How high does my procalcitonin (PCT) need to be to be dangerous?

Do not wait and seek emergency care or call emergency services if you have any of the following: very high fever with rapid or difficult breathing, fainting or major change in consciousness, persistent vomiting, severe dizziness, extreme weakness, very low blood pressure, very fast heart rate, or rapid overall worsening.

• Rapid or difficult breathing
• Change in consciousness or fainting
• Very low blood pressure or dizziness
• High fever with rapidly worsening condition

These signs indicate a medical emergency; PCT value does not change the need for prompt assessment.

Procalcitonin is a blood marker that often rises in bacterial infections and systemic inflammation. It tends to be lower in viral infections. PCT alone does not confirm a diagnosis; it must be interpreted alongside clinical findings and other tests.

• Often elevated in bacterial infections
• Usually lower in viral infections
• Not diagnostic on its own

Laboratory reference ranges can differ between facilities.

Practical threshold values used in many settings are approximate and should be combined with clinical judgment.

• <0.05 ng/mL: generally considered low/normal
• 0.05–0.5 ng/mL: mild increase possible
• 0.5–2 ng/mL: increased suspicion for significant bacterial infection
• >2 ng/mL: greater likelihood of serious bacterial infection or systemic response such as sepsis

These values are guidance only. Use your lab's reference range and your clinician's interpretation.

If your PCT is raised, suitable specialists for further assessment include Infectious Diseases and Clinical Microbiology, Internal Medicine, or Intensive care teams depending on severity. For appointments or emergency assessment, have the PCT value and test date, any symptoms (fever, breathing problems, blood pressure changes, altered consciousness), other laboratory or imaging results, and a list of current medications and chronic conditions ready.

• PCT value and test date
• Symptoms such as fever, shortness of breath, changes in consciousness
• Other lab tests and imaging results (if available)
• Chronic conditions and current medications

These are clinical navigation suggestions and not a substitute for diagnosis or treatment.