• acute exacerbation;
  • diagnosis;
  • interstitial pneumonia;
  • procalcitonin;
  • prognosis


Background and objective

Acute exacerbation (AE) of interstitial pneumonia (IP) is defined as a life-threatening deterioration of IP without identifiable cause. We evaluated the diagnostic and prognostic role of serum procalcitonin (PCT) in AE-IP.


Twenty consecutive patients admitted for AE-IP between May 2010 and April 2012 were evaluated. Controls consisted of 13 consecutively admitted patients with acute respiratory distress syndrome (ARDS) due to bacterial pneumonia (BP) and 24 with bacterial pneumonia with stable IP (‘BP with IP’). Serum PCT was measured at baseline, at days 2, 4 and 8 in patients with AE-IP, and at baseline in controls.


Serum PCT levels in AE-IP were significantly lower than in BP-ARDS (mean ± standard deviation, 0.62 ± 1.30 vs 30.14 ± 22.76 ng/mL; P < 0.0001) or ‘BP with IP’ (mean ± standard deviation, 0.62 ± 1.30 vs 8.31 ± 14.83 ng/mL; P < 0.05). Thus, serum PCT discriminated well between AE-IP and BP-ARDS, or ‘BP with IP’ (area under the curve 0.99 and 0.85, respectively). However, there were no significant differences in serum PCT between 30-day survivors or non-survivors. Serum PCT tended to be reduced in both patient groups.


Serum PCT is a useful marker for discriminating between AE-IP and BP. However, serum PCT is not useful as a prognostic marker for survival.