Usefulness of Carcinoembryonic Antigen Determination in Bronchoalveolar Lavage Fluid (9)In the present study, although CEA levels in BAL fluid and serum were higher in smokers than in nonsmokers, differences were not significant. Likewise, no correlation was found between cigarette consumption expressed in pack/years and CEA assay. Patients with pneumonia also had elevated CEA levels in both BAL fluid and serum, but differences with respect to healthy individuals were not significant.
In lung cancer, previous studies have shown that CEA concentration was much higher in BAL fluid than in serum. Similar results were obtained in our study. CEA concentrations were also significantly higher in BAL fluid of patients with lung cancer than in pneumonia patients or in healthy individuals. However, in serum we could not find any significant differences between patients with pneumonia and lung cancer. Differences were significant, however, when comparing with healthy individuals, smokers, and nonsmokers.

These results indicate that CEA determinations only in BAL fluid but not in serum could be of value in discerning between lung cancer patients presenting with postobstructive pneumonitis and individuals with pneumonia. When we considered the diagnostic value of CEA in serum of patients with a lung peripheral mass, we found that the sensitivity and the specificity were very low (55 percent and 91 percent, respectively), similar to reports by other authors. In BAL fluid, however, the sensitivity and the specificity were higher (77 percent and 94 percent, respectively). Positive and negative predictive value in BAL improved, 77 percent and 94 percent, respectively.
Although the diagnostic value of CEA in BAL fluid is higher than in serum, still 23 percent of patients with lung cancer will have a false negative result.