Role of Serum Procalcitonin Levels in Solid-Organ Transplant Patients

Systemic infection is among the common complications after solid-organ transplant and is associated with increased mortality and morbidity. Because it has prognostic significance, timely diagnosis and treatment are crucial. Procalcitonin is a propeptide of calcitonin and has been increasingly used as a biomarker of bacterial infection. Here, we investigated procalcitonin's role in identifying infectious complications in solid-organ transplant recipients.

We retrospectively evaluated the records of 86 adult patients who underwent solid-organ transplant (between 2011 and 2015) with procalcitonin levels determined at our center. Clinical and demographic variables and laboratory data were noted. Relation between C-reactive protein and procalcitonin serum levels were compared in patients who were diagnosed as having pneumonia on clinical, microbiologic, and radiologic findings.

Mean age of our patients was 45.5 ± 13.4 years (range, 18-70 y), with 61 male patients (70.9%). We included 26 liver, 44 kidney, 14 heart, and 2 heart and renal transplant recipients. Procalcitonin was positive in 43 patients (50%). Of the 39 patients who were diagnosed with pneumonia, procalcitonin was positive in 18 patients (46.2%). There was a significant correlation between serum levels of procalcitonin and C-reactive protein (r = 0.45; P < .001) and neutrophil count (r = 0.24; P = .025). There was no correlation between mortality and procalcitonin level, CRP level, or leukocyte count (P > .05).

Our findings indicate that procalcitonin is a promising biomarker to detect infectious complications in transplant recipients. Physical examination and radiologic findings of bacterial pneumonia may be nonspecific, and in a considerable number of immunocompromised patients the site of infection could not be identified. Serum levels of procalcitonin should not be used as sole criteria for clinical decision making; however, it can guide us in therapy of such conditions in addition to currently used serum markers of infection.