Sporadic Hepatitis A Virus PCR False-Positive Results Observed during Reflex Testing of Serum Samples Previously Tested for Anti-HAV Antibodies and Caused by Contamination with HAV RNA Present in the Reagents of the Commercial Anti-HAV Immunoassay

Hepatitis A diagnosis relies on serology and occasionally on hepatitis A virus (HAV) RNA detection. For timely diagnosis and the avoidance of drawing additional blood, molecular testing is often performed as reflex testing by using blood specimens that were initially sent for anti-HAV serology. Reflex molecular testing is preferably performed from different sample aliquots, but, for limited sample quantities, it uses samples that have been preprocessed in an immunoassay analyzer. In 2012, we first observed sporadic HAV RNA-positive cases that were inconsistent with patients' serological profiles and/or medical histories, suggesting that occasional laboratory contamination was causing false-positive PCR results. Multiple external quality assurance (EQA) and laboratory surface contamination checks were performed, questionable specimens were tested with various HAV RNA tests, and follow-up serum/stool samples were collected. All contamination-check samples and samples from healthy individuals tested HAV RNA-negative, and the laboratory successfully passed all EQAs. The HAV RNA-positive results were reproducible with various HAV RNA assays. No patients seroconverted, and their follow-up samples were consistently HAV RNA-negative. Finally, a detailed review of testing protocols revealed a correlation between HAV RNA false positivity and preceding anti-HAV testing with the Cobas-e411 automated immunoassay analyzer. HAV RNA was detected in the Cobas-e411 anti-HAV reagents, with the HAV sequences matching those from the false-positive samples. Preceding anti-HAV testing using two other immunoassay analyzers did not result in subsequent HAV RNA false positivity during reflex testing. The Cobas-e411 pipetting procedure with a single pipette tip collecting samples and anti-HAV reagents contaminated the original sample with the HAV RNA that was present in the immunoassay's reagents, thereby resulting in HAV RNA false positivity during the reflex testing. IMPORTANCE We present the first report of sporadic HAV PCR false-positive results that have been observed during the reflex testing of serum samples that have previously been tested for anti-HAV antibodies and have been caused by contamination with HAV RNA that is present in the reagents of the commercial anti-HAV immunoassay, with potentially serious clinical consequences. Although HAV RNA was consistently detected in the anti-HAV reagents of all three automated immunoassay analyzers that were in use in our laboratory, only the use of one analyzer and the corresponding commercial anti-HAV immunoassay reagents resulted in contamination that led to false positive HAV RNA results, and this was due to a peculiar pipetting mode of action in which the analyzer uses a single pipette tip to collect both anti-HAV reagents and a sample, which consequently causes the permanent contamination of the original sample with HAV RNA. Manufacturers should strongly consider the occasional need for reflex molecular testing from preprocessed samples and design their analyzers in a way that prevents contamination.

Hepatitis A virus (HAV) RNA detection in Polish blood donors and likely transmissions through blood components during the 2017-2019 epidemic

BACKGROUND

In Poland, hepatitis A virus (HAV) RNA screening was performed in plasma for fractionation usually immediately before shipment.

OBJECTIVE

Our goal was to study epidemiology, rate of transfusion transmitted HAV during epidemic (2017-2019), and viral characteristics of infected plasma donors.

STUDY DESIGN AND METHODS

HAV RNA was tested in 1,866,590 donations from 1,210,423 donors using RT-PCR in mini pools of 96 (MP96) or TMA in MP16. Virological characteristics included RNA level (RL), antibody testing, and sequencing.

RESULTS

Twenty-one HAV infections were identified (1.13/100,000 donations; 95% confidence interval [95% CI]: 0.74-1.72) and (1.73/100,000 donors; 95% CI: 1.35-2.65). The Blood Transfusion Centers were also informed about three donors, who were hospitalized for hepatitis A soon after their blood donation. In addition, we identified a donor, who had reactive result for HAV after receiving HAV vaccination. He tested positive twice 10 days after receiving the first and the second dose. The highest RL was 16 million IU/ml, mean 1,706,905 IU/ml, and median 220 IU/ml. The longest detectable RL lasted for 113 days. HAV-infected donors were seronegative (36%) or IgM positive (64%). We followed up on 12 HAV contaminated blood components issued for transfusion. In two out of seven identified patients viral transmission was confirmed (28.6%).

CONCLUSION

Based on our results, we propose a 6 month deferral after HAV infection and 14 days post HAV vaccination. The infectivity rate was below 30%. The HAV RNA testing could be considered as an additional safeguard against HAV transmission at the time of increased incidence of HAV infections in the general population.

RNA testing for the diagnosis of acute hepatitis A during the 2017 outbreak in France

Diagnostic of acute hepatitis A virus (HAV) infection is based on the detection of anti-HAV IgM without testing for the pathogen itself. We evaluated the usefulness of HAV RNA testing for confirmation of acute hepatitis A and to provide indications about the level of HAV replication in HIV-positive and HIV-negative subjects during an unprecedented outbreak of HAV observed in France in 2017. HAV RNA was detected in 38 out of 41 (92.6%) subjects with a clinical diagnosis of acute hepatitis A, whereas nine cases tested positive for anti-HAV IgM in whom the diagnosis of acute hepatitis A was not retained were found negative for HAV RNA. All subjects in the control group were also tested negative for HAV RNA. HAV viremia was correlated to ALT peak (r = .64; P < .0001). HIV-infected patients have similar HAV RNA levels but were less likely to have prolonged international normalized ratio of prothrombin time when compared to the HIV-uninfected group (P = .016), suggesting a less severe course of acute hepatitis. HAV RNA was detected in the serum of most of the patients with acute hepatitis A, indicating that the direct detection of HAV can be used to confirm hepatitis A in patients tested positive for anti-HAV IgM antibodies. Nucleic acid tests should serve more broadly during the diagnosis workup of acute hepatitis A to improve the predictive values of HAV in vitro diagnostic tests and to confirm acute hepatitis A in patients tested positive with IgM with moderate or low S/CO values.

[Markers of hepatitis A in the monkeys of the Adlers primate center.]

Hepatitis A is a widespread viral infection. The HAV strains of "human" and "monkey" origin are similar in their morphological and antigenic properties, but differ genotypically.

OBJECTIVES

The aim of this research was a comparative study of serological and molecular-genetic markers of HAV infection in monkeys born at the Adler Primate Center and in those imported from different countries.

MATERIAL AND METHODS

Fecal samples (n = 313) and serum (n = 266) from various species of monkey using ELISA and RT-PCR were studied.

RESULTS AND DISCUSSION

The frequency of anti-HAV-IgG was high (78.9%) in imported animals (vervet monkeys from Tanzania and cynomolgus monkeys from Vietnam) and as well as in various species of monkeys (rhesus monkeys, cynomolgus monkeys, green monkeys and papio hamadryas) of the Center (88.6%). At the same time, in the imported monkeys, the markers of "fresh" HAV infection (IgM-27.2%, Ag-HAV-16.7%, RNA-22.0%) were detected significantly more often (p> 0.05) than in monkeys kept at the Colony (IgM-7.5%, HAV-Ag - 5.2%, RNA - 3.6%). In general, anti-IgG reactivity ranged from 1.064 to 2.073 OD₄₅₀, anti-IgM ranged from 0.546 to 1.059 OD₄₅₀. The number of HAV-Ag was 0.496 - 1.995 OD₄₅₀. RNA HAV only in rhesus monkeys and cynomolgys monkeys born at the Colony, as well as in imported vervet monkeys was detected.

CONCLUSIONS

The data obtained indicate a wide circulation of HAV among monkeys born in the Adler Primate Center and among the imported animals. Markers of "fresh" HAV infection varied depending on the species of monkeys and their origin.