects very low amount of genetic material which cannot be identified by other methods.
What parameters will be tested?NAT can screen for three viruses – HIV-1, HBV and HCV in donor blood samples.
How is it different from Elisa?Elisa is a serological method detecting the presence of antigen / antibody in the blood sample. These take some time to
appear after infection and this time gap is known as “window period”. But the viral genetic material (RNA/DNA) can be found very soon after infection. NAT
identifies these genetic material thereby reducing this window period.
How does it make blood unit safer?NAT provides an additional layer of blood safety by able to detect very low amount of genetic material in the blood which
are prone to be missed by other methods. This is very crucial in occult and window period transfusions.
Should both EIisa and NAT be done?Currently, Elisa is approved by FDA and NACO and is mandatory for blood banks to test blood before issue. NAT is also
being considered to be made mandatory. Many other countries like USA, France, Germany, Australia, Thailand, Malaysia etc. have implemented NAT.