Medical Journal of Dr. D.Y. Patil Vidyapeeth

: 2022  |  Volume : 15  |  Issue : 1  |  Page : 49--53

Experience of individual donor nucleic acid testing on screening of blood donors for human immunodeficiency virus, hepatitis c virus, and hepatitis b virus at an Apex blood bank of Northern India

Rajat Jagani1, Ujjwal Dimri1, Satish Kumar2, Amit Pawar1,  
1 Armed Forces Transfusion Centre, Delhi, India
2 Department of Transfusion Medicine, Madhukar Rainbow Children Hospital, Delhi, India

Correspondence Address:
Amit Pawar
Armed Forces Transfusion Center, Delhi Cantt, Delhi - 110 010


Context: There is an ever-growing concern for the safety of blood transfusion with regard to the transmission of human immunodeficiency virus (HIV), hepatitis C (HCV) virus, and hepatitis B virus (HBV). About 11 million blood units are being collected in India every year. Instances of viral transmission through transfusion still occur as a result of donations that take place while a donor is in the pre-seroconversion window phase. Aim: The aim of the study is to analyze 4 years data of nucleic acid testing (NAT) for our blood donor population and validate the benefits of implementing individual donor NAT (ID-NAT). Subjects and Methods: A total of 54,895 blood donor samples were tested by ID-NAT method between January 2016 and December 2019. ID-NAT results and corresponding serological test results were collected and correlated for the identification of ID-NAT yield cases (seronegative/NAT positive) to identify the potential infected samples which may not be detected by the serological testing. Results: Of the 54,895 samples tested, there were total 71 samples which were serologically negative but detected by ID-NAT (ID-NAT yield). Among these 71 ID-NAT Yields, 3 were HIV, 12 were HCV, 46 were HBV, and 10 cases were reactive for HBV-HCV co-infections. Our combined ID-NAT yield rate was estimated to be 1 in 773 donations tested. Conclusion: Higher incidence of NAT only reactive donors poses a risk of transfusion transmissible infections in blood centers not adopting NAT. HBV NAT displays the highest yield, thereby recommending the universal adoption of NAT for all three viral markers, namely HIV, HBV, and HCV in our country.

How to cite this article:
Jagani R, Dimri U, Kumar S, Pawar A. Experience of individual donor nucleic acid testing on screening of blood donors for human immunodeficiency virus, hepatitis c virus, and hepatitis b virus at an Apex blood bank of Northern India.Med J DY Patil Vidyapeeth 2022;15:49-53

How to cite this URL:
Jagani R, Dimri U, Kumar S, Pawar A. Experience of individual donor nucleic acid testing on screening of blood donors for human immunodeficiency virus, hepatitis c virus, and hepatitis b virus at an Apex blood bank of Northern India. Med J DY Patil Vidyapeeth [serial online] 2022 [cited 2022 Sep 29 ];15:49-53
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Safety of blood products is one of the key issues in transfusion medicine. Screening of blood donors for transmissible infectious agents plays a major role in decreasing the risk of transfusion of infected blood units. Currently, blood banks in India are mandated to follow immunoassay-based blood screening assays. However, the risk of transfusion transmissible infection (TTI) from screening of donated blood by serology-based assays has been established owing to the long window period.[1] Window period of an assay is described as the time required by an assay to detect the infection, postinfection, and prior to seroconversion. Limitations of mandatory serological screening techniques include window period between infection and detection, occult infections, and presence of mutated or variants of known pathogens. Nucleic acid testing (NAT) provides an additional layer of safety for blood and blood products. It is a molecular amplification test, which directly targets, amplifies, and detects viral genetic materials (RNA/DNA) in blood donor samples. NAT is a highly sensitive and specific method for the detection of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). Unlike antibody testing, this technique directly tests for the presence or lack of the viral RNA or DNA by the amplification of specific nucleic acid sequences.

The technological advancement of individual donor-NAT (ID-NAT) in blood screening prevents transmissible viral infection primarily by substantial reduction in the window period as compared to routine serological tests such as enzyme-linked immunosorbent assay (ELISA) and chemiluminescence immune assays. In addition, NAT is also beneficial in detecting occult hepatitis cases, mutants, and variants which may escape the detection by serological tests.[2] It is estimated that ID-NAT reduces window period for HIV to 2.9 days, HCV to 1.3 days, and HBV to 14.1 days.[3]

NAT testing has not only increased blood safety, but has also provided insights into the epidemiology, natural history, and pathogenesis of viral infection.[4] As per the International Society of Blood Transfusion, working party on transfusion-transmitted infectious diseases, 10 years data from 33 countries covering 300 million donations show a total of 2808 virus-contaminated donations.[5] These donor blood units would have been transfused, if NAT had not been used for TTI screening.

Our blood center implemented ID-NAT since January 2011 as a routine blood screening assay for HIV, HCV, and HBV for blood donors. The study presents 4 years ID-NAT screening test data from January 2016 till December 2019 with an objective to estimate the NAT yield for all blood donor samples tested for HIV, HBV, and HCV over a 4-year period.

 Subjects and Methods

This study is a retrospective, observational study carried out on all the blood donor samples collected between January 1, 2016 and December 31, 2019 and had the approval of the Institutional Ethical Committee of the center (Ref: IECHS/AFTC/BTD/11 dated February 20, 2020).

ID-NAT was implemented at our center in January 2011, using Procleix Ultrio Assay (Grifols, CA, USA) on Procleix eSAS System. Subsequently, the second-generation Procleix Ultrio Plus ID-NAT Assay (Grifols, CA, USA) was introduced using the same eSAS platform in January 2014. Recently, in March 2019, our ID-NAT system was upgraded to a fully automated Procleix Panther System using Procleix Ultrio Elite Assay (Grifols, CA, USA). Procleix family assays are based on Transcription Mediated Amplification technology for the screening of HIV RNA, HCV RNA, and HBV DNA in the donor plasma.

All prospective blood donors reporting to the blood donation center were administered a Donor Health Questionnaire based on the available guidelines as promulgated time to time by the Directorate General Health Services, Ministry of Health and Family Welfare, Government of India and National AIDS Control Organization, Ministry of Health and Family Welfare, Government of India.

At our blood center, the donated blood is serologically screened for HIV, HBV, and HCV using 4th-generation HIV ELISA, 3rd-generation HCV ELISA, and 3rd-generation HBV ELISA. The HIV fourth-generation ELISA is used for the qualitative detection of p24 antigen and antibodies against HIV 1 + 2 in human serum/plasma. The third-generation HBV ELISA method is a sandwich type ELISA which qualitatively detects the HBsAg in human serum/plasma. The third-generation HCV ELISA technique qualitatively detects the antibodies against HCV. The details of kits used in this study are as given in [Table 1]. The ELISA was run strictly as per the manufacturer's instructions with the positive and negative controls as provided by the manufacturer along with known positive controls for HIV, HBV, and HCV prepared in the laboratory and plotting of Levy-Jennings charts. Westgard Rules were used to analyze every ELISA run.{Table 1}

Both ELISA and ID-NAT were performed in parallel. Blood units initially reactive for either ELISA or by ID-NAT were discarded and not used for transfusion.


A total of 54,895 donors were screened during January 2016 and December 2019. Out of 54,895 donors, 51,020 donors were tested using Procleix Ultrio Plus Assay using Procleix eSAS System and 3875 donors were screened using Procleix Ultrio Elite assay on Fully automated Procleix Panther System. All the donations were tested using individual donor test method, where in each donor sample was tested individually.

Among 54,895 blood donations, 43,888 (79.95%) were voluntary, whereas 11007 (20.05%) were replacement donations. Of these, 71 (0.13%) donor samples were found to be reactive by ID-NAT but nonreactive by routine serological testing. These donations were termed as ID-NAT Yields and are largely due to serological window period and occult hepatitis B cases. Among the 71 ID-NAT yield cases, 3 were HIV, 12 were HCV, 46 were HBV, and 10 cases were HBV-HCV co-infections. The year wise distribution of NAT yield is shown in [Table 2].{Table 2}

ID-NAT yield cases detected by Procleix Ultrio Plus and by Procleix Ultrio Elite assays are 65 (0.13%) and 6 (0.15%), respectively. Overall ID-NAT yield rate was found to be 1 in 773 donations tested. The ID-NAT yield rate for Procleix Ultrio Plus Assay was 1 in 789 donations and for Procleix Ultrio Elite was 1 in 646 donations tested. The distribution of ID-NAT yields is shown in [Table 3].{Table 3}


Data with respect to serology-based assays for blood screening have lowered the TTI risk by a great margin. However, serology-based assays have a long window period, also known as diagnostic window period, during which the virus can escape detection. With the reports of TTIs evading serology based screening and increased knowledge about different viral markers, NAT emerged as a tool to shorten the diagnostic window period. During 1990s, many developed countries started experimenting with NAT and adopted it as a mandatory screening tool along with serology.[5] By the mid of 2015, a total of 31 countries had implemented NAT as a routine screening.[6] In India, the first NAT for blood screening was evaluated in 2004 at Indraprastha Apollo Hospitals, New Delhi.[7] Published NAT yield data from different Indian blood banks report varying NAT yields. All India Institute of Medical Sciences, New Delhi, has reported a NAT yield of 1 in 847[8] and from the same region, Sir Gangaram Hospital reported a NAT yield of 1 in 2028.[9] From the state of Karnataka, TTK Rotary Bank reported 1 in 5000 NAT yield.[10] In our experience, calculated NAT yield of 1 in 773 is higher compared to most of the other blood bank's NAT yield rates in India. A review article by Kanjaksha Ghosh and Kanchan Mishra published in the Indian Journal of Pathology and Microbiology in September 2017 reviews the NAT yield published in various studies carried out all across India from 2008 to 2016.[11] The NAT yield at these centers varies from 1 in 476 (AIIMS, New Delhi) to 1 in 17,753 (Manipal Hospital Blood Bank). The estimated NAT yield in this study of 1 in 773 is on the higher side but comparable with the NAT yield obtained at DMC, Ludhiana, Punjab (1 in 767) and Apollo Hospital, New Delhi (1 in 686).

Considering 100% component separation done at our center, transmission of more than 100 infections was interdicted by NAT testing from different infected blood components. The prevalence and incidence rate of viral diseases, in donor as well as general population, is variable all over the country. A variance in the NAT yield data from different published data can be explained based on these above factors. Other than that, different NAT assays of varying sensitivities in-use and different algorithms followed also impact NAT yields. In addition, the sensitivity of the serology-based assay can also impact NAT-yield. It is no surprise that our NAT yield of 1 in 773 is higher than that from US (1 in 2 million for HIV, HCV),[12] Germany (1 in 431,843),[13] and Japan (1 in 48,262).[14] Developed countries with 100% repeat voluntary blood donors, more sensitive serological kits and use of additional serological markers such as antiHBc and antiHBs, etc., are expected to have far lower NAT yield than India.

The choice of ID-NAT over Minipool NAT (MP-NAT) was important to us. There are multiple publications and reports from various countries about higher sensitivity of NAT when performed in Individual Donor format.[15],[16],[17] ID-NAT also has lower window period and higher detectability compared to Minipool Testing.[3],[18] Reports of missed cases by MP-NAT[19] and resultant TTIs[20],[21] were a relevant factor in choosing ID-NAT for our center. Choice of ID-NAT or MP-NAT should be based on the regional requirement rather than following blood safety guidelines of first world countries where the blood safety standards, donor prevalence rates differ significantly compared to our region.

Our experience with ID-NAT at our center depicts a high yield for HIV, HCV, and HBV. Higher incidence of ID-NAT only reactive donors poses a risk of TTI in other blood centers not adopting NAT. HBV NAT displays the highest yield, recommending the universal adoption of ID-NAT for all three markers in our country.


Higher incidence of NAT only reactive donors poses a risk of TTIs in blood centers not adopting NAT. HBV NAT displays the highest yield, recommending the universal adoption of NAT for all three viral markers, namely HIV, HBV, and HCV in our country.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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