medwireNews: Serum procalcitonin (PCT) is a useful marker for distinguishing between acute exacerbation of interstitial pneumonia (AE-IP) and bacterial pneumonia, say researchers.

However, it is not useful as a prognostic marker for survival, add Kazuma Nagata (Kobe City Medical Center, Chuo-Ku, Japan) and team in Respirology.

The analysis included 20 consecutive patients who were admitted for AE-IP between 2010 and 2012; as well as 13 consecutively admitted patients with acute respiratory distress syndrome due to bacterial pneumonia (BP-ARDS) and 24 patients with bacterial pneumonia and stable interstitial pneumonia (BP with IP), who served as controls.

Mean serum PCT levels in patients with AE-IP were significantly lower than in BP-ARDS patients, at 0.62 ng/mL versus 30.14 ng/mL. Mean serum PCT was also significantly lower in AE-IP patients than in those with BP with IP, at 0.62 ng/mL versus 8.31 ng/mL.

These findings imply that serum PCT discriminated well between patients with AE-IP and those with BP-ARDS or BP with IP, say the authors.

However, they point out, there was no significant difference in serum PCT between 30-day survivors and nonsurvivors, with a tendency toward low levels in both groups. This demonstrates that serum PCT has no value as a prognostic marker for survival, they explain.

"As we demonstrated, serum PCT was high in almost all of the patients in the control groups, whereas it was within normal limits or only slightly elevated in AE-IP," write Nagata and team.

"These results document that the serum PCT level is useful for identifying bacterial infection in interstitial patients with acute respiratory failure."

Nagata and team conclude: "Ascertaining serum PCT levels may help physicians to decide on the need for corticosteroids and antibiotic treatment. Our results also have relevance for treating AE-IP patients thought to have a superimposed bacterial infection."

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