A group of 126 German nationals was evacuated from Wuhan to Frankfurt after screening for symptoms of Covid-19 and was to undergo a 14-day quarantine and additional screening in Frankfurt. The ...authors discovered evidence of SARS-CoV-2 infection in throat swabs from 2 evacuated persons who had passed the symptoms-based screening.
Testing for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by RT-PCR is a vital public health tool in the pandemic. Self-collected samples are increasingly used as an alternative to ...nasopharyngeal swabs. Several studies suggested that they are sufficiently sensitive to be a useful alternative. However, there are limited data directly comparing several different types of self-collected materials to determine which material is preferable. A total of 102 predominantly symptomatic adults with a confirmed SARS-CoV-2 infection self-collected native saliva, a tongue swab, a mid-turbinate nasal swab, saliva obtained by chewing a cotton pad and gargle lavage, within 48 h of initial diagnosis. Sample collection was unsupervised. Both native saliva and gargling with tap water had high diagnostic sensitivity of 92.8% and 89.1%, respectively. Nasal swabs had a sensitivity of 85.1%, which was not significantly inferior to saliva (
= 0.092), but 16.6% of participants reported they had difficult in self-collection of this sample. A tongue swab and saliva obtained by chewing a cotton pad had a significantly lower sensitivity of 74.2% and 70.2%, respectively. Diagnostic sensitivity was not related to the presence of clinical symptoms or to age. When comparing self-collected specimens from different material, saliva, gargle lavage or mid-turbinate nasal swabs may be considered for most symptomatic patients. However, complementary experiments are required to verify that differences in performance observed among the five sampling modes were not attributed to collection impairment.
•Comparison of the most widely used commercially available SARS-CoV-2 RNA tests.•The NAT assays examined showed a comparable sensitivity/specificity when testing clinical and EQA (External Quality ...Assessment) samples.•N gene-based assays demonstrated the highest sensitivity in the serial dilution panel.
Multiple nucleic acid amplification tests (NATs) are available for the detection of SARS-CoV-2 in clinical specimens, including Laboratory Developed Tests (LDT), commercial high-throughput assays and point-of-care tests. Some assays were just recently released and there is limited data on their clinical performance. We compared the Xpert® Xpress SARS-CoV-2 (Cepheid) and Vivalytic VRI Panel (Schnelltest COVID-19) (Bosch) point-of-care tests with four high-throughput assays and one LDT, the cobas® SARS-CoV-2 test (Roche), the Allplex™ 2019-nCoV Assay (Seegene), the SARS-CoV-2 AMP (Abbott) Kit, the RealStar® SARS-CoV-2 RT-PCR Kit 1.0 (altona) as well as an assay using a SARS-CoV-2 RdRP gene specific primer and probe set. Samples from patients with confirmed SARS-CoV-2 infection, samples from the first and second SARS-CoV-2-PCR External Quality Assessment (EQA) (INSTAND e.V.) and a 10-fold serial dilution of a SARS-CoV-2 cell culture (SARS-CoV-2 Frankfurt 1) supernatant were examined. We determined that the NAT assays examined had a high specificity. Assays using the N gene as target demonstrated the highest sensitivity in the serial dilution panel, while all examined NAT assays showed a comparable sensitivity when testing clinical and EQA samples.
Background: To minimize the risk of disease transmission in cornea transplantation, donor screening for blood-derived viral infections is mandatory. Ideally, pre-mortem blood samples are used, but ...based on availability, cadaveric blood samples of cornea donors may also be used. However, serological and nucleic acid amplification tests (NATs) need to be validated for the use of cadaveric specimens. Methods: Hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV) 1/2, and Treponema pallidum (syphilis)-specific serological and/or NAT assays were validated on different platforms (Abbott Alinity i, Alinity m, Roche Cobas 6800, and Roche Cobas AmpliPrep/Cobas TaqMan (CAP/CTM)) using (un)spiked paired pre- and post-mortem cornea donor blood samples from the same individual (up to 23.83 h after death) of 28 individuals in accordance with the specifications of the German Federal Institute for Vaccines and Biomedicines (Paul-Ehrlich-Institut PEI). In addition, routinely HBV-, HCV- and HIV-PCR-negative tested post-mortem blood samples of 24 individuals were used to assess NAT specificity. Results: For the majority of serological parameters on the Abbott Alinity i (HBsAg, anti-HBc, anti-HBs, anti-HCV, anti-HIV, anti-HTLV 1/2, and anti-Treponema pallidum), ratios of generated test results of (un)spiked paired pre- and post-mortem blood samples differed ≤25%, with an agreement of qualitative pre- and post-mortem test results ranging from 91.2 to 100%. For NAT parameters (HBV, HCV, and HIV) on the Cobas 6800, Alinity m, and CAP/CTM, no significant deviation in virus concentrations (factor >5) of spiked pre- and post-mortem blood samples could be observed. Ct-values of corresponding internal controls did also not differ significantly (>1.5 Ct-values). In addition, no false-positive test results were generated when specificity was assessed. Conclusion: Overall, fluctuations of test results for serological and NAT parameters in pre- and post-mortem blood samples examined in this study, were only limited and within the range of what is also observed when routinely testing fresh patient specimens. We conclude that all examined assays are eligible for the screening of blood samples taken up to about 24 h after the occurrence of death.
Abstract This review summarizes major issues of verification and validation procedures and describes minimum requirements for verification and validation of diagnostic assays in clinical virology ...including instructions for CE/IVD-labeled as well as for self-developed (“home-brewed”) tests or test systems. It covers techniques useful for detection of virus specific antibodies, for detection of viral antigens, for detection of viral nucleic acids, and for isolation of viruses on cell cultures in the routine virology laboratory.
In den letzten zwei Jahrzehnten hat die Diagnostik viraler Infektionen wesentlich an Bedeutung gewonnen. Neben kostengünstigen Untersuchungen ist es insbesondere für den Arzt und die Patienten ...wichtig, schnelle und richtige Untersuchungsergebnisse von den Laboratorien zu erhalten. Die Richtigkeit der Untersuchungsergebnisse hängt von verschiedenen Faktoren ab. Besonders wichtig ist die Eignung und Leistungsfähigkeit des benutzten Tests bzw. Untersuchungsverfahrens.
Gemäß der DIN EN ISO 15189 „Medizinische Laboratorien – besondere Anforderungen an die Qualität und Kompetenz“ und der In-vitro-Diagnostika-Richtlinie dürfen nur Tests bzw. Untersuchungsverfahren eingesetzt werden, deren Eignung und Leistungsfähigkeit ermittelt und nachgewiesen wurde.
Die Darlegung der Eignung und Leistungsfähigkeit – die so genannte Validierung – wird allerdings in beiden Dokumenten nur in allgemeiner Form angesprochen. Für den Bereich der Virusdiagnostik wurde daher ein Leitfaden erstellt, in dem die Mindestanforderungen an die Validierung konkretisiert werden. Dabei wird zwischen kommerziellen CE-gekennzeichneten Tests und In-house-Tests sowie zwischen den verschiedenen in der Virusdiagnostik zur Anwendung kommenden Methoden unterschieden.
During the last two decades the laboratory diagnostics of virus infections has achieved essential importance. In addition to low-cost examinations, it is important for the doctor and patient to obtain fast and correct laboratory results. The correctness of the results depends on different factors. The suitability and efficiency of the test and/or examination procedure under consideration are of particular importance.
According to the ISO 15189 “Medical laboratories – special requirements for quality and competence” and the guideline for in vitro diagnostic medical devices (IvD Directive) only tests and/or examination procedures may be used for which suitability and capability could be demonstrated. Requirements for suitability and efficiency or the so-called validation is only generally addressed in both documents.
Therefore, a guideline for virus diagnostics has been developed where the requirements for validation are described in detail. The guideline distinguishes between the validation of commercial tests, in-house tests, and the different examination methods used in virus diagnostics.
Zusammenfassung In den letzten zwei Jahrzehnten hat die Diagnostik viraler Infektionen wesentlich an Bedeutung gewonnen. Neben kostengünstigen Untersuchungen ist es insbesondere für den Arzt und die ...Patienten wichtig, schnelle und richtige Untersuchungsergebnisse von den Laboratorien zu erhalten. Die Richtigkeit der Untersuchungsergebnisse hängt von verschiedenen Faktoren ab. Besonders wichtig ist die Eignung und Leistungsfähigkeit des benutzten Tests bzw. Untersuchungsverfahrens. Gemäß der DIN EN ISO 15189 „Medizinische Laboratorien – besondere Anforderungen an die Qualität und Kompetenz“ und der In-vitro-Diagnostika-Richtlinie dürfen nur Tests bzw. Untersuchungsverfahren eingesetzt werden, deren Eignung und Leistungsfähigkeit ermittelt und nachgewiesen wurde. Die Darlegung der Eignung und Leistungsfähigkeit – die so genannte Validierung – wird allerdings in beiden Dokumenten nur in allgemeiner Form angesprochen. Für den Bereich der Virusdiagnostik wurde daher ein Leitfaden erstellt, in dem die Mindestanforderungen an die Validierung konkretisiert werden. Dabei wird zwischen kommerziellen CE-gekennzeichneten Tests und In-house-Tests sowie zwischen den verschiedenen in der Virusdiagnostik zur Anwendung kommenden Methoden unterschieden.
Abstract During the last two decades the laboratory diagnostics of virus infections has achieved essential importance. In addition to low-cost examinations, it is important for the doctor and patient to obtain fast and correct laboratory results. The correctness of the results depends on different factors. The suitability and efficiency of the test and/or examination procedure under consideration are of particular importance. According to the ISO 15189 “Medical laboratories – special requirements for quality and competence” and the guideline for in vitro diagnostic medical devices (IvD Directive) only tests and/or examination procedures may be used for which suitability and capability could be demonstrated. Requirements for suitability and efficiency or the so-called validation is only generally addressed in both documents. Therefore, a guideline for virus diagnostics has been developed where the requirements for validation are described in detail. The guideline distinguishes between the validation of commercial tests, in-house tests, and the different examination methods used in virus diagnostics.
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