What can cause falsely elevated serum procalcitonin (PCT) levels?

From the Guidelines

Falsely elevated serum procalcitonin levels can occur due to several non-infectious conditions, including severe trauma, major surgery, burns, and certain malignancies, as well as technical laboratory interference and some medications. When interpreting procalcitonin (PCT) levels, it is essential to consider these potential causes of false elevation to avoid unnecessary antibiotic treatment. Some of the key factors that can lead to falsely elevated PCT levels include:

• Severe trauma, major surgery, and burns, which can cause a systemic inflammatory response that elevates PCT levels 1
• Certain malignancies, such as medullary thyroid carcinoma and small cell lung cancer, which can autonomously produce PCT
• Autoimmune disorders like vasculitis and systemic lupus erythematosus, which may also elevate PCT levels
• Technical laboratory interference, such as heterophilic antibodies or cross-reactivity with other substances
• Some medications and treatments, including certain immunotherapies, granulocyte transfusions, and OKT3 antibodies It is crucial to contextualize PCT results with the patient's clinical picture to avoid misinterpretation and unnecessary treatment. In the context of COVID-19, studies have shown that PCT levels can be elevated in patients without bacterial pneumonia, highlighting the need for careful interpretation of PCT results in this population 1.

From the Research

Falsely Elevated Serum Procalcitonin Levels

Several factors can cause falsely elevated serum procalcitonin (PCT) levels, including:

• Surgery and trauma alone, even in the absence of infection 2
• Non-infectious febrile episodes related to administration of certain medications, such as T-cell antibodies, alemtuzumab, interleukin-2, and prophylactic donor granulocyte transfusions 3
• Acute graft-versus-host disease (aGvHD) 3
• Certain hematologic and oncologic disorders 3

Clinical Conditions Affecting PCT Levels

PCT levels can be affected by various clinical conditions, including:

• Sepsis and systemic inflammatory response syndrome (SIRS) 4, 5, 6
• Bacteremia 4
• Organ dysfunction and failure 6
• Major trauma 6

Limitations of PCT as a Diagnostic Marker

PCT has limitations as a diagnostic marker of sepsis, particularly in certain clinical conditions, such as:

• Hemato-oncological patients 3
• Patients receiving T-cell-directed immunomodulatory treatment, granulocyte support, or experiencing acute GvHD 3