Diagnostic and Prognostic Value of Reticulated Platelet Fraction in Patients With Ventilator-Associated Pneumonia: A Prospective Observational Study
Conditions: Ventilator-Associated Pneumonia
Sponsor: Konya City Hospital

Study Protocol Document 
Study Title: Diagnostic and Prognostic Value of Reticulated Platelet Fraction in Patients 
With Ventilator-Associated Pneumonia: A Prospective Observational Study 
Protocol ID: KSH-RP-VAP-2025-01 
Version Number: 1.0 
Date: June 2025 
1. Background and Rationale 
Ventilator-associated pneumonia (VAP) is a common nosocomial infection in ICU patients 
undergoing mechanical ventilation for more than 48 hours. Traditional inflammatory 
markers like CRP and procalcitonin are commonly used but have limitations in early 
diagnosis. Reticulated Platelet Fraction (RP%) is an emerging biomarker with potential 
utility in early infection diagnosis and prognosis. This study aims to evaluate the diagnostic 
and prognostic value of RP% in VAP. 
2. Objectives 
Primary Objective: 
• 
- To assess the diagnostic accuracy of RP% in patients with VAP. 
Secondary Objectives: 
• 
- To evaluate the association between RP% and 28-day mortality. 
• 
- To explore correlations with SOFA scores and antibiotic de-escalation. 
3. Study Design 
This is a single-center, prospective observational cohort study to be conducted in a tertiary-
level ICU. Data will be collected prospectively from patients diagnosed with VAP. 
4. Population 
Inclusion Criteria: 
• 
- Age ≥18 years 
• 
- Mechanically ventilated >48 hours 
• 
- Diagnosed with VAP 
Exclusion Criteria: 
• 
- Pneumonia at ICU admission or as primary reason for intubation 
• 
- MV duration <48 hours 
• 
- Pregnancy or lactation 

• 
- Hematologic, oncologic, or autoimmune conditions within the past 4 weeks 
• 
- Immunosuppressive therapy or chemotherapy 
5. Data Collection and Laboratory Procedures 
RP% will be measured via Sysmex XN-1000 using EDTA blood samples, processed within 4 
hours. Routine lab values (CRP, PCT, WBCs, etc.) and clinical data (demographics, MV 
duration, SOFA scores) will be collected from electronic records. Serum for CRP and PCT 
will be processed via Roche Cobas 8000 after centrifugation. 
6. Sample Size 
Based on a predicted correlation coefficient (r=0.5) between RP% and PCT, a power 
analysis (α=0.05, power=0.95) using G*Power resulted in a required sample size of 38. 
Considering a dropout margin, a total of 42 patients will be enrolled. 
7. Statistical Analysis 
Data will be analyzed using SPSS v26. Normality will be assessed via Kolmogorov-Smirnov 
test. Comparisons will be made using independent samples t-test or Mann-Whitney U test 
for continuous variables, and Pearson chi-square for categorical data. Correlations will be 
examined using Pearson or Spearman correlation based on data distribution. A p-value 
<0.05 will be considered significant. 
8. Ethical Considerations 
Ethical approval was obtained from the institutional ethics committee of Konya City 
Hospital. Informed consent will be obtained from all patients' legal representatives. 
9. Study Timeline 
Start of enrollment: July 2025 
Estimated primary completion: January 2026 
Study end date: February 2026 
10. Principal Investigator 
Name: Dr. Hasan Şenay 
Institution: Konya City Hospital 
Email: drhasansenay@gmail.com 
Phone: +905055078822