key: cord-0766791-n18k9584
authors: Lang, Guanjing; Su, Junwei; Wu, Wenrui; Zhao, Hong; Ying, Shihong; Lou, Haiyan; Shen, Xiaomin; Yin, Michael T; Xu, Kaijin; Liu, Jun; Ren, Cheng; Sheng, Jifang
title: The Clinical and Radiological Manifestations in Coronavirus Disease (COVID-19) with Negative Nucleic Acid Results
date: 2020-06-25
journal: Open Forum Infect Dis
DOI: 10.1093/ofid/ofaa252
sha: 4a288a498709b5f251eabba22c46d850b3d89556
doc_id: 766791
cord_uid: n18k9584

BACKGROUND: COVID-19 was a new emerging disease with high infectiousness. Its diagnosis primarily depended on real time-polymerase chain reaction (RT-PCR) results. This study investigated epidemiological, clinical and radiological characteristics of COVID-19 with negative RT-PCR results before confirmation. METHODS: COVID-19 patients were enrolled and divided into two groups, negative group with negative RT-PCR results before confirmation and positive group with positive results at the first detection. Epidemiological and clinical features were compared. Dynamic chest CT images of negative group were evaluated. RESULT: Nighty-nine laboratory-confirmed COVID-19 including eight patients (8%) with negative RT-PCR results were included. Patients from negative group had similar epidemiological features as the average age (50.25±13.27 y in the negative group and 53.70±16.64 y in the positive group) and gender distribution (males made up 50% of the negative group and 62.6% of the positive group) were comparable. No significant difference of clinical symptoms were observed between the two groups. It was found that fever was the most common symptom for both groups, followed by cough, expectoration, chest distress, fatigue and gastroenterological symptoms. Moreover, ground-glass opacities and consolidations were main manifestations in chest CT of COVID-19 patients with or without confirmed RT-PCR results. CONCLUSIONS: Regardless of initial RT-PCR results, COVID-19 patients had similar epidemiological, clinical and chest CT features. Our study suggested values of early chest CT scan in COVID-19 screening and dynamic significance of radiology in disease monitoring to guide clinical decision.

The health crisis presented by COVID-19 had led to significant loss of life, a great burden on medical care and severe economic consequences. This emerging 2019 novel coronavirus (SARS-CoV-2) was one of seven coronavirus capable causing human infection, whose complete genome showed more than 85% identity to bat severe acute respiratory syndrome (SARS)-like CoV [1] . As a new emerging infectious diesease, [1, 3, 4] , revealing that fever were common in these patients and about 66% patients had specific exposure history. Nevertheless, a previous research focusing on differentiated clinical features between MERS and other community-acquired pneumonia (CAP) reported no significant difference was found [5] . Since high-occurrence seasons for influenza in this period, atypical clinical features and laboratory tests would confuse clinicians in screening COVID-19 from CAP and in early clinical decision.

Radiological manifestations of COVID-19 were regarded to be specific as characters of sub pleural ground-glass opacities and consolidations [6] . However, solid evidence of radiological manifestations taking place of RT-PCR result in diagnosing COVID-19 was still lacking. Since SARS-CoV-2 was highly transmissible and A c c e p t e d M a n u s c r i p t resources for care and quarantine of infected patients were limited, doctors were under tremendous pressure to exclude sputum-negative patients with highly suspected symptoms and radiological images from COVID-19 patients. Here, we retrospectively studied eight COVID-19 cases whose early nucleic acid detections were inconsistent with simultaneous radiological findings. We compared them with other defined patients whose RT-PCR results were positive at the first viral detection and explored the value of dynamic chest CT evaluation as supplementary diagnostic method for COVID-19.

When the local health authorities in Wuhan where the COVID-19 outbreak initiated declared an epidemiological alert on Jan 7th, our center, in Zhejiang province, was ordered to prepare for COVID-19 patients. On January 19th 2020, our center admitted the first case of COVID-19 in Hangzhou city. Since we had limited understanding of this new infectious disease, we followed guidelines provided by the National Health Commission of the People's Republic of China (from version 1 to 6)

[2]. Some patients had multiple negative RT-PCR results but typical clinical features and chest CT manifestations, and would have a positive RT-PCR after continued testing.

We retrospectively included all COVID-19 patients hospitalized at The First Affiliated Hospital of Zhejiang University from January 19th 2020 to February 15th 2020, and divided them into two groups: (1) the negative group with first negative RT-PCR results before subsequent confirmation and (2) the positive group with positive result at the A c c e p t e d M a n u s c r i p t first detection. Detection of COVID-19 in swabs or sputa was performed using RT-PCR (Shanghai BioGerm Medical Biotechnology Co. Ltd). As a retrospective study, we collected basic demographic features, epidemiological characteristics, clinical manifestations and chest CT images from electronic medical records. Two researchers reviewed the data collection independently to double-check the accuracy of all data.

Epidemiological and symptomatic data would be confirmed through communication with patients if the data was not clear. Approval was obtained from ethics committee.

All chest CT images were reviewed independently by two experienced radiologists in our hospital, and discrepancies were resolved by consensus. All images were viewed on both lung (width, 1500 HU; level, −700 HU) and mediastinal (width, 350 HU; level, 40 HU) settings. Chest CT images were evaluated for presence of ground-glass opacities (GGO), consolidation, mixed GGO and consolidation, centrilobular nodules, septal thickening, perilobular opacities, reticulation, architectural distortion, sub pleural bands, traction bronchiectasis and bronchial wall thickening [7] . Each lung was divided into three zones: upper (above the carina), middle (below the carina up to the inferior pulmonary vein), and lower (below the inferior pulmonary vein) zones [8] . A semiquantitative score (0-4) was assigned for each lung zone: 0, No involvement; 1, less than 25% involvement; 2, 25% to less than 50% involvement; 3, 50% to less than 75% involvement; and 4, 75% or greater involvement.

A c c e p t e d M a n u s c r i p t Continuous variables were expressed as mean with standard deviation (SD) and analyzed by t-test. CT scores of the first and second examination were analyzed by paired t-test. Categorical variables were described as numbers with percentages and were compared by Chi-square (χ²) test with Fisher's exact test. A two-sided α of less than 0.05 was considered statistically significant. Statistical analyses were performed with the SPSS software, version 22.0.

We included 99 laboratory-confirmed COVID-19 patients in the First Affiliated GGO and multifocal lobular consolidations were found in patient 1 (Fig.1A2) , patient 2 ( Fig.1B2 ) and patient 7 (Fig.2C2) , which deteriorated from previous unilateral or bilateral focal ground-glass opacities and focal sub pleural lobular consolidation. In patient 3 (Fig.1C2 ), patient 4 ( Fig.1D2 ) and patient 5 (Fig.2A2) , size of GGO increased apparently compared with those in first chest CT. In patient 6, density of GGO in lower lobe of left lung (Fig.1B1 ) attenuated in the repeated chest CT but new GGO arose below the former one (Fig.2B2 ). Chest CT of patient 8 (Fig.2D1) showed reticular opacities and interlobular septal thickening in right lung and involved region enlarged in follow-up CT scan (Fig.2D2) , meanwhile, multifocal GGO were also showed in these patients. In this study, we found no significant difference in age, sex and clinical symptoms between initial negative and positive groups, indicating that clinical features cannot be utilized to predict RT-PCR results. Consistent with previous researches (ref), the most common symptom in our patients was fever followed by respiratory symptoms and systemic discomfort, while gastroenterological symptoms occurred in few patients. The proportion of patients with expectoration was also low, between 37.5% to 50.5% in two groups, which was reported as 28% in other literature. In our center, sputum and pharyngeal swabs were the most frequently collected specimens for virological detection for convenience. However, low sensitivity of RT-PCR test was reported with a sensitivity of 58% in SARS-CoV detection [9] . Peiris et al noted a positive rate of 32% in nasopharyngeal aspirates from 75 SARS patients at initial presentation, which M a n u s c r i p t doubled to 68% after 14 days [10] . The optimal way to collect specimens and timing of collections for COVID diagnosis remains uncertain.

The underlying target of SARS-CoV-2 might be located in lower respiratory tract rather than upper site since few case developed significant upper respiratory symptoms [11] . Therefore, throat swab may not have an adequate quantity of virus to reach detection limits during incubation stage. Expectorated sputum was also difficult to obtain in patients who mainly presented dry cough or in recovering stage. These factors could partially explain low positive detection rate in sputa and swabs. However, lower respiratory tract sampling with bronchoscopy and bronchoalveolar lavage was not widely available in resource limited settings, and was also associated with increased risk of transmission [12] . However, it might be inappropriate to completely exclude COVID-19 diagnosis only based on negative RT-PCR results.

Our results suggested more emphasis should be laid on the value of serial chest CT in early diagnosis and evaluation of disease progression. As shown in our results, COVID-19 primarily present non-specific manifestations like acute fever and respiratory illness. The laboratory results indicated non-specific changes of viral infections including leukopenia or lymphopenia. Recent study summarized typical features of chest CT images of COVID-19 including multiple bilateral ground-glass opacity (GGO) and consolidation [6] , which was consistent with our findings. It was reported timely initiation of antiviral therapy in therapeutic window of SARS could inhibit viral replication, minimize subsequent immune hyperactivity, and thus improve clinical outcome [13] . Recent study revealed early diagnosis was of paramount importance to prevent disease progression of COVID-19 [14] , while data about benefits from early treatment for COVID-19 was rare.

There were some limitations in this research. This was a single-center study with a small number of cases. Though we did repeated sampling during observation, only one specimen from a single location was detected. At each sampling, multiple specimens from different sites (like oropharynx, nasopharynx, sputum, feces) should be collected and tested altogether to increase positive rates. Quantitative RT-PCR for viral load was lack in this study. Some patients in this work were still under treatment in our hospital, M a n u s c r i p t M a n u s c r i p t A c c e p t e d M a n u s c r i p t 

Beijing: China National Health Commission. Diagnosis and treatment of pneumonitis caused by new coronavirus (Trial version 6)

Genomic characterization of the 2019 novel humanpathogenic coronavirus isolated from a patient with atypical pneumonia after visiting Wuhan

Epidemiologic and Clinical Characteristics of Novel Coronavirus Infections Involving 13 Patients Outside Wuhan, China

Middle East respiratory syndrome coronavirus: a case-control study of hospitalized patients

CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)

Middle East respiratory syndrome coronavirus (MERS-CoV) infection: chest CT findings

Severe acute respiratory syndrome: temporal lung changes at thin-section CT in 30 patients

Severe acute respiratory syndrome: clinical outcome and prognostic correlates

Clinical progression and viral load in a community outbreak of coronavirus-associated SARS pneumonia: a prospective study

Clinical features of patients infected with 2019 novel coronavirus in Wuhan

Preparing intensive care for the next pandemic influenza

Role of lopinavir/ritonavir in the treatment of SARS: initial virological and clinical findings

Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series

We appreciate all clinical providers, nurses and scientific researchers for their efforts in fighting COVID-19.

None.

A c c e p t e d M a n u s c r i p t