COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

Diagnosis Xu B, Xing Y, Peng J, et al. Chest CT for detecting COVID-19: a systematic review and meta-analysis of diagnostic accuracy. Eur Radiol. 2020 Oct;30(10):5720-5727. doi: 10.1007/s00330-020-06934-2. Epub 2020 May 15.

OBJECTIVE: The purpose of this article was to perform a systematic review and meta-analysis regarding the diagnostic test accuracy of chest CT for detecting coronavirus disease 2019 (COVID-19).

METHODS: PubMed, Embase, Web of Science, and CNKI were searched up to March 12, 2020. We included studies providing information regarding diagnostic test accuracy of chest CT for COVID-19 detection. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Sensitivity and specificity were pooled.

RESULTS: Sixteen studies (n = 3186 patients) were included. The risks of bias in all studies were moderate in general. Pooled sensitivity was 92% (95% CI = 86-96%), and two studies reported specificity (25% [95% CI = 22-30%] and 33% [95% CI = 23-44%], respectively). There was substantial heterogeneity according to Cochran's Q test (p < 0.01) and Higgins I2 heterogeneity index (96% for sensitivity). After dividing the studies into two groups based on the study site, we found that the sensitivity of chest CT was great in Wuhan (the most affected city by the epidemic) and the sensitivity values were very close to each other (97%, 96%, and 99%, respectively). In the regions other than Wuhan, the sensitivity varied from 61 to 98%.

CONCLUSION: Chest CT offers the great sensitivity for detecting COVID-19, especially in a region with severe epidemic situation. However, the specificity is low. In the context of emergency disease control, chest CT provides a fast, convenient, and effective method to early recognize suspicious cases and might contribute to confine epidemic.

KEY POINTS: • Chest CT has a high sensitivity for detecting COVID-19, especially in a region with severe epidemic, which is helpful to early recognize suspicious cases and might contribute to confine epidemic.

Discipline / Specialty Area Score
Hospital Doctor/Hospitalists
Internal Medicine
Family Medicine (FM)/General Practice (GP)
General Internal Medicine-Primary Care(US)
Public Health
Infectious Disease
Intensivist/Critical Care
Comments from MORE raters

Infectious Disease rater

Chest CTs were found to have a low specificity (25-30%) and a high sensitivity (>90%) for diagnosing COVID-19 in this meta-analysis. This modality may have a role in assessing disease severity and prognosis, but unlikely to be useful as a primary diagnostic test given the availability of PCR-based assays for COVID antigens.

Infectious Disease rater

This is a composite analysis of the ability of CT to be the first point of diagnosis of SARS-CoV-2 infection. CT's ability in this setting comports with clinical impression, but the paper does little to add to existing knowledge. In many of the reviewed papers, the radiologist was not blinded to the virology. All but one of the papers reviewed were from China. Other geographic regions may have different results. Nonetheless, this is a valuable paper emphasizing the difficulty in diagnosing COVID-19 disease.

Intensivist/Critical Care rater

Chest CT may be sensitive. However, as expected, specificity is low. It also requires expertise and resources. In my opinion, it should not be used as a routine or screening test for diagnosis.

Internal Medicine rater

Data on specificity is lower than expected. We need to be cautious when diagnosing patients with negative RT-PCR.

Public Health rater

It is interesting to note that CT scans of the chest in COVID-19 patients tend to have a high sensitivity but low specificity. One might expect that result, since we are dealing with a viral pneumonia. I suspect the same result is true for chest radiographs, but it would also be interesting to validate my suspicion with some real-world observations.