Adenosine deaminase in pleural effusion: Bridging diagnosis and the pathophysiology of inflammation

Table 2 Methodology workflow

Step	Content	Key details
Study design	Retrospective cohort study	Data collected from March 2015 to December 2019 at two hospitals in Rio de Janeiro, Brazil. Total patients: 157 (124 exudates, 33 transudates)
Inclusion criteria	Confirmed diagnosis of pleural effusion (exudates/transudates)	Exudates: n = 124 (79%); Transudates: n = 33 (21%)
Exclusion criteria	Absolute contraindications, hemolyzed PF, chronic renal failure, jaundice, unknown etiology, immunosuppressive medication use	Final cohort: 157 patients (after exclusions)
Sample size calculation	Based on MedCalc software (AUC > 0.50, α = 0.05, β = 0.20)	Required: 57 patients (19 exudates, 38 transudates); Actual: 157 patients
P-ADA assay	Kinetic method (Diazyme ADA kit)	Linear range: 0–200 U/L; Reference value: < 15 U/L (healthy adults)
Statistical analysis	ROC curve, Youden index, DeLong test, Hosmer–Lemeshow goodness-of-fit	AUC = 0.8107 (95%CI: 0.7174–0.8754), P < 0.0001

AUC: Area under the curve; P-ADA: Pleural adenosine deaminase; ROC: Receiver operating characteristic; PF: Pleural fluids.