Should laboratory markers be used for early prediction of severe and possibly fatal COVID-19?
Several laboratory tests are found to be associated with disease severity and mortality in COVID-19, and may be used to prognosticate patients and guide management.
• Around 20% of COVID-19 patients develop severe illness that may require intensive care and lead to fatal complications. This necessitates prioritization of patients requiring urgent medical care before disease progression.
• Certain laboratory markers (biomarkers) may reflect the processes involved in the clinical deterioration of infected patients. Hence, their use in the identification of patients at high risk of progression to severe disease or death has been investigated.
• Current available evidence shows that the following laboratory abnormalities in a person with COVID-19, especially when found early during hospitalization, are associated with severe or critical disease or mortality:
1. Markers of organ dysfunction
a. Reduced oxygen saturation
b. Elevated lactic dehydrogenase (LDH)
c. Elevated blood urea nitrogen (BUN) or serum creatinine
d. Elevated cardiac troponin (cTnI)
e. Elevated direct bilirubin, reduced albumin
f. High radiographic score or CT severity score, or consolidation on CT scan
2. Marker of abnormal coagulation – D-dimer
3. Markers of immune dysfunction
a. Elevated IL-6
b. Elevated C-reactive protein (CRP)
c. Elevated neutrophils
d. Reduced lymphocyte percentage
e. Reduced CD4+ T lymphocytes
4. Secondary bacterial infection – Elevated procalcitonin
• Proposed prediction models utilizing these markers, however, need further validation before they can be recommended for routine clinical use.