Association of SARS-CoV-2 cycle threshold (Ct) values with clinical course and serum biomarkers in COVID-19 patients
İmran Sağlık, Beyza Ener, Halis Akalın, Buşra Ozdemir, Gökhan Ocakoğlu, Baris Yalcin, Uğur Önal, Özge Aydın Güçlü, Nilüfer Aylin Acet Öztürk, Ülkü Tüzemen, Ezgi Demirdöğen, Aslı Görek Dilektaşlı, Harun Ağca, Esra Kazak, Funda Çoşkun, Yasemin Heper, Melda Payaslıoğlu, Dane Ediger, Ahmet Ursavaş, Emel Yılmaz, Cüneyt Özakın, Esra Uzaslan, Mehmet Karadağ
Abstract
INTRODUCTION: Our knowledge has gaps regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication levels and its association to severity of Coronavirus disease 2019 (COVID-19). The aim of this study was to investigate the association of SARS-CoV-2 viral load with disease severity and serum biomarkers in COVID-19 patients. METHODOLOGY: Viral load was determined via cycle threshold (Ct) values of SARS-CoV-2 real-time reverse transcriptase-polymerase chain reaction (RT-PCR) in 214 adult patients. Ct values were compared with clinical severity, biochemical and hematological biomarkers. RESULTS: Clinical course of the disease was mild (49.1%), moderate (40.2%), and severe (10.7%). Median Ct value was 28.2 (IQR: 22.2-33.8) during the first week of the disease. Ct values were lower within five days after symptom onset [lowest Ct value on the third day (median: 24, IQR: 20.6-32.3)], but they increased significantly during the second and third weeks. No association was detected between admission Ct values and disease severity. Gender, age, co-morbidity, and mortality did not differ significantly in patients with low (≤ 25) and high (> 25) Ct values. White blood cell, neutrophil, platelet, and especially lymphocyte counts, were significantly lower in patients with low Ct values. CONCLUSIONS: No definitive/clear correlation between SARS-CoV-2 viral load and severity and mortality was found in the studied COVID-19 patients. However, neutrophil, platelet, and especially lymphocyte count were significantly lower in patients with a high viral load.