key: cord-0953637-66vhzqv8
authors: Kavsak, Peter A.; de Wit, Kerstin; Worster, Andrew
title: Emerging key laboratory tests for patients with COVID-19
date: 2020-04-30
journal: Clin Biochem
DOI: 10.1016/j.clinbiochem.2020.04.009
sha: 612b7c578161cd02f7031524bb65ae0e327d2a01
doc_id: 953637
cord_uid: 66vhzqv8

nan

Listed below are six key laboratory tests/areas that have an important role in monitoring patients with COVID-19 with specific tests/scores highlighted in Table 1 . Additional resources for laboratory related testing may be found at the International Federation of Clinical Chemistry and Laboratory Medicine website (IFCC Information Guide on COVID-19: https://www.ifcc.org/ifcc-news/2020-03-26-ifcc-information-guide-oncovid-19/).

The three CBC findings of poor prognosis are: leukocytosis, thrombocytopenia, and lymphocytopenia. 1-3 Lymphocytopenia occurs across populations regardless of coinfection. Whether poor prognosis is associated with lymphocytopenia below the reference interval or absolute count is unclear.

COVID-19 patients have high concentrations of the acute phase response proteins (i.e., c-reactive protein [CRP] and ferritin) and inflammatory biomarkers (i.e., cytokines such as Interleukin-6; IL-6) at admission. 1,2 CRP is more widely available, and is a sensitive biomarker of inflammation and tissue damage that is increased at admission and during hospitalization. 2,4

Kidney injury prevalence (via creatinine measurement) at admission is unknown but 11-15% of hospitalized COVID-19 patients may have acute kidney injury. 1,2 Alanine 3/6 aminotransferase (ALT) elevations at admission range from 22% to 32% and cardiac injury (via cardiac troponin measurement) has been reported to range from 15% to 44%elevations at admission ranges from 22% to 32% and cardiac injury (via cardia troponin measurement) has been reported to range from 15% to 44%. [1] [2] [3] Other liver biomarkers are reported to be increased; however, ALT is more specific for liver injury and is also less affected by pre-analytical factors such as hemolysis etc.

Following recovery and 7-days post-convalescent plasma transfusion, CRP levels decreased by >10-fold, which was more pronounced than IL-6 and procalcitonin (~ 2fold difference). 4 Procalcitonin is a useful indicator for bacterial infections, though not all patients with COVID-19 have bacterial co-infections. 3,4

D-dimer and high-sensitivity cardiac troponin can also identify COVID-19 patients who are at low-and high-risk for death. 1,2,5 D-dimer is used in decision making for disseminated intravascular coagulation, deep vein thrombosis or pulmonary embolism and is given a high priority of testing in patients with COVID-19. 5 While for highsensitivity cardiac troponin, normal or low concentrations (typically below 5 ng/L, but cutoffs are assay specific) identifies patients at low-risk for cardiovascular outcomes and death in many different populations, including COVID-19 patients. 1,2

Two clinical scores that may also identify patients with COVID-19 at low-and highrisk for death are the sequential organ failure assessment (SOFA) score used in sepsis and the confusion, urea, respiratory rate, blood pressure, and age ≥ 65 years (CURB-65) score in the assessment of severity in patients with community acquired pneumonia. Both clinical scores require laboratory testing. Alanine Aminotransferase (ALT)  Using an overall cutoff of >40 U/L approximately 30% of COVID-19 patients had liver injury at admission. 1,3  The rate of liver injury could be higher in females as the upper limit of normal is typically lower in females as compared to males. D-dimer  At admission 50% of patients who survived had concentrations <0.6 ug/mL while the non-survivors at least 75% had concentrations >1.3 ug/mL. 1,2 High-sensitivity cardiac troponin  At admission, 50% of the survivors had a highsensitivity cardiac troponin I concentration ≤ 3 ng/L (a low normal level). 1,2 Clinical Scores  Creatinine, total bilirubin, pO 2 and platelet count are used for the SOFA (sequential organ failure assessment) score; while urea is used for the CURB-65 (confusion, urea, respiratory rate, blood pressure and age ≥65 years) score. 1 Lactate levels are also used to identify septic shockLactate is also used for septic shock.

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

Clinical characteristics of 113 deceased patients with coronavirus disease 2019: retrospective study

Covid-19 in critically ill patients in the Seattle region -case series

Treatment of 5 critically ill patients with COVID-19 with convalescent plasma

ISTH interim guidance on recognition and management of coagulopathy in COVID-19