Can this result diagnose a condition on its own?

No. Laboratory results are interpreted with symptoms, medical history, specimen conditions and related tests.

Which reference range should I use?

Start with the performing laboratory's own reference interval; clinical cutoffs, when relevant, are separate sourced thresholds used for a specific purpose.

When should I discuss the result with a healthcare professional?

Results that are clearly outside range, persistent, symptomatic or unexpected should be reviewed by a healthcare professional. If you have emergency symptoms such as chest pain, severe shortness of breath, fainting, new neurologic symptoms or severe illness, seek urgent assessment rather than waiting for a laboratory result.

Information about a laboratory test

Procalcitonin: What Does This Test Measure?

The Procalcitonin test measures the level of procalcitonin in blood.

Test summary

Test name: Procalcitonin
Abbreviations: PCT
Category: Inflammation / Infection
Panel: Infection / Sepsis Assessment
Specimen: Serum / plasma
Common units: ng/mL, µg/L

What does the test measure?

The Procalcitonin test measures the level of procalcitonin in blood.

Why is the test ordered?

It may be ordered to help assess serious bacterial infection or sepsis and to provide additional information about severity and clinical course.

Information about a low result

A low value is usually not interpreted as a clinical problem by itself; the purpose of testing and laboratory context matter.

Information about a high result

High procalcitonin can increase concern for serious systemic bacterial infection or sepsis, but it may also rise after major surgery, trauma and some noninfectious conditions.

Reference and clinical context

Start with the performing laboratory's reference interval, unit, specimen type and method. Numeric information on this page is stored as sourced example intervals or clinical thresholds.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

Procalcitonin does not prove sepsis or identify the organism by itself. Serial values, kidney function, the clinical picture, CRP and sometimes lactate provide additional context.

Related specialties

Infectious Diseases
Internal Medicine
Emergency Medicine

Frequently asked questions

More information about this test

Procalcitonin: High Result: What Does It Mean?

Sources

C-Reactive Protein (CRP) Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2025 · CRP testing, inflammation and nonspecific interpretation · Verified: Aug 12, 2026
Procalcitonin Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2025 · Procalcitonin, systemic bacterial infection and sepsis context · Verified: Aug 12, 2026
Lactate Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Lactate testing in perfusion, hypoxia and severe-illness contexts · Verified: Aug 12, 2026