Evaluating the use of procalcitonin as a biomarker for infection in a medical intensive care unit

Purpose: The primary objective of this study was to determine if the utilization of procalcitonin (PCT) levels resulted in decreased antibiotic usage.  The secondary objectives were to determine if the utilization of PCT levels resulted in a decreased hospital and medical intensive care unit (MICU) length of stay, decreased adverse events, timely resolution of infection and any difference in mortality.

Methods: This study was a retrospective chart review that compared adult patients who had a PCT level ordered versus a control group of patients, who did not have a PCT level ordered in the MICU.  Patients were included into the study if they were >18 years of age who were admitted to the MICU and treated with antibiotics.  Patients were excluded if they were under the age of 18, pregnant, received antifungal agents, immunocompromised, had metastatic cancer or did not have antibiotics ordered during their stay in the MICU.  The following data was collected: sex, age, ICD-9 codes, PCT level, total number of days on antibiotic therapy, adverse events reported, total hospital length of stay, total MICU length of stay, mortality and time to resolution of infection. 

Results: Both groups of patients had similar age and sex ratio.  Patients who had a PCT level measured had a significantly greater total number of days on antibiotics (median 9.5 vs. 6.0 days; p<0.0001), greater total number of hospital days (median 18.5 vs. 10.0; p<0.0004), greater total number of MICU days (median 3.0 vs. 2.0; p<0.003) and higher incidence of adverse events (16.7% vs. 4.2%; p<0.042) compared to patients without PCT levels measured.  There was no difference shown in time to resolution of infection and mortality. 

Conclusion: PCT did not decrease antibiotic usage in a MICU.  Furthermore, the biomarker did not assist in decreasing the length of hospital stay or intensive care unit length of stay.