Indian Journal of Critical Care Medicine

Register      Login

SEARCH WITHIN CONTENT

FIND ARTICLE

Volume / Issue

Online First

Archive
Related articles

VOLUME 25 , ISSUE 3 ( March, 2021 ) > List of Articles

ORIGINAL RESEARCH

Prognostic Value of “Cycle Threshold” in Confirmed COVID-19 Patients

B Rajyalakshmi, P Ramakrishna Reddy

Keywords : COVID-19, Cycle threshold, RT-PCR, Viral load

Citation Information : Rajyalakshmi B, Reddy PR. Prognostic Value of “Cycle Threshold” in Confirmed COVID-19 Patients. Indian J Crit Care Med 2021; 25 (3):322-326.

DOI: 10.5005/jp-journals-10071-23765

License: CC BY-NC 4.0

Published Online: 20-03-2021

Copyright Statement:  Copyright © 2021; Jaypee Brothers Medical Publishers (P) Ltd.


Abstract

Objective: To study the correlation between the cycle threshold (CT) of reverse transcription–polymerase chain reaction (RT–PCR) test in confirmed COVID-19 patients and the severity of disease. Background: RT–PCR test is a standard method for the diagnosis of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections. This test is based upon the amplification of the fluorescent signal. The number of cycles that the fluorescent signal undergoes to reach the threshold is called “cycle threshold.” It is inversely related to the nucleic acid content of the sample. Patients and methods: This is a single-centered, retrospective observational study. We have included a total of 192 patients. SARS-CoV-2 infection was confirmed by the RT–PCR test. Entire data have been collected from the electronic medical records. The primary outcome was 28-day mortality, whereas the secondary outcomes were intensive care unit (ICU) admission, invasive ventilation, acute kidney injury, renal replacement therapy (RRT), shock, and COVID-19 reporting and data system (CO-RADS) score on high-resolution computed tomography of the chest, total length of stay in the hospital, and the number of ICU days and ventilator days. Results: We have calculated the mean CT value for all groups and calculated the p-value for statistical significance. For the total length of stay in the hospital and the number of ICU days and ventilator days, we applied the Pearson correlation coefficient. The p-value was statistically significant for mortality, ICU admission, and shock groups. The CT values and the length of ICU stay were inversely correlated with the statistically significant p-value. Conclusion: Low CT value is associated with increased ICU admission, high mortality, shock, and increased length of ICU stay.


  1. Hoffmann M, Kleine-Weber H, Schroeder S, Kruger N, Herrler T, Erichsen S, et al. SARS-CoV-2 cell entry depends on ACE2 and TMPRSS2 and is blocked by a clinically proven protease inhibitor. Cell 2020;181(2):271–280. DOI: 10.1016/j.cell.2020.02.052.
  2. Zou X, Chen K, Zou J, Han P, Hao J, Han Z. Single-cell RNA-seq data analysis on the receptor ACE2 expression reveals the potential risk of different human organs vulnerable to 2019-nCoV infection. Front.Med. 2020;14(2):185–192. DOI: 10.1007/s11684-020-0754-0.
  3. Wiersinga WJ, Rhodes A, Cheng AC, Peacock SJ, Prescott HC. Pathophysiology, transmission, diagnosis, and treatment of coronavirus disease 2019 (COVID-19). JAMA 2020;324(8):782–793. DOI: 10.1001/jama.2020.12839.
  4. Tang N, Li D, Wang X, Sun Z. Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia. J Thromb Haemost 2020;18:844–847. DOI: 10.1111/jth.14768.
  5. Tang YW, Schmitz JE, Persing DH, Stratton CW. 2020. Laboratory diagnosis of COVID-19: current issues and challenges. J Clin Microbiol 2020;58:512–520. DOI: 10.1128/JCM.00512-20.
  6. LeBlanc JJ, Gubbay JB, Li Y, Needle R, Arneson SR, Marcino D, et al. Real-time PCR-based SARS-CoV-2 detection in Canadian laboratories. J Clin Virol 2020;128:104433. DOI: 10.1016/j.jcv.2020.104433.
  7. Tom MR, Mina MJ. To interpret the SARS-CoV-2 test, consider the cycle threshold value. Clin Infect Dis 2020. DOI: 10.1093/cid/ciaa619.
  8. Chang MC, Hur J, Park D. Interpreting the COVID-19 test results: a guide for physiatrists. Am J Phys Med Rehabil 2020. DOI: 10.1097/PHM.0000000000001471.
  9. Ng EKO, Hui DS, Allen Chan KC, Hung ECW, Chiu RWK, Lee N, et al. Quantitative analysis and prognostic implication of SARS coronavirus RNA in the plasma and serum of patients with severe acute respiratory syndrome. Clin Chem 2003;49(12):1976–1980. DOI: 10.1373/clinchem.2003.024125.
  10. Kermali M, Khalsa RK, Pillai K, Ismail Z, Harky A. The role of biomarkers in the diagnosis of COVID-19—a systematic review. Life Sci 2020;254:117788. DOI: 10.1016/j.lfs.2020.117788.
  11. Liu F, Li L, Xu M, Wu J, Luo D, Zhu Y, et al. Prognostic value of interleukin-6, C reactive protein, and procalcitonin in patients with COVID-19. J Clin Virol 2020;127. DOI: 10.1016/j.jcv.2020.104370.
  12. Tan L, Wang Q, Zhang D, Ding J, Huang Q, Tang YQ, et al. Lymphopenia predicts disease severity of COVID-19: a descriptive and predictive study, Signal Transduct Target Ther 2020;5:33. DOI: 10.1038/s41392-020-0148-4.
  13. Liao YC, Liang WG, Chen FW, Hsu JH, Yang JJ, Chang MS. IL-19 induces production of IL-6 and TNF-and results in cell apoptosis through TNF. J Immunol 2002;169:4288–4297. DOI: 10.4049/jimmunol.169.8.4288.
  14. Fischer K, Hoffmann P, Voelkl S, Meidenbauer N, Ammer J, Edinger M, et al. Inhibitory effect of tumor cell derived lactic acid on human T cells. Blood 2007;109:9. DOI: 10.1182/blood-2006-07-035972.
  15. Zheng S, Fan J, Yu F, Feng B, Lou B, Zou Q, et al. Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January–March 2020: a retrospective cohort study. BMJ 2020;369. DOI: 10.1136 bmj.m1443.
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.