关键词: 肺部感染, 降钙素原, 菌血症

Abstract:

Objective To investigate the clinical utility of serum procalcitonin(PCT) in the diagnosis of pulmonary infections in elderly populations due to different pathogens. Methods A retrospective review was conducted by collecting the clinical data and microbiological records of 166 aged patients(≥60) having pulmonary infections from January 2009 to December 2011, including bacterial pneumonia(92 cases, 50 Gram-negative bacteria and 42 Gram-positive bacteria), pulmonary candida infection(PC, 12 cases), active pulmonary tuberculosis infection(TB, 11 cases), Mycoplasma pneumoniae infection(MP, 31 cases), and viral pneumonia(20 cases). Furthermore, 12 healthy subjects who underwent the physical examination enrolled as the control group. The serum PCT levels and other biomarkers were determined. The non-parametric test was used to analyze the differences of PCT between the aforementioned groups while ROC curves to determine the best differentiating cut-off values. Results The PCT levels were significantly higher in all pulmonary infections but Mycoplasma pneumoniae than those in the control group(P<0.01). Moreover, the PCT levels in bacterial pneumonia and pulmonary candida infection indicated no significant difference(χ²=447.0, P=0.285), however, its levels in bacterial pneumonia and PC groups were significantly higher than those in active TB and MP infection groups(χ²=308.5, P=0.012). The changing trends of PCT concentrations in different groups were as follows: bacterial pneumonia≈PC>active TB>MP infection/viral infection≈control group. ROC curve indicated that at the cut-off values of 0.48 ng/mL and 0.10 ng/mL PCT could best differentiate bacterial pneumonia and PC from active TB and MP infection, respectively. Conclusion The serum PCT concentration, if at higher level, could be used as an effective means in differentiating pulmonary infections in the elderly populations, but if it was at slightly increased level, it might be caused by various microbiological pathogens that would reduce its clinical value and limit its utility.

Key words: pulmonary infection, procalcitonin, bacteremia