[The clinical significance of sialic acid in the serum in benign and malignant disease].

The concentrations of sialic acid in the serum of patients with benign and malignant diseases were determined and the criteria of diagnostic validity (sensitivity, specificity, efficiency, likelihood ratio, predictive values) were calculated. The concentrations of sialic acid in sera of patients with benign diseases (median 0.826 g/l, 5. percentile 0.62 g/l, 95. percentile 1.27 g/l, p less than 0.001) and malignant diseases (median 0.90 g/l, 5. percentile 0.67 g/l, 95. percentile 1.48 g/l, p less than 0.001) were significantly higher than those in a population of healthy persons (median 0.62 g/l, 5. percentile 0.52 g/l, 95. percentile 0.78 g/l). In malignant diseases, the serum sialic acid concentrations are significantly higher (p less than 0.005) than those in benign diseases. In the group of benign diseases marked increases were seen in patients with rheumatoid arthritis and collagenoses (median 1.03 g/l) and infectious-inflammatory diseases (median 0.97 g/l). In the group of malignant diseases increases were seen in cases of gastrointestinal carcinomas (median 1.1 g/l), bladder tumours (n = 2, 1.12 g/l, 1.08 g/l) and carcinoma of the uterus (median 1.0 g/l). The sensitivity at a decision limit of 0.78 g/l for benign diseases is 0.68, for malignant diseases 0.83 and for both categories 0.71. The specificity for benign diseases is 0.94, for malignant diseases 0.32, for both categories 0.94. For benign diseases, the positive predictive values at a decision limit of 0.78 g/l are 0.55 and 0.72 (given prevalences 0.1 and 0.2, respectively); for malignant diseases, 0.11 and 0.23 (prevalences 0.1 and 0.2); for both categories 0.77 and 0.88 (prevalences of 0.1 and 0.2).(ABSTRACT TRUNCATED AT 250 WORDS)