Diagnostic Value and Prognostic Significance of Laboratory Parameters in Adult COVID-19 Patients Admitted to the Intensive Care Unit by Age Group

Year 2026, Volume: 16 Issue: 1, 11 - 16, 19.03.2026

Murat Genç , Bensu Bulut , Medine Akkan Öz , Ayşenur Gür Hüseyin Mutlu Ramiz Yazıcı , Dilek Atik , Betül Çiğdem Yortanlı , Eyüp Sarı Mehmet Yortanlı

https://izlik.org/JA97DH45BK

Abstract

Aim: COVID-19 presents with heterogeneous clinical manifestations and
laboratory findings across different age groups. This study aimed to investigate
the diagnostic and prognostic value of laboratory parameters in adult
patients with COVID-19 admitted to the Intensive Care Unit, with particular
emphasis on age groups.
Materials and methods: This retrospective study included 283 PCRconfirmed
COVID-19 patients admitted to intensive care at Ankara
Yenimahalle Training and Research Hospital between March 15 and June 15,
2020. Patients were divided into four age groups: middle-aged (45–59 years,
n=49), elderly (60–74 years, n=101), advanced elderly (75–89 years, n=122),
and very elderly (≥90 years, n=11). Demographic data, clinical outcomes, and
laboratory parameters were collected and analysed. The predictive value of
laboratory parameters for mortality was assessed using ROC curve analysis.
Results: Significant differences were observed in clinical outcomes across
age groups, with the highest discharge rate in the 75–89 age group and
lower rates in both the 45–59 and ≥90 age groups (p <0.05). Laboratory
parameters, including WBC, neutrophils, platelets, monocytes, MPV, RDW,
ferritin, CRP, procalcitonin, and D-dimer, showed significant differences
across age groups (p<0.05). ROC curve analysis identified CRP (cut-off:
120.8 mg/L, sensitivity: 63.5%, specificity: 61%, AUC: 0.679) and D-dimer
(cut-off: 1795 ng/mL, sensitivity: 91.8%, specificity: 72%, AUC: 0.627) as
significant predictors of mortality in COVID-19 patients over 45 years.
Conclusion: This study demonstrates that CRP and D-dimer are reliable
biomarkers for predicting mortality in elderly COVID-19 patients who require
intensive care. The unexpected result that the advanced elderly group
(75–89 years) had more favourable outcomes than both the younger (45–59)
and the very elderly (≥90) groups was notable. These findings suggest that
age-specific laboratory reference values may improve risk assessment and
clinical management of COVID-19 patients in intensive care settings

Keywords

COVID-19 , biomarkers , intensive care , C-reactive protein , D-dimer , mortality , elderly patients

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