Longitudinal monitoring of laboratory markers characterizes hospitalized and ambulatory COVID-19 patients

Velavan, Thirumalaisamy P.; Kuk, Salih; Linh, Le Thi Kieu; Lamsfus Calle, Carlos; Lalremruata, Albert; Pallerla, Srinivas Reddy; Kreidenweiss, Andrea; Held, Jana; Esen, Meral; Gabor, Julian; Neurohr, Eva Maria; Shamsrizi, Parichehr; Fathi, Anahita; Biecker, Erwin; Berg, Christoph P.; Ramharter, Michael; Addo, Marylyn Martina; Kreuels, Benno; Kremsner, Peter G.

Early detection of severe forms of COVID-19 is absolutely essential for timely triage of patients. We longitudinally followed-up two well-characterized patient groups, hospitalized moderate to severe (n = 26), and ambulatory mild COVID-19 patients (n = 16) at home quarantine. Human D-dimer, C-reactive protein (CRP), ferritin, cardiac troponin I, interleukin-6 (IL-6) levels were measured on day 1, day 7, day 14 and day 28. All hospitalized patients were SARS-CoV-2 positive on admission, while all ambulatory patients were SARS-CoV-2 positive at recruitment. Hospitalized patients had higher D-dimer, CRP and ferritin, cardiac troponin I and IL-6 levels than ambulatory patients (p < 0.001, p < 0.001, p = 0.016, p = 0.035, p = 0.002 respectively). Hospitalized patients experienced significant decreases in CRP, ferritin and IL-6 levels from admission to recovery (p < 0.001, p = 0.025, and p = 0.001 respectively). Cardiac troponin I levels were high during the acute phase in both hospitalized and ambulatory patients, indicating a potential myocardial injury. In summary, D-dimer, CRP, ferritin, cardiac troponin I, IL-6 are predictive laboratory markers and can largely determine the clinical course of COVID-19, in particular the prognosis of critically ill COVID-19 patients.