ORIGINAL ARTICLES
IMAJ | volume 27
Journal 12, December 2025
pages: 795-799
Association Between RT-PCR Cycle Threshold and Outcomes of Individuals Hospitalized for COVID-19
1 Division of Pulmonology Medicine, Barzilai University Medical Center, Ashkelon, Israel
2 Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
3 Department of Nephrology and Hypertension, Meir Medical Center, Kfar Saba, Israel
4 Gray Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel
5 Department of Epidemiology, Biostatistics and Community Health Sciences, School of Public Health, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
6 Institute of Pulmonary Medicine, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
7 Medical Office of Southern District, Ministry of Health, Ashkelon, Israel
Summary
Background:
Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to a wide spectrum of clinical severity. The gold standard diagnosis of infection is reverse transcription polymerase chain reaction of nasopharyngeal swabs, which also provides a semiquantitative assessment of viral loads by measuring cycle threshold (CT) values.
Objective:
To assess whether CT values at admission can predict mortality and oxygen needs among individuals hospitalized for coronavirus disease 2019 (COVID-19).
Methods:
The retrospective study included adults hospitalized for COVID-19 between 1 August 2020 and 30 April 2021 at Barzilai University Medical Center. Patients were categorized according to initial CT values as high (≥ 25) or low (< 25) values. The primary outcome was the association between CT values during admission and overall mortality.
Results:
The study group included 636 patients, with a mean age of 67.2 years, 54.4% males. Overall mortality of patients with CT values < 25 was significantly higher (odds ratio for mortality 1.78 vs. patients with CT ≥ 25,
P = 0.002). Significantly more patients in the low CT group required oxygen support than in the high CT group, 50% vs. 31.9% (
P < 0.001). An inverse association between CT values and mortality rates remained significant in multivariate regression analysis, such that a 1-unit decrease in CT was associated with a 6% increased mortality.
Conclusions:
Lower CT values at admission were associated with increased mortality among patients hospitalized for COVID-19. CT values can be used to predict outcomes among such patients.