Clinical symptoms must be assessed to aid in the diagnosis of COVID-19. Both the WHO and United States Centers for Disease Control and Prevention (CDC) have issued guidance for key clinical and epidemiological findings suggestive of COVID-19 [24,25]. Extensive laboratory tests should be requested to confirm diagnosis of COVID-19. RT-PCR should be performed in isolated samples of throat swabs, sputum, stool, and blood samples.
Key laboratory results on admission include leucocytes below or above the normal range; neutrophils above the normal range; lymphocytes, haemoglobin and platelets below the normal range. Key liver findings may include elevated alanine aminotransferase, aspartate aminotransferase, C-reactive protein, creatine kinase, lactate dehydrogenase, blood urea nitrogen, and serum creatinine levels. Regarding the infection index, procalcitonin levels may be above the normal range .
Radiological findings may also aid the diagnosis of pneumonia in virally infected patients. Bilateral and multi-lobe lung involvement were common in over 75% and 71% of adult patients, respectively [21,22]. In paediatric patients, the following criteria for rapid respiratory rate should be followed for diagnosis of COVID-19 associated pneumonia: ≥60 times/min for less than 2 months old; ≥50 times/min for 2–12 months old, ≥40 times/min for 1–5 years old, ≥30 times/min for >5 years old (after ruling out the effects of fever and crying) .
Differential diagnosis can include other viral respiratory infections caused by SARS virus, influenza virus, parainfluenza virus, adenovirus, respiratory syncytial virus and metapneumovirus . These patients present with similar clinical presentations, except for normal or decreased leukocyte count in some patients. Patients may also present with pneumonia due to bacterial causes, which may be accompanied by high fever and moist rale cough . Mycoplasmal pneumonia is another common type of false presentation. Chest X-ray images for such patients may indicate reticular shadows and small patchy or large consolidations. Mycoplasma-specific IgM are helpful for this differential diagnosis. Epidemiological exposure and blood or sputum culture will be helpful for ensuring the correct diagnosis of COVID-19