Corey Heitz1, Justin Morgenstern2, Christopher Bond3, William K Milne4. 1. From the, Lewis Gale Medical Center, Salem, VA, USA. 2. Markham Stouffville Hospital, Markham, Ontario, Canada. 3. the, University of Calgary, Calgary, Alberta, Canada. 4. and the, University of Western Ontario, Goderich, Ontario, Canada.
A novel coronavirus, SARS‐CoV‐2, or COVID‐19, emerged in China in December 2019. In early 2020, the virus spread throughout the world in pandemic fashion. Diagnosis was made difficult due to inexperience with signs and symptoms, shared features with other respiratory viruses, and delays in testing.
Early versions of polymerase chain reaction (PCR) testing had high false‐negative rates.
With an influx of patients to emergency departments (EDs) worldwide, it would be important to understand signs and symptoms, diagnostic accuracy of various testing modalities, and limitations of testing.
ARTICLE SUMMARY
This study is a scoping review of published research, with the primary objective being descriptive information regarding the diagnostic characteristics of rapid reverse transcription PCR (rRT‐PCR). In addition, possible biases of current research are discussed as well as a review of the diagnostic characteristics of history and physical findings and routine laboratory and imaging tests. In total 1,907 citations were screened, with 87 studies ultimately included, none of which met the Standards for Reporting of Diagnostic Accuracy (STARD) criteria. Fever is the most common finding, with loss of taste and smell also common. Cough and shortness of breath are common but not able to distinguish COVID‐19 from other respiratory illnesses. Lymphopenia is common but not diagnostic. rRT‐PCR is often used as the criterion standard, but has high false‐negative rates. Imaging studies are neither sensitive nor specific.
QUALITY ASSESSMENT
This was a scoping review and as such not intended to be a systematic review and meta‐analysis. Studies were limited to the English language, and while the majority of studies came from the non‐English literature published in English, there remains the possibility of studies that may not have been included. For diagnostic accuracy of various signs/symptoms and tests, the criterion standard was often rRT‐PCR, which is itself an imperfect criterion standard. None of the included standards rigorously followed criteria for standardizing research into diagnostic testing. Multiple biases exist in the published literature.
KEY RESULTS
Eighty‐seven studies were included, of 1,907 citations that were screened. The main results can be seen in Table 1.
Table 1
Key Results
Diagnostic Finding
Frequency
Sensitivity and Specificity
LR+
LR–
Clinical examination
Fever
84%–87%
5.3
0.61
Hyposmia
7.1
0.38
Hypogeusia
47‐73%
Anosmia
58%
Cough
Routine laboratory examinations
Lymphopenia
>50%
RT‐PCR
Single test
Sn 60%–78%
Two testsTwo tests
Sn 86%
Five tests
Sn 98%
Serology
IgM or IgG > 20 days
Sn 82%–100%, Sp 87%–100%
Imaging
Chest X‐ray
Sn 33%–60%
CT scan
Sn 72%–94%, Sp 24%–100%
Key ResultsSn 33%–60%
AUTHORS’ COMMENTS
Diagnosis of COVID‐19 is made difficult by overlapping signs and symptoms with numerous other respiratory illnesses as well as a lack of rigorous data regarding laboratory and viral‐specific testing.
TWITTER POLL
PAPER‐IN‐A‐PIC FROM KIRSTY CHALLEN, @KIRSTYCHALLEN
TAKE‐TO‐WORK POINTS
Diagnosis of COVID‐19 is challenging. A single rRT‐PCR test has a relatively high false‐negative rate.