COVID: Clinical chemistry tests may help in early stage patient monitoring

The recent studies of the novel coronavirus disease (COVID-19) indicate that most patients tested show elevated levels of C-reactive protein (CRP). In addition to CRP, many patients tested have elevated levels of several other parameters. Among those were alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), ferritin and creatine kinase (CK). Moreover, a d-dimer concentration greater than 1 µg/mL, among other risk factors, could help clinicians to identify patients with poor prognosis at an early stage.

Determining one of the most sensitive acute phase proteins. IFCC recommends testing CRP levels from COVID-19 patients among several other common in vitro diagnostics parameters – IFCC Information Guide on COVID-19.

Elevated levels of CRP may indicate severe viral infection. C-reactive protein (CRP) is a normal constituent of serum present in healthy individuals in very low concentrations. Invasive bacterial infection and extensive tissue damage cause increased CRP levels. Levels in plasma usually rise dramatically after, e.g., myocardial infarction, trauma, infection, inflammation or surgery. The increase begins within 6 to 12 hours, and level may reach 2000 times normal. Determination of CRP is clinically useful for screening for organic disease, assessment of the activity of inflammatory disease, detection of intercurrent infections or after surgery. According to IFCC, elevated levels of CRP may indicate severe viral infection, viremia, or viral sepsis in COVID-19 diagnosed adult patients.

Monitoring iron therapy and indicating liver damage. IFCC recommends testing Ferritin levels from COVID-19 patients among several other common in vitro diagnostics parameters (IFCC Information Guide on COVID-19).

Ferritin is an iron storage protein. The determination of ferritin is important in iron metabolism diagnosis, monitoring iron therapy, ascertaining the iron reserves in groups at risk and in differential diagnosis of anemias. According to IFCC, elevated levels of ferritin may indicate severe inflammation in COVID-19 diagnosed adult patients. While very low serum ferritin values are always indicative of iron deficiency, very high serum ferritin values have many implications. Increased serum ferritin can be suggestive of iron overload but is also seen in conjunction with liver parenchymal damage, infections, inflammation and malignant diseases without any quantitative relationship to the iron reserve.

An aid for the diagnosis of venous thromboembolism and coagulation. IFCC recommends testing D-dimer levels from COVID-19 patients among several other common in vitro diagnostics parameters (IFCC Information Guide on COVID-19). D-Dimer is a small protein fragment, present in the blood after a blood clot is degraded in fibrinolysis by plasmin. Many clinical conditions are associated with increased blood concentrations of D-dimer. According to IFCC, elevated levels of D-dimer may indicate activation of coagulation and/or disseminated coagulopathy in COVID-19 diagnosed adult patients. Increased concentrations of D-dimer may include venous thromboembolism (VTE), arterial thrombosis (including myocardial infarction and stroke), disseminated intravascular coagulation (DIC) association with recurrent thrombotic risk following anticoagulation, post-operative state, significant liver disease, malignancy and normal pregnancy. D-Dimer testing has become a useful laboratory tool for the diagnosis of VTE because it has high negative predictive value when used in combination with pretest clinical probability.

Choosing right clinical chemistry analyzer in the time of pandemic. Across the globe general safety and occupational safety of healthcare workers has become the priority. Authorities are taking all possible measures to reduce the community spread. Hospitals and COVID centers are focusing on waste minimization and proper waste disposal. From the biochemistry laboratory perspective, liquid waste generation, and waste disposal is a huge concern in the COVID times. Hence it is highly recommended to place analyzers with disposable cuvettes so that there is zero carry over of samples and one must look for an analyzer where there are no external tubing or cans for waste disposal. Also, the water consumption should be least, as more water being used, more waste would be generated. WHO is preferring such analyzers for their COVID centers.