Investigating a Covid-19 infection
Around 500 days back when the novel corona virus stuck the world population in the earlier part of 2020, it led to overwhelming burden on the global healthcare infrastructure as well as casualties due to the contagious nature of the infection. What further belittled the whole world in front of this Invisible enemy was lack of knowledge of how this virus behaves in our body and what are the changes caused by it to the physio-biochemical machinery of our body. It would not be therefore wrong to think that it was a war against the whole mankind waged by one invisible enemy- the novel Corona virus. Over the period of one and half year much have been understood now about how the patho-physiology of covid-19 infection which has improved patient management. Much of the indicators of pathological damage caused by the virus can be assessed through blood investigations alone. This helps to timely identify the risk profile for severe disease in an affected individual so that treatment can be scaled up to improve the patient outcome. Importance of some of these blood investigations is discussed below.
1. Complete blood counts test gives us information of levels of different types of cells present in out blood. In covid patients it is observed that platelets counts is reduced in the blood Very low lymphocyte count was found in the patients that eventually require ICU management.
2. HbA1C: This test tell us about long term control of blood glucose in diabetic patients. Poor control of blood glucose in diabetic patient increases risk of moderate to severe disease.
3. C-Reactive protein: CRP is a protein that is synthesized by liver, as a part of a group of protein known as acute phase reactant. It a part of body's immune response to eliminate the invading pathogen. Level of CRP and time taken by it to double is used to evaluate if there is an imminent cytokine storm, a stage where body own immune system gets hyperstimulated to cause harm to ones own body itself.
4. IL-6 It is also a pro-inflammatory protein of cytokine family. IL-6 levels are also use to monitor the extent of inflammation that is occurring in the body due to immune response it is also used to evaluate if there is an imminent cytokine storm, in which case IL-6 receptor antagonists agents like Tocilizumab have proved to be life saving in many cases.
5. D-dimer: This protein is formed in the blood by degradation of fibrin which is protein involved in normal coagulation process in the blood Covid is known to be a procoagulation state in which coagulation is increased due to underlying inflammation. There is formation of clots which gets lodged in lungs causing hypoxia, and if the clot goes to heart or brain it may lead to heart attack or stroke respectively. D-dimer monitoring helps to know the need of anti coagulant administration the patients and thus prevent them from developing severe disease
6. Liver function tests: This tests includes Serum bilirubin levels, liver enzymes like AST/ALT,levels of serum protein like albumin, globulin, As covid infections becomes severe, raised liver enzymes. Low Albumin level is also seen in covid infection.
7. Kidney function tests. This test mainly includes assessment of urea and creatinine levels. Derangement of kidney function test is indicator of severe disease causing multi organ failure.
8. Apart from these monitoring cardiac proteins like troponin helps to know the risk of cardiac event due to viral myocarditis
- By Dr Dinesh Puri
PhD MD (Biochemistry)
Professor & HOD Biochemistry GTB Hospitals and medical college, New Delhi