What is the role of presepsin in differentiating between infection and disease flare-ups in patients with rheumatic disorders?

Role of Presepsin in Differentiating Infection in Rheumatic Disorders

Presepsin is a valuable biomarker for differentiating bacterial infection from disease flare-ups in patients with rheumatic disorders, demonstrating higher specificity than C-reactive protein while maintaining good sensitivity. 1

Understanding Presepsin as a Biomarker

• Presepsin (soluble CD14 subtype or sCD14-ST) is an emerging immunologic biomarker that shows promise in early detection of bacterial infections 2
• It is produced during bacterial phagocytosis and believed to function as a regulatory molecule of the adaptive immune system 2
• Presepsin levels rise early during bacterial infections, making it an attractive indicator for laboratory testing in clinical settings 2

Diagnostic Accuracy in Rheumatic Disorders

• In patients with rheumatoid arthritis (RA), presepsin levels are significantly higher in those with bacterial infection compared to those with non-infectious inflammation, even when C-reactive protein (CRP) is elevated 1
• A study of RA patients showed presepsin levels in the infection group (682.8 ± 158.1 pg/mL) were significantly higher than in the CRP-positive non-infection group (192.0 ± 12.0 pg/mL) 1
• Receiver operating characteristic (ROC) analysis demonstrates that presepsin has higher diagnostic accuracy for infection in RA patients than traditional markers like CRP or white blood cell count 1

Comparison with Other Biomarkers

• Presepsin shows comparable or better performance than procalcitonin (PCT) in differentiating bacterial infections from disease activity in rheumatic disorders 1
• In systemic lupus erythematosus (SLE) patients, presepsin demonstrated higher specificity (87.5%) than high-sensitivity CRP (60.4%) with equal sensitivity (80.4%) for detecting bacterial infections 3
• A meta-analysis showed presepsin has very good overall diagnostic accuracy (AUC=0.89) for sepsis diagnosis in patients with systemic inflammation 4

Clinical Application in Rheumatic Disease Management

• Presepsin can help guide treatment decisions when clinicians need to differentiate between infection and disease flare, which is critical since immunosuppressive therapies used for flares may worsen infections 5
• The biomarker correlates with infection severity as measured by Sequential Organ Failure Assessment (SOFA) Score, providing prognostic information in addition to diagnostic value 1
• Early identification of infection using presepsin can help prevent inappropriate escalation of immunosuppressive therapy in patients experiencing infection rather than disease flare 5

Limitations and Considerations

• Presepsin levels may be affected by kidney function, with less reliable results in patients with advanced acute kidney injury (AKI) 6
• While presepsin remains useful in patients with no AKI or less severe forms of AKI, its diagnostic value decreases in patients with more advanced kidney dysfunction 6
• Different cutoff values may be needed depending on kidney function: 670 pg/mL for non-AKI patients (sensitivity 70.3%, specificity 81.3%) versus 864 pg/mL for AKI patients (sensitivity 71.4%, specificity 63.8%) 6

Practical Implementation

• Consider presepsin testing when faced with diagnostic uncertainty between infection and disease flare in rheumatic patients, particularly when traditional markers like CRP are elevated 1, 3
• Interpret presepsin results in conjunction with clinical assessment and other biomarkers for optimal diagnostic accuracy 2
• Use presepsin as part of the decision-making process when considering whether to continue, initiate, or withhold immunosuppressive therapies in patients with suspected infection 5
• Be aware that presepsin levels may need different interpretation in patients with significant kidney dysfunction 6