How Is COVID-19 Diagnosed? Can It Be Screened?
Diagnosis & Screening of Coronavirus
The emergence of the mysterious virus called 2019 Novel Coronavirus has sent the world population into a panic state. As a result, hospitals and clinics are crowded with patients especially those with respiratory symptoms. So, everyone must have been wondering, how do the doctors diagnose this disease? It is considerably new. How can we develop the test so quickly?
Most of the time, even for a disease that has the most advanced and specific test, a lot of them can be pre-diagnosed with clinical pictures. Doctors will assess the patients based on history, clinical symptoms and signs on examination. If the patient is found to be at risk based on history and shows suspected symptoms and signs, then they will be sent for further investigation to confirm the diagnosis.
In the case of the Wuhan Virus or Novel Coronavirus 2019 (COVID-19), an important background history includes travel history to China, sick contact and also food consumption, especially exotic food such as wild animals or raw meat, seafood and poultry. Symptoms are mostly non-specific, which are mainly fever and respiratory symptoms. However, patients can also have other symptoms such as headache, diarrhoea, and vomiting. Clinical signs that doctors usually look out for are physical signs such as patient’s breathing patterns, the colour of their lips and any lethargic appearance. The patient’s vital signs such as temperature, oxygen saturation, pulse, and breathing rate are also important. Doctors will listen to the lungs to check for any possible signs of pneumonia.
If a symptomatic patient is suspected of this infection, few samples are needed to be sent to the laboratory. The samples are required for 2 main tests as follow:
Reverse Transcriptase - Polymerase Chain Reaction Test (RT-PCR)
2 samples are needed for this test which are from the lower respiratory tract of our lungs and the other is from the upper respiratory tract. The first sample can be obtained if the patient is able to cough out sputum. Otherwise, a more invasive technique may be needed such as aspiration or alveolar lavage. The second sample from the upper respiratory tract can be obtained by the swab test. This is usually obtained by a swab sample from the nasopharyngeal and oropharyngeal area.
Serology test which requires blood sampling will be obtained on day 5-8 after a patient presented with symptoms or upon discharge from hospital.
Other routine tests
Another routine test such as infective and inflammatory markers may also be done such as full blood count, C-Reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR).
According to the Ministry of Health protocol, all patients that visit any healthcare facilities should be screened for COVID-19 at triage. Currently, there is no rapid test available to screen for this virus. At the triage counter, a risk assessment will be conducted. The criteria for a patient to be suspected of COVID 2019 are:
A person with fever AND clinical sign/symptoms suggestive of pneumonia OR severe respiratory infection with breathlessness AND had history of travel to or reside in Mainland China within the last 14 days; OR close contact with a confirmed case of COVID-19.
Source: KKM COVID-19 protocol
Screening at travel borders & airports
As we all know, this infection originates from China and is spread from human to human as they travel from China to another country. Therefore, screening is conducted at the airport and at the border to prevent further spread. Travellers and flight crews arriving from China are screened for fever. Those without fever will be sent home with a health alert card while the suspected person will be sent to a health screening area for further assessment.
Written by: Dr Nur Syuhada binti Zulkifli
MD, Universiti Kebangsaan Malaysia (UKM)1 Feb 2020