Objectives To compare the performance of chest computed tomography (CT) scan versus reverse transcription polymerase chain reaction (RT-PCR) as the reference standard in the initial diagnostic assessment of coronavirus disease 2019 (COVID-19) patients. Design A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A search of electronic information was conducted using the following databases: MEDLINE, EMBASE, EMCARE, CINAHL and the Cochrane Central Register of Controlled Trials. Setting Studies that compared the diagnostic performance within the same patient cohort of chest CT scan versus RT-PCR in COVID-19 suspected patients. Participants Thirteen non-randomised studies enrolling 4092 patients were identified. Main outcome measures Sensitivity, specificity and accuracy were primary outcome measures. Secondary outcomes included other test performance characteristics and discrepant findings between both investigations. Results Chest CT had a median sensitivity, specificity and accuracy of 0.91 (range 0.82–0.98), 0.775 (0.25–1.00) and 0.87 (0.68–0.99), respectively, with RT-PCR as the reference. Importantly, early small, China-based studies tended to favour chest CT versus later larger, non-China studies. Conclusions A relatively high false positive rate can be expected with chest CT. It is possible it may still be useful to provide circumstantial evidence, however, in some patients with a suspicious clinical presentation of COVID-19 and negative initial Severe Acute Respiratory Syndrome Coronavirus 2 RT-PCR tests, but more evidence is required in this context. In acute cardiorespiratory presentations, negative CT scan and RT-PCR tests is likely to be reassuring.

The objective of this study was to quantitatively compare outcomes between standard excision (SE) and Mohs micrographic surgery (MMS) for basal cell carcinoma (BCC). A systematic review and metaanalysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines and a search of electronic databases was conducted to identify all randomised controlled trials (RCTs) and observational studies comparing the outcomes of SE versus MMS for BCC. The primary outcome was the recurrence rate for primary and recurrent BCC. The secondary outcomes included the cost of treatment, aesthetic results, the rate of incomplete excision, and the surgical defect size post excision. Five studies enrolling 2060 lesions were identified. There was a statistically significant difference between MMS and SE groups in terms of recurrence rate for primary BCCs (odds ratio (OR) = 0.44, confidence interval (CI) = 0.16 to 0.97, P = 0.04) and recurrent BCCs (OR = 0.33, CI = 0.12 to 0.97, P = 0.04). For secondary outcomes, MMS had improved results compared with SE, except for mean cost. In conclusion, both primary and secondary BCCs treated with MMS have a reduced recurrence rate and defect size thus simplifying reconstruction. However, due to higher costs and operative time attributed to MMS, it should be reserved for high-risk BCCs.

Purpose To compare the performance of chest computed tomography (CT) scan versus reverse transcription polymerase chain reaction (RT-PCR) in the initial diagnostic assessment of coronavirus disease 2019 (COVID-19) patients. Methods A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A search of electronic information was conducted to identify all relevant studies comparing the diagnostic performance of chest CT scan versus RT-PCR in COVID-19 suspected cases. Sensitivity, specificity and accuracy were primary outcome measures. Secondary outcome measures included other test performance characteristics, discrepant findings between both investigations and main chest CT findings. Random effects modelling was used for the analyses. Results Eight non-randomised retrospective studies enrolling 1910 patients were identified. Chest CT was more sensitive but less specific than RT-PCR. Accuracy was not statistically significantly different between chest CT and RT-PCR for the identification and exclusion of COVID-19 cases (Odds Ratio [OR] = 0.40, P = 0.15) in the context of hospitalised patients in a pandemic. Chest CT was shown to detect patients with false-negative RT-PCR results and true positives. Ground-glass opacities and consolidations were the most common chest CT manifestations. Conclusions Chest CT is not superior to RT-PCR for the initial detection of COVID-19 and has more false positives. It is likely to be useful in confirming COVID-19 in patients with a suspicious clinical presentation, but who have a false-negative SARS-CoV-2 RT-PCR test.

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