Accuracy of PTH assay and corrected calcium in early prediction of hypoparathyroidism after thyroid surgery.
OBJECTIVE
To evaluate the accuracy of the intraoperative parathyroid hormone (ioPTH) and 6-hour PTH (6hPTH) assay in predicting transient hypoparathyroidism after thyroidectomy.


METHODS
A nonrandomized prospective study was conducted on patients undergoing thyroid surgery.


METHODS
Of 138 patients undergoing thyroid surgery, intraoperative PTH was measured 10 minutes after gland removal. Serum calcium, magnesium, inorganic phosphorus, albumin, and PTH levels were assayed 6 and 16 hours after surgery and daily until patient discharge.


RESULTS
The development of postoperative hypocalcemia was associated with low ioPTH (P < 0.0001) and 6hPTH (P < 0.0001) values, and the decline of PTH from baseline (P < 0.0001). The cutoff for percentage decline of ioPTH and 6hPTH (55.7% and 379%, respectively) was more accurate than an absolute value. Accuracy, and positive and negative predictive values were 88 percent, 63 percent, and 100 percent for ioPTH and 75 percent, 46 percent, and 100 percent for 6hPTH, respectively.


CONCLUSIONS
With the use of ioPTH decline in association with 16-hour corrected calcium, it is possible to distinguish early normocalcemic patients from hypocalcemic ones in most cases.
Cavicchi
Ottavio
O
ENT Department, S Orsola-Malpighi Hospital, Bologna University, Bologna, Italy. ocavicchi@libero.it
Piccin
Ottavio
O
Caliceti
Umberto
U
Fernandez
Ignacio Javier
IJ
Bordonaro
Carla
C
Saggese
Domenico
D
Ceroni
Alberto Rinaldi
AR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D007011:Hypoparathyroidism / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011183:Postoperative Complications / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D013965:Thyroidectomy; D013997:Time Factors
D010281:Parathyroid Hormone; D002118:Calcium