E-gene RT-PCR Crossing Point Value and Other Biochemical Parameters as Useful Markers of Death Risk in COVID-19 Patients

Abstract

The identification of laboratory markers which predict the outcome of COVID-19 patients is a great concern. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) has been used to confirm the clinical diagnosis. The aim of this study is to evaluate laboratory parameters of COVID-19 patients as well as to evaluate the RT-PCR crossing point (Cp) value and correlate blood test abnormalities and the Cp value with patients survival. Two hundred thirty patients with positive RT-PCR of SARS-CoV-2 were included in the study. Molecular diagnosis of SARS-CoV-2 was performed by RT-PCR (LightMix, TibMolbiol, Germany). Clinical information, biochemical parameters and Cp values were collected in an anonymized database and variables were analyzed with SPSS v25.0 (IBM Corporation, Armonk, NY, USA). No-survivors were significantly older (>65 years old) than survivors (p=0.007). A higher prevalence of cardiovascular comorbidities in patients who died than in those who survived was found (p=0.002). Statistically significant differences were obtained comparing RT-PCR Cp values for the E-gene of patients who died and those who survived, being lower (<=28) those of patients who died (p=0.004). No-survivors had significantly higher levels of CRP (>100) (p=0.007). E-gene Cp values <=28, which correlate with a high number of copies of SARS-CoV-2, as well as several demographical and biochemical parameters (Age above 65 years old, CRP levels >100 mg/L or cardiovascular comorbidities) could be useful markers of death risk in these patients.

Keywords: COVID-19; Crossing point value; RT-PCR.