Evidence for the Platelet Specificity of β‐Thromboglobulin and Studies on its Plasma Concentration in Healthy Individuals

The concentration of normal human platelet beta-thromboglobulin (beta-TG) was measured in various washed organ samples by a radioimmunoassay. As only trace amounts were detected, beta-TG appears to be a platelet specific protein. Assay of beta-thromboglobulin in plasma samples from 180 normal individuals gave a range of 10--65 mg/ml. In the 10 subjects studied, plasma beta-TG concentration was related to platelet lifespan but not to turnover. The plasma beta-TG concentration rose with increasing age but did not correlate with the whole blood platelet count or the percentage of megathrombocytes. These results provide further substantial evidence that measurement of plasma beta-TG concentration is useful for assessing the participation of platelets in various disease processes.