The correlation of routine cytology with the contents of carcinoembryonic antigen and alpha-fetoprotein in pleural and peritoneal effusions.

The levels of carcinoembryonic antigen (CEA) and of alpha-fetoprotein (AFP) were determined with radioimmunoassay in 63 samples of either pleural or peritoneal effusions. All samples were collected from 53 patients suspected for malignancy and were also studied with the routine cytological techniques. Elevated levels of CEA (above 20 ng/ml) were found in 14 out of 29 cytologically positive samples, in none of 6 cytologically suspected and of 14 cytologically negative samples. The highest levels of CEA (above 1,000 ng/ml) were found in samples from patients with gastrointestinal carcinomas, while negative results were most often found in lymphoreticular and ovarian malignancies. Elevated levels of AFP (above 5 ng/ml) were found in 9 samples (5 cytologically positive and 4 negative). Five of these exudates were negative for CEA. Positive results of AFP were most frequently found in samples derived from patients with secondary or primary liver tumours. The highest levels of AFP (6 and 30 ng/ml), were determined in samples of two hepatoma patients. The combined cytological and radioimmunological studies suggested malignancy in 52 out of 63 samples while cytology alone detected either neoplastic or suspected cells in 35 samples only.