7-84 parathyroid hormone fragments are proportionally increased with the severity of uremic hyperparathyroidism.
OBJECTIVE
Recent progress in PTH assay has revealed that the intact PTH assay kit in current use does not differentiate between the truncated 7-84 PTH molecule and the 1-84 PTH molecule. In our series, we examined the effectiveness of a new PTH assay as a noninvasive method of evaluating severity of uremic hyperparathyroidism.


METHODS
Two hundred and seventy hemodialysis (HD) patients recruited from three HD centers were included and divided into subgroups according to the conventional iPTH assay results. Pre-dialysis blood samples were collected and subjected to two different PTH assays: "intact" PTH assay (iPTH) and "whole" PTH (wPTH) assay. Two biochemical markers of bone remodeling were also examined.


RESULTS
In all cases, PTH levels determined by the wPTH assay were in the average 32.3% lower than those determined by the iPTH assay. The difference of the results of the two PTH assay methods, which indicated the portion of 7-84 PTH fragments of the total PTH molecules measured with the iPTH assay, was gradually increased while the severity of uremic hyperparathyroidism increased. Biochemical markers of bone formation/resorption showed a similar change.


CONCLUSIONS
The portion of the 7-84 PTH fragments and markers of increased bone turnover increased in proportion to the severity of uremic hyperparathyroidism. This finding disproves the hypothetical role of 7-84 PTH fragments alone as the noninvasive marker of low-turnover bone disease in HD patients.
Chang
J M
JM
Department of Nephrology, Kaohsiung Medical University, Taiwan.
Lin
S P
SP
Kuo
H T
HT
Tsai
J C
JC
Tomino
Y
Y
Lai
Y H
YH
Chen
H C
HC
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000175:diagnosis* / Q000209:etiology; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000175:diagnosis* / Q000209:etiology; D007676:Kidney Failure, Chronic / Q000150:complications / Q000175:diagnosis / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000378:metabolism* / Q000652:urine; D011379:Prognosis; D011446:Prospective Studies; D011863:Radioimmunoassay; D012016:Reference Values; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012737:Sex Factors
D015415:Biomarkers; D010281:Parathyroid Hormone