[Calcitonin values in normal human blood].

Since 1969 when Clark, et al. established the radioimmunoassay for human calcitonin, a number of reports have been published. However, the normal value of calcitonin has never been definitely ascertained. The calcitonin value in the blood of 256 normal individuals was measured by radioimmunoassay using the Dai-ichi Calcitonin Kit, and the X-ray findings in 133 of this population were studied. The calcitonin value was found to range from less than 10 to 249 (average 49.0) pg/ml. In terms of age, it was shown to be highest in the third decade and tended to decrease from the fourth decade on. In terms of sex, it was higher in females in the second, sixth and seventh decades but higher in males in the third--the fifth decades. There was no relationship between the degree of bone atrophy and the calcitonin value in the blood.