Does procalcitonin (PCT) increase post-operatively?

From the Guidelines

Procalcitonin (PCT) levels typically rise after surgery, even in the absence of infection, as a normal physiological response to surgical trauma and inflammation. This post-surgical elevation is a result of the release of inflammatory cytokines that stimulate PCT production from various tissues 1. PCT usually increases within 24-48 hours following surgery, with peak levels occurring around the second postoperative day. The magnitude of elevation depends on the type and extent of surgery, with major procedures like cardiac or abdominal surgeries causing higher PCT elevations than minor procedures. These non-infectious elevations generally remain below 2 ng/mL and decline rapidly within 48-72 hours if no infection develops.

Some key points to consider when interpreting PCT levels after surgery include:

• PCT is a useful biomarker for diagnosing surgical infections, with a sensitivity of 77% and a specificity of 79% for early diagnosis of sepsis in critically ill patients 1
• PCT can help clinicians in early discontinuation of antibiotics in critically ill patients and in patients undergoing intervention for acute peritonitis 1
• PCT levels are influenced by renal function, different techniques of renal replacement therapy, and neutropenia 1
• Understanding the normal post-surgical PCT pattern is important for clinicians, as persistently high or secondarily rising PCT levels beyond the expected timeframe may indicate a developing infection or complication requiring further investigation.

It's also important to note that while C-reactive protein (CRP) is also a useful biomarker for infection, it has a lower specificity than PCT and may not be as effective in differentiating between bacterial and non-bacterial infections 1. Overall, PCT is a valuable tool for clinicians to monitor patients after surgery and make informed decisions about antibiotic therapy and further investigation.

From the Research

Procalcitonin Levels After Surgery

• Procalcitonin (PCT) levels have been found to rise after surgery in several studies 2, 3, 4.
• The increase in PCT levels is influenced by the type of surgical procedure, with major abdominal, vascular, and thoracic surgery resulting in higher PCT levels compared to minor and aseptic surgery 2, 3.
• PCT levels typically peak on the first and second postoperative days and then decline rapidly 2, 3.
• The presence of systemic inflammatory response syndrome (SIRS) does not significantly affect PCT levels in patients after surgery 2.

Diagnostic Value of Procalcitonin

• Procalcitonin may be useful in identifying infection in trauma and post-operative acute care surgery, but its diagnostic value is limited by the fact that surgery and trauma alone can elevate PCT levels even in the absence of infection 5.
• Serial monitoring of PCT levels can help diagnose early postoperative infection after pediatric cardiac surgery, but its diagnostic properties are not observable during the first 3 postoperative days due to the inflammatory process related to cardiopulmonary bypass 6.
• The dynamic change of PCT is more important than the absolute value in predicting postoperative infection, and a second increase in PCT between the fourth and seventh postoperative day can be used as an indicator of postoperative infection 6.

Procalcitonin Levels in Specific Surgical Procedures

• Cardiac surgery can lead to a slight and transient increase in PCT levels on the first postoperative day, but significant elevation of PCT is only observed when complications are present 4.
• Intestinal surgery and major operations more often increase PCT levels, whereas minor and primarily aseptic surgery result in lower PCT levels 3.
• Thoracic surgery, including esophagectomy, can also lead to increased PCT levels 2.