# Utility of Serum Procalcitonin and Its Clearance in Predicting Outcomes in COVID-19 Patients

## TL;DR

This study explores how serum procalcitonin levels and their clearance can predict outcomes in severe or critical COVID-19 patients.

## Contribution

The study introduces the potential use of procalcitonin clearance as a predictive tool for patient outcomes in severe COVID-19.

## Key findings

- Non-survivors had significantly higher serum procalcitonin levels at admission compared to survivors.
- Non-survivors showed persistently elevated procalcitonin levels, while survivors showed a significant decrease.
- Procalcitonin clearance did not differ significantly between survivors and non-survivors.

## Abstract

Introduction

Identification of coronavirus disease 2019 (COVID-19) patients at risk of worse clinical outcomes is crucial to improving patient care. Various biochemical markers have been used to predict outcomes in such patients. We aimed to evaluate the role of serum PCT (procalcitonin) and the utility of PCT clearance (PCTc) in predicting the outcome of patients with COVID-19 illness.

Methods

We prospectively included 39 patients with severe or critical COVID-19 illness with an age equal to more than 18 years. In addition to routine baseline investigations, serum PCT was measured at admission (PCT1) and day 5 of hospitalization (PCT2). PCTc was calculated using the formula \begin{document}(PCTc (\%) = (PCT1-PCT2/PCT1) x 100)\end{document}.

Results

We observed that serum PCT at admission was significantly higher in non-survivors (median: 1.9 ng/ml IQR: 0.51-4.23) compared to survivors (median 0.35 (IQR: 0.1-1.2), p 0.002). On serial serum-PCT estimation, non-survivors had persistently elevated serum-PCT (median PCT1:1.9 ng/ml (IQR: 0.51-4.23) to median PCT2: 1.9ng/ml (IQR: 0.83-2.72), p 0.51) than survivors (median PCT1:0.35ng/ml (IQR: 0.1-1.19) to median PCT2: 0.15ng/ml (IQR: 0.05-0.29), p 0.01). However, no difference in serum PCTc was observed between the two groups (median: 35.3% (IQR: 12.5-84.9) in survivors vs. 71.7% (33.3-91.7) in non-survivors, p = 0.165).

Conclusion

Serum PCT is a potential biochemical marker that could predict outcomes in COVID-19 patients. Measurement of serial serum PCT and estimation of PCT clearance may serve as better predictors than a single value; however, well-designed studies are required to identify the definite role of serum PCT in COVID-19 patients of varying severity.