The reversed ratio of 1-84 PTH (whole PTH)/intact PTH in a patient on hemodialysis associated with primary hyperparathyroidism.

Intact PTH measures not only 1-84 PTH, but also other fragments such as 7-84 PTH. Lately, a measurement of 1-84 PTH has been available as whole PTH assay and the ratio of whole PTH/intact PTH is considered to be between 0.5 and 0.7 in patients on hemodialysis. Therefore, intact PTH should be higher than whole PTH. We present a 57-year-old male with chronic renal failure on hemodialysis whose whole PTH was higher than intact PTH (the reversed ratio of whole PTH/intact PTH). He showed one enlarged parathyroid gland by an ultrasonic test, CT examination and RI subtraction study. After this gland was removed by surgery, the ratio of whole PTH/intact PTH normalized. The size of the resected gland was 22 x 15 x 11 mm. The histologic examination revealed adenoma. This indicates that, if patients with chronic renal failure showed the reversed ratio of whole PTH/intact PTH, the possibility that they could have primary hyperparathyroidism in addition to secondary hyperparathyroidism should be considered.