We found no correlation among age, cigarette consumption, and CEA levels in any of the groups.
Patients with cancer had CEA lavage fluid levels significantly higher than patients with pneumonia, in absolute values (p<0.005) or referred to albumin concentration (p<0.05). Similarly, patients with cancer had significantly higher mean CEA levels in serum (p<0.05) and iavage fluid (p<0.005) than healthy subjects, smokers, and nonsmokers. In serum, however, CEA assay cannot discern between cancer and pneumonia patients (p = 0.06).
On the other hand, there were no significant differences in CEA levels of either serum or lavage fluid between patients with pneumonia and healthy subjects. Therefore, we joined these two groups together as the control group. The diagnostic value of the CEA assay among patients with cancer was analyzed in terms of sensitivity, specificity, and predictive value, after selecting the best cutting point. Results can be seen in Table 3. Using 1,000 ng of CEA per milligram of albumin as the cutting point in BAL fluid, the sensitivity was 77 percent and the specificity was 94 percent. With 5 ng/ ml for serum CEA, they were 55 percent and 91 percent, respectively. Positive and negative predictive values were 77 percent and 94 percent in BAL fluid, while in serum they were 62 percent and 89 percent.

Table 3—Diagnostic Value of CEA in BAL and Serum of Patients with Peripheral Lung Cancer

CEA (S), CEA (L), CEA (SandL), TB and CEA (L), Cyt and CEA (L), TB and Cyt and CEA (L),
% % % % % %
Sensitivity 55 77 88 88 77 88
Specificity 91 94 88 94 94 94
Positive PV 62 77 66 80 78 80
Negative PV 89 94 96 97 94 97