Relationship of Viral Load with the Laboratory Markers and Prognosis in COVID-19 Patients

Background: Coronavirus disease 2019 (COVID-19) viral load determined from the cycle threshold (CT) values may be a marker of disease severity and predict disease progression. Our study aimed to investigate the relationship between SARS-CoV-19 cycle thresholds or viral load, laboratory markers, and patient prognosis.

Methods: Patients who were admitted to Imam Reza Hospital at Mashhad University of Medical Sciences between March 2020 and March 2021 and had COVID-19 polymerase chain reaction (PCR)-confirmed at random were included in this cross-sectional study. Patients were randomly selected from those who tested positive on nasopharyngeal and oropharyngeal reverse transcription-PCR samples. The inclusion criteria were all patients older than 16 years with positive COVID-19 PCR results. Samples with Ct values of ≤36 were considered positive for SARS-CoV-2 RNA. Patients who did not have laboratory markers were excluded. We used SPSS Version 16 (Pearson correlation, analysis of variance, and logistic regression tests) to analyze the data. A ≤ 0.05 was considered statistically significant.

Results: In our study, serum lactate dehydrogenase and aspartate aminotransferase were found to be laboratory biomarkers inversely correlated with COVID-19 Ct values, indicating higher viral load (r = -0.14; = 0.024 and r = -0.12; = 0.053, respectively). Also, the platelet count is lower in patients with higher viral loads (r = 0.18; < 0.001). However, we found no correlation between the viral load and some laboratory biomarkers such as ferritin, white blood cell and lymphocyte count, alanine transaminase, and c-reactive protein ( > 0.05). The patient's length of hospital stay was not correlated with their viral load ( > 0.05).

Conclusion: The COVID-19 viral load has been linked to some laboratory indicators and may be used to predict patient death. These discoveries might help in the treatment of COVID-19 disease.