Diagnostic accuracy of screening tests for patients suspected of COVID-19, a retrospective cohort study

Abstract

Background

The diagnostic gold standard for Coronavirus-2019 disease (CoViD-19) is reverse transcriptase-polymerase chain reaction (RT-PCR). However, its sensitivity might be suboptimal. The current study aims to investigate predictive factors for false-negative nasopharyngeal RT-PCR in CoViD-19 patients. Additionally, the specificity and sensitivity of RT-PCR on the nasopharyngeal swab, serology and chest computerized-tomography (CCT) as a screening tool for the diagnosis of CoViD-19 were investigated.

Methods

Medical records of patients admitted at the university hospital UZ Brussel during the CoViD-19 epidemic were reviewed. A group of CoViD-19 patients with false-negative RT-PCR was identified through scrupulous examination of medical records. Serological testing was performed through chemiluminescent microparticle assay.

Results

Eighteen CoViD-19 patients with ‘false negative’ RT-PCR were identified and compared to 51 ‘true positives’. Logistic regression for prediction of ‘false negative’ RT-PCR found significantly higher serology results at hospitalization and more intensive care unit admission in the group with false-negative testing. In a cohort of 228 patients, the sensitivity of RT-PCR for the diagnosis of CoViD-19 was 85%. The sensitivity of serology was 86% and its specificity 92%. Chest computerized-tomography (CCT) showed a sensitivity of 93%, its specificity was 62%. By combining RT-PCR and serology results any ‘false negative’ could be excluded.

Conclusions

In this cohort, the sensitivity and specificity of RT-PCR and serology for the diagnosis of CoViD-19 were high and comparable. CCT had the highest sensitivity and confirmed its efficacy as a screening tool. CoViD-19 patients, who have a more severe presentation, might have negative RT-PCR and positive serology results.

Keywords:

• Severe acute respiratory syndrome coronavirus 2
• Coronavirus disease 2019
• reverse transcriptase-polymerase chain reaction
• chemiluminescent microparticle assay
• serological testing

Authors’ contributions

MM: concept, study design, data collection, data analysis and interpretation, writing and revision. JVL: study design, writing and revision. BI and DDG: data collection, writing and revision. WC: data analysis and interpretation, writing and revision. SDA and DP: concept, writing and revision.

Ethical approval and consent to participate

The study was conducted following the study protocol, the Declaration of Helsinki and applicable regulatory requirements. The Ethics Committee of the University Hospital Brussels, named ‘Commissie Medische Ethiek, Vrij Universiteit Brussel’, approved the protocol (Ethics Committee approval number: B1432020000090). Given the retrospective nature of the study, which did not demand any deviation from standard clinical care, and the fact that all data were anonymized, a waiver of informed consent was obtained from the same ethics committee.

Consent for publication

Because of the retrospective nature of the study, which did not demand a deviation from standard clinical care, and the fact that all data was anonymized, informed consent from the patient or the next of kin was not essential.

Acknowledgments

We would like to thank the study coordinating team of the UZ Brussel for their support. Furthermore, we would like to underline the essential support of the University of Brussel, VUB, which gave us the possibility to finance the current study.

Disclosure statement

No potential conflict of interest was reported by the authors. The authors declare to have applied for funding to ‘VUB COVID-19 CALL’.

Additional information

Funding

This research was financed by the Vrij Universiteit Brussel (VUB).