This case was based on several published studies compiling hematological changes in COVID-19 patients in an attempt to find trends and discover various biomarkers for tracking the severity of the disease.
The studies compared many different cases, particularly comparing CBC data from mild to severe cases. Some of these trends, which could presumably be used as biomarkers for increasing severity and worsening prognosis, include:
1. Neutrophilia is noted in severe COVID patients but is not seen in mild to moderate cases.
2. Increasing lymphocytopenia is seen as severity increases. Lymphocytopenia seems to be a marker of severity and poor prognosis. Even more significant was a decrease in the large granular lymphocytes in the most severe cases, which appeared to be a marker for mortality.
3. Many studies suggest that an elevated neutrophil/lymphocyte ratio (NLR) is a risk factor for mortality.
4. Morphological changes are seen in many severe cases, although no specific change (as of the time of this writing) can be considered a biomarker.
5. Although this course is on white blood cells, a consistent finding in red blood cell parameters includes an increase in red blood cell distribution width (RDW) with increasing severity.
