Sensitivity, Specificity and Predictive Values of Molecular and Serological Tests for COVID-19: A Longitudinal Study in Emergency Room

Bisoffi, Zeno; Pomari, Elena; Deiana, Michela; Piubelli, Chiara; Ronzoni, Niccolò; Beltrame, Anna; Bertoli, Giulia; Riccardi, Niccolò; Perandin, Francesca; Formenti, Fabio; Gobbi, Federico; Buonfrate, Dora; Silva, Ronaldo

doi:10.3390/diagnostics10090669

Cited by 39 publications

(46 citation statements)

References 41 publications

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“…First, we treat all positive tests as true positive. While errors may occur, the rate of false-positive results is very low 2–5 and we do not expect it to significantly affect our results. Future studies can further improve the reliability of confirmation of positive cases by combining PCR test results with serology tests.…”

Section: Discussionmentioning

confidence: 76%

Association of COVID-19 RT-qPCR test false-negative rate with patient age, sex and time since diagnosis

Levine-Tiefenbrun

Yelin

Uriel

et al. 2020

Preprint

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Background Routine testing for SARS-CoV-2 in the community is essential for guiding key epidemiological decisions from the quarantine of individual patients to enrolling regional and national preventive measures. Yet, the primary testing tool, the RT-qPCR based testing, is notoriously known for its low sensitivity, i.e. high risk of missed detection of carriers. Quantifying the false-negative rate (FNR) of the RT-qPCR test at the community settings and its dependence on patient demographic and disease progression is therefore key in designing and refining strategies for disease spread prevention. Methods Analyzing 843,917 test results of 521,696 patients, we identified false-negative (FN) and true-positive (TP) results as negative and positive results preceded by a COVID-19 diagnosis and followed by a later positive test. Regression analyses were used to determine associations of false-negative results with time of sampling after diagnosis, patient demographics and viral loads based on RT-qPCR Ct values of the next positive tests. Findings The overall FNR was 22.8%, which is consistent with previous studies. Yet, this rate was much lower at the first 5 days following diagnosis (10.7%) and only increased in later dates. Furthermore, the FNR was strongly associated with demographics, with odds ratio of 1.74 (95% CI: 1.58-1.9) for women over men and 2.54 (95% CI: 2.39-2.69) for a 20 versus a 50 year old patient. Finally, FNR was associated with viral loads (p-value 0.002), with a difference of 1.1 (95% CI: 0.60-1.57) between the average Ct of the N gene in a positive test following a false-negative compared to a positive test following a true-positive. Interpretation Our results show that in the first few days following diagnosis, when results are critical for quarantine decisions, RT-qPCR testing is more reliable than previously reported. Yet the reliability of the test result is reduced in later days as well as for women and younger patients, where the viral loads are typically lower. Funding This research was supported by the ISRAEL SCIENCE FOUNDATION (grant No. 3633/19) within the KillCorona-Curbing Coronavirus Research Program.

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Section: Discussionmentioning

confidence: 76%

Association of COVID-19 RT-qPCR test false-negative rate with patient age, sex and time since diagnosis

Levine-Tiefenbrun

Yelin

Uriel

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…An analysis of data from seven longitudinal studies found that the probability of false negatives of RT-PCR tests reached their lowest value of 20% on the third day after onset of symptoms before starting to increase again [13]. An Italian study of multiple RT-PCR tests that targeted different genes of viral RNA used a repeated testing design in the emergency room and reported sensitivity values ranging from 62% to 94% [4]. It was not clear whether they studied a test that may be considered equivalent to the Chinese test, but the range of reported sensitivity values includes the point estimate and error interval that was estimated in this study.…”

Section: Discussionmentioning

confidence: 99%

Reconstructed diagnostic sensitivity and specificity of the RT-PCR test for COVID-19

Padhye¹

2020

Preprint

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Background. Real-time reverse transcription polymerase chain reaction (RT-PCR) targeting select genes of the SARS-CoV-2 RNA has been the main diagnostic tool in the global response to the COVID-19 pandemic. However, the diagnostic accuracy of the test has not been studied systematically outside of the laboratory setting. The aim of this study is to provide estimates of the diagnostic sensitivity and specificity of the RT-PCR test developed by China CDC. Methods. The study design is a secondary analysis of published findings on 1014 patients in Wuhan, China, of whom 601 tested positive and 413 were negative for COVID-19. Sensitivity and specificity were reconstructed using a Bayesian approach from probabilistic knowledge of the diagnostic errors. Predictive values of the test were calculated, resulting in estimates for the number of confirmatory tests that are needed for establishing the presence or absence of COVID-19, depending on the prior probability of a patient having the disease. Results. The sensitivity of the RT-PCR diagnostic test was estimated to be 0.777 (95% CI: 0.715, 0.849), while the specificity was 0.988 (95% CI: 0.933, 1.000). The confidence intervals include sampling error in addition to the error due to probabilistic knowledge of the data. Discussion. The Chinese version of the RT-PCR test had a conspicuous rate of false negative results, likely missing between 15% and 29% of patients with COVID-19. For a patient with a prior probability of COVID-19 greater than 18%, at least two negative test results would be needed to lower the chances of COVID-19 below 5%. Caution is advised in generalizing these findings to other versions of the RT-PCR test that are being used in diverse geographic regions.

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“…Accurate and sensitive measurement of virus-specific antibodies could complement diagnostic testing, provide information about the true prevalence of infection, provide insight into anti-viral immunity, and help assess vaccine responses. However, a lack of required sensitivity and specificity of many of the SARS-CoV-2 antibody tests available to date have led some to conclude that they have limited clinical utility in combating COVID-19 31 . Here, we present a modified ELISA protocol with exceptional sensitivity with high concentration samples that enables the detection of low levels of antigen-specific antibodies in human specimens.…”

Section: Discussionmentioning

confidence: 99%

SARS-CoV-2 reactive antibodies in unexposed individuals revealed by a high sensitivity, low noise serologic assay

Yuen

Steiner

Pihl

et al. 2020

Preprint

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The COVID-19 pandemic has significantly impacted work, economy, and way of life. The SARS-CoV-2 virus displays unique features including widely varying symptoms and outcomes between infected individuals. Sensitive measurement of SARS-CoV-2 specific antibodies would provide new insight into virus transmission dynamics, pre-existing cross-reactive immunity, and the nuances of SARS-CoV-2 pathogenesis. To date, existing SARS-CoV-2 serology tests have limited utility due to insufficient detection of antibody levels lower than what is typically present after several days of symptoms. To measure lower quantities of SARS-CoV-2 IgM, IgG, and IgA with higher resolution than existing assays, we developed a new ELISA protocol with a distinct plate washing procedure and timed plate development via use of a standard curve. This BU ELISA method exhibits very low signal from plasma or serum samples added to uncoated wells at as low as a 1:5 dilution. Use of this method revealed circulating SARS-CoV-2 receptor binding domain (RBD) and nucleocapsid protein (NP) reactive antibodies from blood samples drawn prior to May 2019. Of our pre-pandemic cohort, no SARS-CoV-2 RBD-reactive IgG antibodies were detected in subjects over 70 years of age, and SARS-CoV-2 NP-reactive antibodies were present at similar levels to infected subjects in some individuals and very low in others. Also, samples drawn in May 2020 from two individuals with no symptoms or no known virus exposure contained SARS-CoV-2 RBD-reactive antibodies at intermediate amounts compared with other subject groups (higher than pre-pandemic and lower than confirmed SARS-CoV-2 infected). The one asymptomatic SARS-CoV-2 convalescent subject in our study possessed comparable amounts of SARS-CoV-2 NP-specific IgM and IgG but drastically lower IgA than the symptomatic counterparts. Also, our assay detected positive signal from samples that gave negative results in a commercially available Lateral Flow Device (LFD) and the EUA approved Abbott IgG chemiluminescent microparticle immunoassay for SARS-CoV-2 antibody detection. We propose that this improved ELISA protocol, which is straightforward to perform, low cost, and uses readily available commercial reagents, is a useful tool to elucidate new information about SARS-CoV-2 infection and has promising implications for improved detection of all analytes measurable by this platform.

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Sensitivity, Specificity and Predictive Values of Molecular and Serological Tests for COVID-19: A Longitudinal Study in Emergency Room

Cited by 39 publications

References 41 publications

Association of COVID-19 RT-qPCR test false-negative rate with patient age, sex and time since diagnosis

Association of COVID-19 RT-qPCR test false-negative rate with patient age, sex and time since diagnosis

Reconstructed diagnostic sensitivity and specificity of the RT-PCR test for COVID-19

SARS-CoV-2 reactive antibodies in unexposed individuals revealed by a high sensitivity, low noise serologic assay

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