Initial investigations

Initial investigations
Order the following investigations in all patients with severe illness:
• Pulse oximetry
• ABG (as indicated to detect hypercarbia or acidosis)
• Comprehensive metabolic panel
• Coagulation screen
• Inflammatory markers (serum procalcitonin and C-reactive protein)
• Serum troponin
• Serum lactate dehydrogenase
• Serum creatine kinase.
The most common laboratory abnormalities in patients hospitalised with pneumonia include leukopenia,
lymphopenia, leukocytosis, and elevated liver transaminases. Other abnormalities include neutrophilia,
thrombocytopenia, decreased haemoglobin, decreased albumin, and renal impairment.[4] [5] [6]
Pulse oximetry may reveal low oxygen saturation (SpO₂ <90%).
Blood and sputum cultures
Collect blood and sputum specimens for culture in all patients to rule out other causes of lower respiratory
tract infection, especially patients with an atypical epidemiological history.
Specimens should be collected prior to starting empirical antimicrobials if possible.
Molecular testing
Molecular testing is required to confirm the diagnosis. Diagnostic tests should be performed according to
guidance issued by local health authorities.
Perform real-time reverse-transcription polymerase chain reaction (RT-PCR) assays for severe acute
respiratory syndrome coronavirus 2 (SARS-CoV-2) in all patients with suspected infection:[54]
• Collect lower respiratory tract specimens (sputum, endotracheal aspirate, bronchoalveolar lavage)
where possible and depending upon the patient’s condition
• Upper respiratory tract specimens (nasopharyngeal aspirate or combined nasopharyngeal and
oropharyngeal swabs) may be used if lower respiratory tract specimens cannot be collected
• If initial testing is negative in a patient who is strongly suspected to have COVID-19, recollect
specimens from multiple respiratory tract sites (nose, sputum, endotracheal aspirate) and retest
• Blood, urine, and stool specimens may also be used to monitor for the presence of the virus;
however, sensitivity of diagnoses at these sites is uncertain.
Also rule out infection with other respiratory pathogens (e.g., influenza, atypical pathogens). Collect
nasopharyngeal swabs for testing.
Serological testing is not available as yet, but assays are in development.[55]
All imaging procedures should be performed according to local infection prevention and control
procedures to prevent transmission.
Chest x-ray
• Order a chest x-ray in all patients with suspected pneumonia. Unilateral lung infiltrates are found in
25% of patients, and bilateral lung infiltrates are found in 75% of patients.[4] [5] [56]
Computed tomography (CT) chest
• Consider ordering a CT scan of the chest. It is particularly helpful in patients with suspected
pneumonia who have a normal chest x-ray in order to detect infiltrates with greater sensitivity.[56]
[57] [58] [59] Evidence of viral pneumonia on CT may precede a positive RT-PCR result for SARSCoV-2 in some patients.[60] CT is the primary imaging modality in China.[61]
• Nearly all patients in the initial cohort of 41 patients had bilateral multiple lobular and subsegmental
areas of consolidation.[4] However, multiple mottling and ground glass opacity was only identified
in 14% of patients in another study.[5] Small nodular ground glass opacities are the most common
finding in children