False positive viral marker results in blood donors and their unintended consequences

Detection of hepatitis B virus surface antigen, IgM and IgG antibodies to hepatitis B virus core antigen in the clinical classification and epidemiological surveillance of HBV infection

Hepatitis B virus surface antigen (HBsAg), IgM and IgG antibodies to hepatitis B virus core antigen (anti-HBcIgM and anti-HBcIgG) comprise serological markers of hepatitis B virus (HBV) infection of great importance in the epidemiological surveillance of hepatitis B, since they have been routinely considered for classifying the acute and chronic clinical forms of HBV infection. This classification is established according to the expression and dynamics of these markers in the infected person's bloodstream, which serves as the basis for the differential diagnosis between the two clinical entities. However, in certain circumstances, both acute and chronic infection, the detection of these markers may not occur in the bloodstream, favoring the occurrence of atypical serological profiles of infection, and compromising the correct infection clinical classification. In addition, the complex and varied nature of hepatitis B serological profiles may compromise the health professional's ability to analyze the case and, thus, correctly classify the infection's clinical form. Since the expression of these markers in the bloodstream occurs dynamically, with consequent changes in the patient's serological profile as he progresses towards recovery or chronicity, the diagnosis of acute or chronic infection may also be compromised, if it is established based on the collection of a single sample and without knowing the patient's clinical history and their epidemiological antecedents. This manuscript addresses the sensitivity and specificity of HBsAg, anti-HBcIgM, and anti-HBcIgG serological markers detection in the clinical classification of HBV infection and in the epidemiological surveillance of hepatitis B. This review is covering the clinical and epidemiological interpretations of the markers in and of themselves, not in reference to any specific assays.

Safety of Hepatitis B Virus Screening in Blood Donors from the Hospital Foundation of Hematology and Hemotherapy of the State of Amazonas (HEMOAM) in the Brazilian Amazon

BACKGROUND

Hepatitis B is an infectious disease of worldwide importance and of great interest to transfusion medicine. The Amazon region has areas of high endemicity, outlining a worrying scenario for transfusion and epidemiological safety.

OBJECTIVE

To analyze the profiles of serological and molecular markers for HBV of blood donors from HEMOAM.

METHODS

Blood donors with different patterns of reactivity in serological and molecular screening for HBV were tested for viral load by the qPCR method at the reference center for liver diseases in the state of Amazonas.

RESULTS

A total of 230,591 donors were tested, with 3104 (1.34%) found reactive for HBV and 2790 (89.9%) found reactive for isolated anti-HBc. Viral load was not detected in 100% of donors reactive only to HBsAg, while 100% of donors with positive anti-HBc and positive HBsAg or HBV NAT demonstrated a detectable viral load. We also detected one case of occult hepatitis B (0.03%) only with reactive HBV NAT and five donors (0.2%) with positive anti-HBc and HBV NAT.

CONCLUSIONS

With this result, the great importance of the anti-HBc test for the unsuitability of blood donors was verified, as well as the fundamental introduction of the HBV NAT test in screening for hepatitis B in Brazilian blood banks, as this was the only way to detect the viral infection burden in asymptomatic donors who previously would not be treated, which contributed to the maintenance of the endemicity of hepatitis B in the Brazilian Amazon.

Notification and follow-up of blood donors reactive for transfusion-transmitted infections: A narrative review of the literature from India

BACKGROUND AND OBJECTIVES

Notifying blood donors of their reactive status for transfusion-transmitted infections (TTIs) plays a vital role in enabling early diagnosis and management while also preventing these donors from making future donation and transmission of the infectious agent. Given the limited data on donor notification processes in India, a narrative review was conducted to assess the existing notification process and identify areas requiring enhancement.

MATERIALS AND METHODS

We conducted literature searches using PubMed, Google Scholar and Scopus, employing various keywords. The review included data on the year of the study, study design, donor numbers, TTI screening methods, sero-reactive donor confirmation, notification frequency and methods, donor responses, post-test counselling and risk factor assessment.

RESULTS

Out of the 29 identified articles, 16 studies were included in the analysis. Repeat testing for initially reactive results was conducted in nine studies for 24.3% reactive donors. Phone calls were the primary notification method in most studies (8; 50%), with letters sent in cases of no response. Only 12 studies provided data on notified donors, revealing a notification rate of 71.2%. Of all initially reactive donors, 33.3% sought post-test counselling. Data from six studies indicated that 74.3% of responsive donors had identifiable TTI risk factors.

CONCLUSION

Our review revealed significant variability in the notification processes across different studies. To enhance the management of TTI-reactive donor notifications and responses, we recommend the establishment of universal protocols encompassing pre-donation counselling, repeat/confirmatory testing, notification methods and comprehensive follow-up and treatment.

Establishing a screening strategy for non-discriminatory reactive blood donors by constructing a predictive model of hepatitis B virus infection status from a single blood center in China

Background

When employing the transcription-mediated amplification method for screening blood donors, there are some non-discriminatory reactive results which are screening assay reactive but HBV-DNA discriminatory assay negative. This raises concerns regarding the possibility of false positives among donors, which may lead to permanent deferral of blood donors and affect blood supply. This study aimed to elucidate the infection status of these non-discriminatory reactive blood donors and develop and validate a model to predict individualized hepatitis B status to establish an optimal screening strategy.

Methods

Supplementary tests were conducted on initial non-discriminating reactive donations to determine their HBV infection status, including repeat testing, viral load, serological marker detection, and follow-up. Primary clinical variables of the donors were recorded. Based on the Akaike information criterion, a stepwise forward algorithm was used to identify the predictive factors for information and construct a predictive model. The optimal screening strategy was determined through cost-effectiveness analysis.

Results

At the Blood Center of Zhejiang Province, 435 cases of initial non-discriminatory reactive donations were collected over two successive periods and sub-categorized through repeated testing into the following three groups: non-repeated positive group, non-discriminated positive group, and non-repeated HBV-DNA positive group. The HBV discriminatory rate increased after repeated testing (110/435, 25.29%). According to supplementary tests, the HBV-DNA positivity rate was 65.52% (285/435), and occult HBV infection was a significantly different among groups (χ2 = 93.22, p < 0.01). The HBV serological markers and viral load in the non-repeated positive group differed from those in the other two groups, with a lower viral load and a higher proportion of false positives. The predictive model constructed using a stepwise forward algorithm exhibited high discrimination, good fit, high calibration, and effectiveness. A cost-effectiveness analysis indicated that utilizing repeated discriminatory testing and the predictive model is an extremely beneficial screening approach for non-discriminatory reactive blood donors.

Conclusion

Nearly two-third (65.52%) of the non-discriminatory reactive blood donors were HBV-DNA positive. Our innovative approach of constructing a predictive model as a supplementary screening strategy, combined with repeated discriminatory experiments, can effectively identify the infection status of non-discriminatory reactive blood donors, thereby increasing the safety of blood transfusions.

The importance of confirmatory assays in testing blood donors for human T-cell lymphotropic virus

BACKGROUND AND OBJECTIVES

Serological HTLV-1/2 screening is mandatory for blood donor candidates in Brazil. Our objective was to analyse HTLV test results in blood donors submitted for screening and confirmatory assays in a Brazilian blood bank.

MATERIALS AND METHODS

Retrospective analysis (2017-2022) results of chemiluminescence immunoassays and confirmatory tests for HTLV-1/2 in reactive donors were performed. During the analysed period, three sets of assays were used: (1) Architect rHTLV-I/II + HTLV Blot 2.4 (Western blot [WB]); (2) Alinity s HTLV I/II Reagent Kit + INNO-line immunoassay (LIA) HTLV I/II Score (LIA); (3) Alinity + WB.

RESULTS

The analysed period comprised a total of 1,557,333 donations. The mean percentage of HTLV reactive donors using the Architect assay was 0.14%. With the change to the Alinity assay, that percentage dropped 2.3-fold (0.06%). The reactivity rate in the confirmatory tests (1064 samples) ranged from 13.5% to 30.2%, whereas 58.3%-85.9% of samples were non-reactive. The highest rates of positive (30.2%) and indeterminate (11.5%) results were seen using LIA. Considering all analysed samples, those with signal/cut-off ratio (S/CO) >50 were positive in confirmatory tests (positive predictive value, PPV = 100%), whereas samples with S/CO ≤6 are very unlikely to be truly positive (PPV = 0).

CONCLUSION

The use of the Alinity assay reduced the frequency of false-positive results. Confirmatory tests are important to identify true HTLV infection in blood donors, because more than 58% of initially reactive individuals are confirmed as seronegative. Categorizing S/CO values is useful for assessing the likelihood of true HTLV-1/2 infection.

Medication Deferrals in Blood Donors

Medication use is extremely common in blood donors. Blood centers use various methods to obtain a history of medication use, all of which have strengths and weaknesses. Some data are available to develop policies for medications that impact product quality, transmissible disease testing, and infectious risks. Many blood centers defer donors for use of a small number of highly teratogenic medications, as a precautionary measure. Others also defer for possible harms related to the pharmacologic effects of medications. However, a single exposure to a blood component containing medication, with immediate dilution in the recipient's blood stream, is a very different situation from ongoing use of medication in a patient, with steady state concentrations achieved over time. It is therefore highly unlikely that these effects are relevant for recipient safety.

"Why don't you want my poop?" Willing stool donor's experiences of being ineligible to donate intestinal microbiota

BACKGROUND

Blood collection agencies (BCAs) hosting stool (fecal or poo) donor programs report high rates of donor deferral. However, the impact of deferral on willing donors, in terms of personal well-being and future engagement with BCAs, remains unexplored. Accordingly, we surveyed those attempting to donate intestinal microbiota about their experience of being ineligible.

STUDY DESIGN AND METHODS

A total of 196 potential stool donors from Australia's BCA (>90% blood/blood product donors) completed the first stage of eligibility screening and then an online survey once notified of their ineligibility. Respondents reported motives for donating, perceptions of screening and improvements needed, experience of being told they are ineligible, and their feelings about this.

RESULTS

Over 80% of participants were ineligible to donate. Of those ineligible, 58% did not know why they were ineligible resulting in potentially future eligible donors being permanently lost. Motives (>5%) included helping others, being a human substance donor, understanding benefits, curiosity/novelty, and helping science/research. Participants identified they needed clear and timely information during screening and a specific reason for their ineligibility. Participants commonly experienced disappointment, confusion, and calm in response to being ineligible.

DISCUSSION

BCAs need strategies to mitigate the disappointment of ineligible donors, maintain satisfaction with BCAs, and preserve donor identity since many ineligible donors give multiple human substances. BCAs should provide more information about eligibility criteria during early screening stages to reduce disappointment and give personalized information about ineligibility to resolve the confusion. Offering alternative opportunities to give may reduce disappointment and increase ineligible donor engagement.

Is dual testing for hepatitis C necessary? Modelling the risk of removing hepatitis C antibody testing for Australian blood donations

BACKGROUND AND OBJECTIVES

Parallel testing of blood donations for hepatitis C virus (HCV) antibody and HCV RNA by nucleic acid testing (NAT) has been standard practice in Australia since 2000. Meanwhile, NAT technologies have improved, and HCV has become a curable disease. This has resulted in a significant reduction in the risk and clinical consequences of HCV transmission through transfusion. This study aimed to estimate the residual risk (RR) under various testing options to determine the optimal testing strategy.

MATERIALS AND METHODS

A developed deterministic model calculated the RR of HCV transmission for four testing strategies. A low, mid and high estimate of the RR was calculated for each. The testing strategies modelled were as follows: universal dual testing, targeted dual testing for higher risk groups (first-time donors or transfusible component donations) and universal NAT only.

RESULTS

The mid estimate of the RR was 1 in 151 million for universal dual testing, 1 in 111 million for targeted dual testing of first-time donors, 1 in 151 million for targeted dual testing for transfusible component donations and 1 in 66 million for universal NAT only. For all testing strategies, all estimates were considerably less than 1 in 1 million.

CONCLUSION

Antibody testing in addition to NAT does not materially change the risk profile. Even conservative estimates for the cessation of anti-HCV predict an HCV transmission risk substantially below 1 in 1 million. Therefore, given that it is not contributing to blood safety in Australia but consuming resources, anti-HCV testing can safely be discontinued.

Understanding Mothers' Experiences of Being Ineligible to Donate Their Milk to a Not-for-Profit Milk Bank

Background: Donor milk banks have strict donor screening criteria to ensure that donor milk is safe for premature or hospitalized babies. Yet little evidence is available to understand how potential donors, who are often breastfeeding their own infants, experience being ineligible ("deferred") to donate their milk to a milk bank. Materials and Methods: Interviews were conducted with 10 mothers who were permanently or temporarily deferred from donating to a large, not-for-profit milk bank in Australia. Interviews focused on becoming a donor and being deferred, meanings of deferral, impact of deferral on feeding own infant, and improving the deferral process. Results: Thematic analysis of interviews identified nine themes: (1) donation as a solution to wasting milk; (2) eligibility questions were acceptable and understandable; (3) more information early on allows self-deferral; (4) deferral is not always clear; (5) deferral is disappointing but does not prevent future donation; (6) deferral did not prevent feeding own infant; (7) early information enables preparation for donation; (8) slow communication disrupts perfect timing to donate; and (9) alternatives to wasting milk. Conclusions: Milk banks have a duty of care to both milk recipients and donors. While mothers who want to donate milk are disappointed by deferrals, clear communication protects their breastfeeding relationships with their own infants. Milk banks can improve their screening processes by providing information up-front and ensuring timely contact with mothers. Mothers can then make informed decisions about donating and not feel as if their milk and resources are "wasted."

Re-Entry Evaluation of Chinese Blood Donors with Unconfirmed Hepatitis B Screening Results

The hepatitis B virus (HBV) remains a high priority for Chinese blood banks due to the high prevalence of infection. HBV blood safety has been significantly improved by the implementation of highly sensitive and specific serological and molecular HBV screening assays. The multiplication of viral markers tested and the ever-increasing analytical sensitivity of the tests can make the interpretation of the results difficult. False-positive or indeterminate results may lead to permanent donor deferrals and conflicts between donors and blood banks. To avoid blood shortages, blood services aim to limit unnecessary donor losses by developing procedures for the re-entry of donors temporarily deferred due to an unconfirmed HBV reactivity. The development of such procedures based on donor follow-up and HBV confirmation remains limited. A review of the scarce data available revealed considerable heterogeneity in testing methods and re-entry algorithms, limited validation studies, and a lack of accurate assessment of the residual infectious risk potentially associated with donor re-entry. In conclusion, systematic and widely validated confirmatory testing and prolonged follow-up are essential for safe re-entry of temporary deferred donors. Standardization of HBV testing methods and the establishment of dedicated expert laboratories are needed because of the complexity of HBV infection in blood donors.

Improved detection of hepatitis C virus-positive blood donors and determination of infection status

BACKGROUND

In low-risk populations, variability in the sensitivity of current serological tests for Hepatitis C virus (HCV) blood donor screening may lead to the presence of false-positive results. This contributes to the unnecessary loss of blood donor samples as well as to difficulty in accurate donor counselling. The present study determined the optimal cut-off value of a chemiluminescent immunoassay for identification of HCV-reactive blood donors.

STUDY DESIGN AND METHODS

In a retrospective cross-sectional analysis of 193 973 blood donations, 578 samples that were positive for HCV antibody in a chemiluminescent immunoassay and/or RNA screening tests were identified. Blood from 379 of these positive samples was available for retesting by a second confirmatory HCV immunoassay followed by a receiver operating characteristic (ROC) curve analysis. Donors were also recalled for a new analysis.

RESULTS

Only 71 (18.7%) blood samples remained HCV-positive upon retesting, while 233 (61.5%) now tested negative and 75 (19.8%) yielding indeterminate results. A signal to cutoff ratio ≥4.32 was determined as the best differential threshold between a positive and negative result, increasing the positive predictive value from 27.3% to 66.7%.

CONCLUSION

Using a higher threshold for an HCV-positive blood sample enhances the chemiluminescent immunoassay screening test´s accuracy and helps to improve donor counselling and notification processes.

Donor and recipient safety in human milk banking

AIM

Australian Red Cross Lifeblood supplies pasteurised donor human milk (PDHM) to more than 30 partner hospitals across Australia. Preterm infants who receive PDHM are a highly vulnerable population but formal biovigilance programs are rare in human milk banking. Lifeblood Milk performs ongoing surveillance for both donor and recipient adverse events. This study aimed to formally review adverse events reported to Lifeblood Milk since 2018.

METHODS

Milk donor infectious diseases testing outcomes and donor adverse events (DAEs) are prospectively recorded at Lifeblood. Infant recipient adverse events are contractually reported back to Lifeblood Milk by hospitals and assessed according to severity and likelihood of relationship to PDHM administration. Donor and recipient adverse events over a 3.5-year period (July 2018 to December 2021) were reviewed.

RESULTS

There were three DAEs (3/976 = 0.31%) related to phlebotomy; these included two vasovagal reactions and one phlebotomy site haematoma. Eight (8/976 = 0.81%) additional donors had biological false reactive (BFR) infectious diseases serology results. There were 10 reported suspected adverse events in recipients. Six were infection-related; other events included milk curd obstruction, high urinary iodine levels, sudden cardiac death and nasogastric tube obstruction. All reported suspected adverse events in recipients were classified as unlikely to be related, or definitely not related, to PDHM administration.

CONCLUSIONS

Milk donor adverse events were rare but biological false reactive serology results were not uncommon. There were no recipient adverse events considered causally related to pasteurised donor human milk, which is generally a low-risk biological product. Ongoing biovigilance remains essential.

Donor notification of permanent deferral: a qualitative study on the perceptions and practices of notifier and blood donor in Mexico

BACKGROUND

Informing about permanent deferral requires a process that links the notifier with the donor in a particular way. Little is known about the type of information and how it is disclosed to the donors. The current study aimed to examine perceptions and practices of notifier and blood donor within the framework of the notification process of permanent deferral and from the perspective of the notifier-blood donor relationship.

METHODS

A qualitative study with in-depth interviews. The participants were 13 notifiers and 25 permanently deferred donors. Participants were recruited from a national blood bank and a state's blood bank. The entire dataset/narratives were analysed using the method of thematic analysis.

RESULTS

The disclosure of permanent deferral was understood as a matter of disclosing the serological test results and their medical meaning along with a concise explanation of the deferral status with regard to future blood donation and the plan to be followed. The notifiers preferred to act in accordance with the standard protocol despite acknowledging the adverse psychological and social effects to which donors are exposed when they are informed of the possible disease and the consequent permanent deferral. Donors described a variety of psychological and social affectations. They valued honesty in the communication, the clarity of the information provided and a greater involvement of the notifier.

CONCLUSION

Even though the notification process does not imply that medical care is being offered to donors, the notifier is the administrator of the well-being of the donor. Notification must not be considered as something apart from care, since it is intimately related to the health of each of the donors and their medical care.

An Interesting Case of Isolated False-Reactive Hepatitis B Surface Antigen

The standard serologic markers used to diagnose hepatitis B infection include hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), total hepatitis B core antibody (anti-HBc), and IgM antibody to hepatitis B core antigen (IgM anti-HBc). Different markers or combinations of markers are used to identify different phases of HBV infection and determine whether a patient has acute or chronic infection or immunity due to prior infection or vaccination or is seronegative and susceptible to future infection. Isolated HBsAg seropositivity is a peculiar serological pattern that requires investigation. Herein, we present a case of an asymptomatic female without a history of liver disease or evident risk factors for hepatitis, who underwent screening for infectious disease prior to resection of basal cell carcinoma involving her eyelid. The patient's laboratory testing showed positivity for HBsAg and the HIV 1/2 screen. To investigate, we performed serial dilutions, utilized heterophilicantibody blocking tubes, and repeated analysis using a different commercial assay (Abbott Architect i2000), all in support of a false-positive result attributed to a heterophilic antibody. Hence, we demonstrate that heterophilic antibody interference can result in isolated HBsAg positivity and recommend considering this form of interference in the differential where there is low clinical suspicion for viral infection.

Qualification of the Geenius HIV 1/2 supplemental assay for use in the HIV blood donation screening algorithm

BACKGROUND

A single, simplified approach for human immunodeficiency virus (HIV)-1/HIV-2 antibody confirmation/differentiation is needed for the HIV blood donation supplemental algorithm used in the United States. A clinical evaluation of the Geenius assay was performed-the same assay used for HIV diagnostic confirmation/differentiation in the United States since 2014.

STUDY DESIGN AND METHODS

Well-characterized unlinked donation samples classified as HIV negative, false positive, or confirmed positive were included in the study: 200 antibody-nonreactive, 200 HIV-1 immunofluorescence assay (IFA) confirmed-positive, and 100 antibody-screen false-positive donations, equally divided between serum and plasma. Samples were retrieved from a repository, relabeled, and tested by an immunochromatographic test (Geenius HIV 1/2 Supplemental Assay, Bio-Rad). Comparator testing involved parallel US Food and Drug Administration (FDA)-licensed HIV-1 IFA or HIV-2 enzyme immunoassay (EIA) supplemental testing for any sample missing those results as part of routine testing (otherwise test-of-record results were used). Samples with discordant results were further tested with a rapid test (Multispot HIV-1/HIV-2 Rapid Test, Bio-Rad) to provide final sample interpretations. Testing volume reductions with the Geenius were estimated from screening performed by the American Red Cross from September 2016 to April 2019.

RESULTS

Clinical results were 100% sensitivity and specificity with an indeterminate rate of 4.0% to 5.0%. From 2016 to 2019, sole use of the Geenius would reduce testing complexity for 5265 antibody repeat-reactive donations including 95.7% (5028) false positives, eliminating approximately 5000 unnecessary tests.

CONCLUSION

Geenius FDA licensure (August 26, 2019) adding the HIV-1/HIV-2 differentiation/confirmation donation supplemental claim will enable replacement of previously used FDA-licensed supplemental assays while maintaining comparable sensitivity, avoiding thousands of unnecessary HIV-1-IFA, western blot, and HIV-2-EIA tests.

Follow-up program for blood donors with unconfirmed screening results reveals a high false-positive rate in Dalian, China

BACKGROUND

Chinese blood donors with unconfirmed serological and/or molecular screening results are deferred permanently. This study investigated the implementation and performance of a follow-up program aiming to improve the notification and management of deferred donors in Dalian, China.

STUDY DESIGN AND METHODS

From January 2013 to February 2018, 411,216 donations were tested for HBsAg, anti-HCV, anti-HIV/HIV antigen, and antibodies to Treponema pallidum. HBV, HCV, and HIV nucleic acid testing (NAT) was performed in mini-pools of six or in individual donations (IDs). Reactive donations were evaluated further with alternative serological assays and ID-NAT re-testing. A follow-up procedure was developed to evaluate a subset of deferred donors that were either potential NAT yield cases, serology non-reactive and NAT non-repeated reactive (NRR), or serology NRR irrespective of NAT result.

RESULTS

Serological and molecular routine, plus supplemental testing, identified HBV, HCV, HIV, and TP in 503 (0.12%), 392 (0.09%), 156 (0.04%), and 2041 (0.49%) donations, respectively. Overall, 683 of 4156 (16.4%) eligible donors and 205 donors deferred prior 2013 participated in the program. They included 664 serology NRR and 224 NAT yield cases, and 58.8% repeat donors. All markers combined, follow-up documented false reactivity, primary acute infections, and OBI in 61.9% (550/888), 3.3% (29/888), and 12.8% (114/888) of these donors, respectively. Isolated anti-HBc or anti-HBs reactivity was observed in 22% of cases.

CONCLUSION

Follow-up testing refined infection status in 78.0% (693/888) of deferred donors with unconfirmed screening results. This high false-positive rate encouraged to reevaluate the current screening strategies and to consider donor reentry.

High rate of hepatitis C virus and human immunodeficiency virus false-positive results in serologic screening in sub-Saharan Africa: adverse impact on the blood supply

BACKGROUND

False positivity in blood screening may cause unnecessary deferral of healthy donors and exacerbate blood shortages. An international multicenter study was conducted to estimate the frequency of HCV and HIV false seropositivity in seven African countries (Burundi, Cameroon, Democratic Republic of Congo, Madagascar, Mali, Mauritania, and Niger).

STUDY DESIGN AND METHODS

Blood donations were tested for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) with rapid detection tests (RDTs), third-generation enzyme immunoassays (EIAs), or fourth-generation EIAs. HCV (456/16,613 [2.74%]) and HIV (249/16,675 [1.49%]) reactive samples were then confirmed with antigen/antibody assays, immunoblots, and nucleic acid testing. Partial viral sequences were analyzed when possible.

RESULTS

The HCV reactivity rate with RDTs was significantly lower than with EIAs (0.55% vs. 3.52%; p < 0.0001). The HIV reactivity rate with RDTs was lower than with third-generation EIAs (1.02% vs. 2.38%; p < 0.0001) but similar to a fourth-generation assay (1.09%). Only 16.0% (57/357) and 21.5% (38/177) of HCV and HIV initial reactive samples, respectively, were repeatedly reactive. HCV and HIV infections were confirmed in 13.2% and 13.7%, respectively, of repeated reactive donations. The predominant HCV genotype 2 and 4 strains in West and Central Africa showed high genetic variability. HIV-1 subtype CRF02_AG was most prevalent.

CONCLUSION

High rates (>80%) of unconfirmed anti-HCV and anti-HIV reactivity observed in several sub-Saharan countries highlights the need for better testing and confirmatory strategies for donors screening in Africa. Without confirmatory testing, HCV and HIV prevalence in African blood donors has probably been overestimated.

Consecutive reactive results in screening of transfusion transmitted infections: Family history of blood donors is also important

BACKGROUND

Enzyme linked immunosorbent assay (ELISA) test is used for screening of transfusion transmitted infections (TTI) in blood donors. Consecutive reactive results in ELISA is due to sample/reagent carryover or donor related. In this study we tried to find out the possibilities of family history/close contacts with patients of hepatitis among these consecutive reactive donors.

AIM

To analyze the consecutive reactive results in ELISA tests for TTI testing on samples of healthy blood donors.

MATERIAL AND METHODS

A retrospective observational study was conducted from January 2016 to July 2018 in a tertiary care hospital, North India. Consecutive reactive results by fourth generation ELISA for TTIs screening were evaluated for possible reasons. Confirmation tests were not done. Reactive donors were contacted telephonically for relevant history of close contact with infected personnel.

RESULTS

Out of 53,740 donations 1,061 were reactive for TTIs during our study period. Prevalence of Hepatitis B (HBV), Human Immunodeficiency (HIV) and Hepatitis C (HCV) virus infection in blood donors were 1.27%, 0.20% and 0.50% respectively. Consecutive reactive results for HBV were 9.20% (63/685), for HCV 6.0% (16/266) and nil for HIV. There was no sample carryover in this. Out of 79 consecutive reactive donors 69 donated for same patients and 32 were related with infected patient which are statistically significant (p < 0.0001).

DISCUSSION

This study recommends that in analysis of consecutive positive results in ELISA along with looking for procedure/sample error, there is also a need to take retrospective history of donors for close contact with infected patients.