Quick points on how do we diagnose COVID-19 by blood tests?
1) CRP (C-reactive protein): It's a marker of inflammation and sepsis gets elevated in COVID. Normal levels are up to 5, above 5 it is positive, more then 10 it indicates a severe infection.
2) IL -6 (Interleukin 6): It's a marker of severe sepsis. There is a cytokine storm in severe COVID and elevated levels. Normal levels 5-15 pg/ml
3) CBC (Complete Blood Count test) shows very low WBC counts below 4000 or very high above 10,000. Neutrophil to lymphocyte ratio more then 3.5 indicates COVID-19 positive.
4) D- dimer levels elevated in covid if it's severe where the coagulation process of blood gets accelerated and pt requires anticoagulation. A normal level is usually less than 0.5
5) PCT (Procalcitonin Test) levels: a marker of severe infection elevated in covid infection.
6) Serum Ferritin: levels elevated as they neutralize toxic substances from viruses or bacteria.