Serum Procalcitonin Evaluated as Interstitial Pneumonia Diagnostic Marker

Serum PCT was measured at baseline, day two, four, and eight in patients with AE-IP, and at baseline in controls. The controls consisted of 13 consecutively admitted patients with Acute Respiratory Distress Syndrome due to bacterial pneumonia (BP-ARDS), and 24 with bacterial pneumonia with stable interstitial pneumonia (BP with IP).

Serum PCT levels in AE-IP were significantly lower with a mean of 0.62 ng/mL than in BP-ARDS patients whose mean was 30.14 ng/mL or for patients BP with IP, where the mean was 8.31 ng/mL. The results suggest that serum PCT discriminated well between AE-IP and BP-ARDS or BP with IP. However, there were no significant differences in serum PCT between 30-day survivors or nonsurvivors as serum PCT tended to be reduced in both patient groups.

The level of procalcitonin in the blood stream of healthy individuals is below the limit of detection of 10 pg/mL in clinical assays. The level of procalcitonin rises in a response to a proinflammatory stimulus, especially of bacterial origin, where it is produced mainly by the cells of the lung and the intestine. It does not rise significantly with viral or noninfectious inflammations. The authors concluded that serum PCT is a useful marker for discriminating between AE-IP and bacterial pneumonia. However, serum PCT is not useful as a prognostic marker for survival. The study was published on December 5, 2012, in the journal Respirology.

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