Qualification of serological infectious disease assays for the screening of samples from deceased tissue donors

Serological testing on the ADVIA Centaur system for human immunodeficiency virus, hepatitis B virus and hepatitis C virus in specimens from deceased and living individuals demonstrates equivalent resultsƚ

Introduction

To determine the suitability of human tissues and cells for transplantation, guidelines mandate infectious disease testing of serum or plasma obtained from deceased donors, which are often collected after cessation of the heartbeat. Tests used for this purpose are required to show equivalent performance when compared to pre‐mortem specimens. This study evaluated whether serology assays for HIV Ag/Ab Combo, hepatitis B virus (HBc Total; HBsAgII), and HCV on the ADVIA Centaur system, were fit for testing post‐mortem sera. Performance evaluation studies included precision, specificity, and sensitivity.

Methods

Blood specimens were collected within 24 h after death from 82 deceased and 83 healthy living individuals. Studies followed standard guidelines. The 20‐day precision study was performed on five levels of post‐mortem specimens (non‐spiked and spiked). The specificity study compared 81–83 pre‐mortem and 74–82 post‐mortem specimens. The sensitivity study compared 50 pre‐mortem and 50 post‐mortem specimens spiked with positive sera for each analyte at two levels to achieve a low (near cutoff) positive result and a second higher positive result.

Results

Precision, specificity, and sensitivity study results met acceptance criteria for all assays and lots; post‐mortem and pre‐mortem results were equivalent.

Conclusion

Based on this study, the ADVIA Centaur CHIV, HBcT, HBsAgII, and HCV assays are acceptable for use in routine testing of deceased donor sera collected after cessation of the heartbeat.

Validation of OraQuick HCV Rapid Antibody Test in Postmortem Specimens

INTRODUCTION

The objective of this study is to evaluate the performance of OraQuick HCV Rapid Antibody Test against a "gold-standard", FDA-approved, laboratory-based serum immunoassay (SI) in postmortem blood. To date, OraQuick HCV Rapid Antibody Test has not been evaluated for use in postmortem testing. This OraQuick test is a manually performed, visually interpreted, single use immunoassay for the qualitative detection of antibodies to the hepatitis C virus (HCV).

METHODS

Blood was collected from 51 decedents whose deaths were investigated in the jurisdiction of the Knox and Anderson County Medical Examiner's Office (MEO) January 2017 through April 2017. For each consented case, blood was tested using both the OraQuick HCV Rapid Antibody Test and a laboratory-based hepatitis C serum immunoassay ("gold standard" reference assay). Results from the OraQuick HCV Rapid Antibody Test were compared against a laboratory-based hepatitis C serum immunoassay.

RESULTS

Using the laboratory-based serum immunoassay (SI) as the "gold standard" for assessing true HCV antibody positivity, and comparing SI against OraQuick rapid test, sensitivity for the OraQuick rapid test was 95.65% and specificity was 96.15% in postmortem blood.

DISCUSSION

Our results demonstrate that OraQuick HCV rapid antibody test is reliable for diagnosis of hepatitis C infection in postmortem blood with a relatively short (less than approximately 21.5 hours) postmortem sample acquisition time. The OraQuick in some cases may be superior to traditional, laboratory-based HCV SI due to potential increased viscosity of postmortem blood.

Validation of Spiked Postmortem Blood Samples from Cornea Donors on the Abbott ARCHITECT and m2000 Systems for Viral Infections

Background

Transplantation of human corneal tissue is associated with the potential risk of transmittance of viral infections. In accordance with European directives and federal laws, in Germany each tissue donor has to be tested for infectious diseases such as hepatitis B and C virus (HBV and HCV) and human immunodeficiency virus (HIV) infection. However, most of the currently available CE-marked serologic and nucleic acid screening systems are only validated for antemortem blood.

Methods

Twenty related and paired ante- and postmortem blood samples from cornea donors were obtained and subsequently analyzed for hepatitis B surface antigen (HBsAg), hepatitis B antibody (anti-HBc), anti-HCV, HCV RNA, anti-HIV-1/2, and HIV p24 Ag using Abbott test systems. The sera were also spiked with reference materials in concentrations giving low and high positivity for HBV, HCV, and HIV markers.

Results

The spiked ante- and postmortem sera from related donors showed similar results for HBsAg, anti-HBc, anti-HCV, HCV RNA, anti-HIV, and HIV p24 Ag, indicating a high stability of viral markers in cadaveric specimens. Three cornea donors had a medical history of HBV infection and revealed anti-HBc at similar levels in the ante- and postmortem sera. In addition, there was a single postmortem sample demonstrating a weak signal of anti-HIV-1 and HIV-1 p24 Ag. False-positive or false-negative results were not detected. The results obtained with the Abbott ARCHITECT analyzer and Abbott RealTime HCV PCR showed no significant differences.

Conclusion

The analyzed screening assays are suitable for the detection of infectious markers of HBV, HCV, and HIV at similar levels in spiked ante- and postmortem sera from cornea donors.

Detection of human immunodeficiency virus, hepatitis C virus, and hepatitis B virus in postmortem blood specimens using infectious disease assays licensed for cadaveric donor screening

BACKGROUND

Evaluation of assay performance on postmortem blood specimens (obtained after cessation of the heartbeat) presents unique scientific and regulatory challenges. In the United States, assay performance is evaluated in part by spiking postmortem specimens.

METHODS

Fifty-four specimens obtained from decedents known to be infected with human immunodeficiency virus (HIV), hepatitis C virus (HCV), or hepatitis B virus (HBV), including some coinfections, were tested for each virus using Food and Drug Administration (FDA)-licensed donor screening tests for nucleic acid, antibody, and antigen.

RESULTS

For each disease, >95% of subjects who were reported to have an infection at the time of death had a positive test result on at least one of the donor screening assays for that infection.

CONCLUSION

Licensed donor screening tests were positive on postmortem specimens obtained within 24 hours of death from individuals dying with HIV, HCV, and/or HBV, and were able to detect presence of the virus. The use of multiple tests (including antibody and direct viral detection methods) is necessary to adequately evaluate donors.

Effective serological and molecular screening of deceased tissue donors

A comprehensive and effective screening programme is essential to support the banking of tissues from deceased donors. However, the overall quality of the samples obtained from deceased donors, quantity and condition, is often not ideal, and this may lead to problems in achieving accurate and reliable results. Additionally a significant percentage of referrals are still rejected upon receipt as unsuitable for screening. We are actively involved in improving the overall quality of deceased donor screening outcomes, and have specifically evaluated and validated both serological and molecular assays for this purpose, as well as developing a specific screening strategy to minimise the specificity issues associated with serological screening. Here we review the nature and effectiveness of the deceased donor screening programme implemented by National Health Service Blood and Transplant (NHSBT), the organisation with overall responsibility for the supply of tissue products within England. Deceased donor screening data, serological and molecular, from August 2007 until May 2012 have been collated and analysed. Of 10,225 samples referred for serology screening, 5.5 % were reported as reactive; of 2,862 samples referred for molecular screening, 0.1 % were reported as reactive/inhibitory. Overall 20 % of the serological and 100 % of the molecular screen reactivity was confirmed as reflecting true infection. The use of a sequential serology screening algorithm has resulted in a marked reduction of tissues lost unnecessarily due to non-specific screen reactivity. The approach taken by NHSBT has resulted in the development of an effective and specific approach to the screening of deceased tissue donors.

Infectious disease screening of blood specimens collected post-mortem provides comparable results to pre-mortem specimens

Serology assays for standard screening are optimised for use with sera collected from living adults and children. Because of potential changes in the vascular compartments after death, methods used for screening sera from cadaveric organ donors need to be validated before testing these specimens. Serum was separated from blood collected from cadaveric donors within 24 h of death and biochemical parameters measured to detect dilution of protein and haemolysis. In order to demonstrate if any inhibitors that might interfere with the assays were present, pre and post-mortem specimens were spiked with aliquots of human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV), human T-cell Lymphotropic Virus (HTLV) and T. pallidum-positive sera. Comparison of serum from living subjects with serum obtained post-mortem showed that while the concentration of total protein decreased, concentrations of albumin, immunoglobulin G (IgG) and immunoglobulin M (IgM) remained unchanged. The degree of haemolysis, as measured by free haemoglobin, was within the limits accepted for the Architect analyser. Spiking of pre- and post-mortem specimens with aliquots of HIV, HCV, HBV, HTLV and T. pallidum-positive sera showed no statistical difference in the signal between pre-mortem and post-mortem results when tested on the Abbott Architect analyser. Positive results were obtained in each of a further nine subjects who had tested positive for HIV (n=1), HCV (n=8), HBV (n=1) on pre-mortem serological testing. These findings suggest that the sensitivity of the Abbott Architect serological screening tests is not significantly affected in specimens collected within 24 h of the cessation of life.

Testing the Donor

The transplantation of tissues from donor to recipient is a fundamental part of medicine today. A range of tissues including bone, skin, tendons, heart valves, corneas etc. are collected from suitable donors and transplanted into those patients for whom tissue transplant would have clinical benefit.