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Procalcitonin Test

⚠️ Update approaching🔬 Evidence: StrongInternal Medicine
Diğer adları: PCT, Procalcitonin level
⚠️

Discuss your test results with your doctor. This page is for informational purposes only and does not provide a diagnosis.

⚡ Key Facts

• A biomarker that rises significantly in bacterial infections • Healthy individuals: <0.05 ng/mL • Helps distinguish bacterial from viral infections • Used to guide antibiotic therapy duration

🧪 What Does This Test Measure?

The procalcitonin test measures a biomarker that is normally produced in negligible amounts but rises markedly during systemic bacterial infections.

📋 Why Is It Ordered?

Ordered for bacterial infection and sepsis evaluation, antibiotic therapy guidance, and monitoring treatment response in critical care settings.

🔧 Preparation

No special preparation is required. Can be measured at any time in emergency settings. Result turnaround time may vary.

📊 Reference Ranges

Healthy individuals: <0.05 ng/mL Low risk: <0.1 ng/mL Systemic infection possible: 0.5–2 ng/mL Sepsis likely: 2–10 ng/mL Severe sepsis/shock: >10 ng/mL ⚠️ Thresholds are approximate and vary by clinical context.

⬆️ High Values

Elevated procalcitonin may be associated with bacterial infection, sepsis, severe trauma, major surgery, or rare non-infectious causes.

⬇️ Low Values

Low procalcitonin generally suggests that systemic bacterial infection is unlikely. However, localized infections may not always elevate procalcitonin.

⚙️ What Can Affect Results?

Infection type and severity, surgery and trauma, kidney function, immunosuppression, and timing of measurement may affect procalcitonin results.

🔬 Evidence Summary

Strong evidence: 1 guideline, 1 systematic review, and 3 reviews.

📚 Most Important Studies on This Topic

1

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021

Guideline· Critical Care Medicine · 2021 · PMID: 34599691

2

Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections

Systematic review· Cochrane Database of Systematic Reviews · 2017 · PMID: 29025194

3

Procalcitonin-guided antibiotic therapy algorithms for different types of acute respiratory infections based on previous trials

Review· Expert Review of Anti-infective Therapy · 2018 · PMID: 29969320

✅ Key Takeaways

💡

What you learned: Procalcitonin is one of the most specific biomarkers for bacterial infection. It is used to guide antibiotic decisions and assess sepsis severity.

⛔

A procalcitonin result alone cannot confirm or exclude bacterial infection. Clinical presentation and other findings are essential.

🔬 Sources Used on This Page

5 sources · Most recent publication: 2021
📋
Guideline
Expert society and guideline recommendations
1
source
📊
Systematic review / meta-analysis
Combined analysis of multiple studies
1
source
📖
Review
Comprehensive topic evaluation
3
sources
Overall assessment: Evidence level for this topic is strong. This page is supported by 1 guideline, 1 systematic review/meta-analysis, 3 reviews.

📝 Questions to Ask Your Doctor

Be prepared for your appointment. Add questions to your list.

📋 References

[PMID: 34599691] Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Critical Care Medicine, 2021.
[PMID: 29969320] Procalcitonin-guided antibiotic therapy algorithms for different types of acute respiratory infections based on previous trials. Expert Review of Anti-infective Therapy, 2018.
[PMID: 29025194] Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections. Cochrane Database of Systematic Reviews, 2017.
[PMID: 21936959] Procalcitonin for diagnosis of infection and guide to antibiotic decisions: past, present and future. BMC Medicine, 2011.
[PMID: 9971870] Acute-phase proteins and other systemic responses to inflammation. New England Journal of Medicine, 1999.
Last reviewed: 4/2/2026
Next review: 4/2/2027

🔗 Related Topics

🧪 CRP (C-reaktif protein — genel enflamasyon belirteci)🧪 Sedimantasyon (ESR — nonspesifik enflamasyon belirteci)🧪 Hemogram (beyaz küre sayısı ve diferansiyel)🧪 Ferritin (akut faz proteini olarak da yükselir)🧪 Kreatinin (böbrek fonksiyonu — PCT klirensi etkiler)
⚖️ This page does not replace medical advice. Make treatment decisions with your doctor.
Content is based on scientific studies indexed in PubMed and current clinical guidelines.