Consideration of the Cycle Threshold Values from Real-Time RT-PCR SARS-CoV-2 Interpretation for the Clinicians: Analysis of 339 Positive Cases from a Referral Laboratory in Jakarta, Indonesia
Background: real-time RT-PCR was recommended by WHO for COVID-19 diagnosis. The cycle threshold (Ct) values were expected to have an association with clinical manifestation. However, the diagnostic modalities such as quantitative molecular detection and virus isolation were not yet available for the routine test. This study has been conducted to analyze the relationship between the Ct values of qualitative rRT-PCR and the clinical manifestation and to describe the factors determining the result. Methods: from March to April 2020, specimens were sent to our laboratory from different healthcare centers in Jakarta. The patient’s characteristic and clinical manifestation were extracted from the specimen’s epidemiology forms. The specimens extracted and tested using rRT-PCR, and the Ct value were collected. The data were analyzed using the appropriate statistic test. Results: from 339 positive results, the mild to moderate case was 176 (52%) and the severe cases was 163 (48%). Female was dominant in the mild to moderate cases (58%), while the male was prevalent in the severe cases (60%). The median age for mild to moderate case was 35 years old and severe cases was 49 years old. Statistical analysis found relationship between both group with gender (p = 0.001) and age (p < 0.001), but not with the Ct value. Conclusion: many variables in specimen sampling and processing could affect the Ct value result. In addition, the disease’s severity was depended with the host immune response, regardless the number of virus. There was suggested no significant difference between the Ct values of mild-moderate and severe COVID-19, and thus should not be loosely interpreted.
World Health Organization. Laboratory testing for coronavirus disease 2019 (COVID-19) in suspected human cases: Interim guidance, 2 march 2020.
Yu X, Sun S, Shi Y, Wang H, Zhao R, Sheng J. SARS-CoV-2 viral load in sputum correlates with risk of covid-19 progression. Critical Care. 2020;24(1):170.
Zou L, Ruan F, Huang M, et al. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. New Engl J Med. 2020;382(12):1177-9.
Tom MR, Mina MJ. To interpret the SARS-CoV-2 test, consider the cycle threshold value. Clinical Infectious Diseases. 2020.
Bullard J, Dust K, Funk D, et al. Predicting infectious SARS-CoV-2 from diagnostic samples. Clinical Infectious Diseases. 2020.
National Centre for Infectious Disease. Position statement from the National Centre for Infectious Diseases and the Chapter of Infectious Disease Physicians, Academy of Medicine, Singapore: period of infectivity to inform strategies for de-isolation for COVID-19 patients. https://www.ncid.sg/Documents/Period%20of%20Infectivity%20Position%20Statementv2.pdf. 2020 (Accessed 24 June 2020).
Han MS, Byun J-H, Cho Y, Rim JH. RT-PCR for SARS-CoV-2: Quantitative versus qualitative. Lancet Infect Dis. 2020:S1473-3099(20)30424-2.
Gao Z, Xu Y, Sun C, et al. A systematic review of asymptomatic infections with COVID-19. J Microbiol Immunol Infect. 2020.
Tian S, Hu N, Lou J, et al. Characteristics of COVID-19 infection in Beijing. J Infect. 2020.
Young BE, Ong SWX, Kalimuddin S, et al. Epidemiologic features and clinical course of patients infected with SARS-CoV-2 in Singapore. J Am Med Assoc. 2020;323(15):1488-94.
Gottlieb M, Sansom S, Frankenberger C, Ward E, Hota B. Clinical course and factors associated with hospitalization and critical illness among COVID-19 patients in Chicago, Illinois. Acad Emerg Med. 2020;27(10):963-73.
Tan L, Kang X, Ji X, et al. Validation of predictors of disease severity and outcomes in COVID-19 patients: a descriptive and retrospective study. Med. 2020.
Qian M, Yi Q, Qihua F, Ming G. Understanding the influencing factors of nucleic acid detection of 2019 novel coronavirus. Chin J Lab Med. 2020;10.
Piralla A, Giardina F, Rovida F, Campanini G, Baldanti F. Cellular DNA quantification in respiratory samples for the normalization of viral load: a real need? J Clin Virol. 2018;107:6-10.
Carmo A, Pereira-Vaz J, Mota V, et al. Clearance and persistence of SARS-CoV-2 RNA in patients with COVID-19. J Med Virol. 2020;92(10):2227-31.
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