Rapid identification of SARS-CoV-2-infected patients at the emergency department using routine testing

Clin Chem Lab Med. 2020 Jun 29;58(9):1587-1593. doi: 10.1515/cclm-2020-0593. Print 2020 Aug 27.


Objectives: The novel coronavirus disease 19 (COVID-19), caused by SARS-CoV-2, spreads rapidly across the world. The exponential increase in the number of cases has resulted in overcrowding of emergency departments (ED). Detection of SARS-CoV-2 is based on an RT-PCR of nasopharyngeal swab material. However, RT-PCR testing is time-consuming and many hospitals deal with a shortage of testing materials. Therefore, we aimed to develop an algorithm to rapidly evaluate an individual's risk of SARS-CoV-2 infection at the ED.

Methods: In this multicenter retrospective study, routine laboratory parameters (C-reactive protein, lactate dehydrogenase, ferritin, absolute neutrophil and lymphocyte counts), demographic data and the chest X-ray/CT result from 967 patients entering the ED with respiratory symptoms were collected. Using these parameters, an easy-to-use point-based algorithm, called the corona-score, was developed to discriminate between patients that tested positive for SARS-CoV-2 by RT-PCR and those testing negative. Computational sampling was used to optimize the corona-score. Validation of the model was performed using data from 592 patients.

Results: The corona-score model yielded an area under the receiver operating characteristic curve of 0.91 in the validation population. Patients testing negative for SARS-CoV-2 showed a median corona-score of 3 vs. 11 (scale 0-14) in patients testing positive for SARS-CoV-2 (p<0.001). Using cut-off values of 4 and 11 the model has a sensitivity and specificity of 96 and 95%, respectively.

Conclusions: The corona-score effectively predicts SARS-CoV-2 RT-PCR outcome based on routine parameters. This algorithm provides the means for medical professionals to rapidly evaluate SARS-CoV-2 infection status of patients presenting at the ED with respiratory symptoms.

Keywords: COVID-19; SARS-CoV-2; algorithm; coronavirus; emergency department; pandemic; prediction-model.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Algorithms*
  • Betacoronavirus*
  • C-Reactive Protein / analysis
  • COVID-19
  • COVID-19 Testing
  • Clinical Laboratory Techniques
  • Coronavirus Infections / blood
  • Coronavirus Infections / diagnosis*
  • Diagnostic Tests, Routine / methods*
  • Emergency Service, Hospital
  • Female
  • Ferritins / blood
  • Humans
  • L-Lactate Dehydrogenase / blood
  • Lymphocyte Count
  • Male
  • Middle Aged
  • Neutrophils / metabolism
  • Pandemics
  • Pneumonia, Viral / blood
  • Pneumonia, Viral / diagnosis*
  • Retrospective Studies
  • Reverse Transcriptase Polymerase Chain Reaction
  • SARS-CoV-2


  • C-Reactive Protein
  • Ferritins
  • L-Lactate Dehydrogenase