Intraoperative measurement of intact parathyroid hormone in renal hyperparathyroidism by an inexpensive routine assay

An individual approach to intraoperative parathyroid hormone measurement during total thyroidectomy

PURPOSE

Hypocalcemia is a common complication of thyroidectomy. Measurement of the intraoperative serum parathyroid hormone (PTH) levels became an established technique but it requires further improvements. We aimed to assess intraoperative PTH level testing results against the hypothesis that the PTH assay may be performed almost immediately after thyroid gland removal.

METHODS

A retrospective cohort study. During total thyroidectomy surgery, the patients had PTH levels measured at the cutting time and again immediately after the thyroid gland is removed. Post-operatively, serial total blood calcium levels were obtained twice daily and recorded.

RESULTS

Among 63 enrolled patients, 39 had multinodular goiter, 15 thyroid carcinoma, and nine had Graves' disease. The mean age was 59.8 ± 15.3 years, 43 females. The mean PTH level before surgery was 45.8 ± 22.0 pg/mL. Post-operatively, 11/63 patients developed hypocalcemia with serum calcium levels <8 mg/dL. Four patients with ≥50 % decrease in PTH concentration were normocalcemic a day after surgery and were discharged early. Four patients with ≥70 % PTH decrease were treated accordingly during prolonged hospitalization and did not suffer from permanent hypocalcemia. The cut-off value of 70 % decrease after the gland removal was able to predict postoperative hypocalcemia with a sensitivity of 100 %, specificity 82.9 %, PPV 60.0 % and NPV 100 %.

CONCLUSION

Measurements of intraoperative PTH may not be performed at fixed time intervals but after 1-2 min after removal of the thyroid gland. Defining those not at risk would allow the majority of patients to be waived from post-operative blood calcium testing and safely discharged early after surgery.

OUP accepted manuscript

Background

Several studies have reported on the use of intraoperative parathyroid hormone (ioPTH) measurements during parathyroidectomy (PTX) for renal hyperparathyroidism (rHPT), but there is no consensus on whether it is helpful and, if so, what protocol should be used. Therefore, the literature was systematically reviewed to assess a correlation between ioPTH and early postoperative parathyroid hormone (PTH) levels in patients undergoing PTX for rHPT, separately for those on dialysis and those with a functioning renal transplant.

Methods

A systematic literature search was performed in electronic databases. Quality assessment was performed using the Quality In Prognosis Studies tool. Mean ioPTH values were calculated at different time points and correlated to the postoperative PTH levels within 1 month. Fixed-effect and random-effects models were performed to assess the mean ioPTH levels at 10 or 20 min after resection (T10 and T20). Stratified analyses were performed for patients on dialysis and those with a functioning renal transplant.

Results

Of the 3087 records screened, 14 studies were included, including some 1177 patients; 1091 were on dialysis and 86 had a functioning kidney transplant. Risk of bias was moderate for most studies. For patients on dialysis, T10 and T20 mean ioPTH levels were 32.1 (95 per cent c.i. 24.3 to 39.9) pmol/l and 15.4 (95 per cent c.i. 7.8 to 22.9) pmol/l) in the random effects meta-analysis. Between individual studies, ioPTH ranged from 4.0–65.1 pmol/l at T10 and 8.6–25.7 pmol/l at T20. T10 and T20 ioPTH were 9.6 and 4.1 times the postoperative PTH—after T20 ioPTH stabilized in those on dialysis. In patients with a functioning renal transplant, ioPTH levels seemed to plateau after 10 min and measured 2.6 times the postoperative PTH.

Conclusion

There is a strong correlation between ioPTH and early postoperative PTH levels, indicating that ioPTH is potentially a useful instrument during PTX in patients with rHPT. For patients on dialysis, at T20 ioPTH levels have stabilized and are approximately four times the postoperative PTH. Therefore, it is recommended to use ioPTH 20 min after resection in patients on dialysis, which might be longer than necessary for those with a kidney transplant.

Intra-operative parathyroid hormone monitoring through central laboratory is accurate in renal secondary hyperparathyroidism

OBJECTIVE

The usefulness, the methods and the criteria of intra-operative monitoring of the parathyroid hormone (ioPTH) during parathyroidectomy (PTX) for renal secondary hyperparathyroidism (rSHPT) in patients on chronic hemodialysis remain still matter of debate. The present study aimed to evaluate the ability of a low cost central-laboratory second generation PTH assay to predict an incomplete resection of parathyroid glands (PTG).

METHODS

The ioPTH decay was determined In 42 consecutive patients undergoing PTX (15 subtotal and 27 total without auto-transplant of PTG) for rSHPT. The ioPTH monitoring included five samples: pre-intubation, post-manipulation of PTG and at 10, 20 and 30min post-PTG excision. The patients with PTH exceeding the normal value (65pg/ml) at the first postoperative week, 6 and 12months were classified as persistent rSHPT.

RESULTS

The concentrations of ioPTH declined significantly over time in patients who received total or subtotal PTX; however, no difference was found between the two types of PTX. Irrespective of the type of PTX and the number of PTG removed, combining the absolute and percentage of ioPTH decay at 30min after PTG excision, we found high sensitivity (100%), specificity (92%), negative predictive value (100%) and accuracy (93%) in predicting the persistence of rSHPT.

CONCLUSIONS

The monitoring of the ioPTH decline by a low cost central-laboratory second generation assay is extremely accurate in predicting the persistence of disease in patients on maintenance hemodialysis undergoing surgery for rSHPT.

Evaluation of intraoperative parathormone measurement for predicting successful surgery in patients undergoing subtotal/total parathyroidectomy due to secondary hyperparathyroidism

OBJECTIVES/BACKGROUND

The aim of this study is to investigate the predictive value of intraoperative parathormone measurement addressing successful surgical resection in patients with secondary hyperparathyroidism.

METHODS

The study included 42 consecutive patients operated on between May 2006 and July 2008. Patients were grouped according to successful surgery (Group 1, n = 36) and persistent postoperative hyperparathyroidism (Group 2, n = 6). Serum phosphorus (P), total calcium (tCa), ionized calcium (iCa), intact parathormone (iPTH), and alkaline phosphatase (ALP) were drawn preoperatively and intraoperatively upon 15 minutes after completion of resection (iPTH(15)). The rate of decrease of pith detected by iPTH(15) compared to preoperative values was calculated (iPTH(%)).

RESULTS

Preoperative P, tCa, iCa, iPTH, and ALP were comparable. Subtotal parathyroidectomy (sPx) (n = 27) and total parathyroidectomy with autotransplantation (tPx) (n = 15) were performed. Mean iPTH(15) value, iPTH(%) rates were 145.9 +/- 12.3 pg/mL, % 91.6 +/- 0.7, and 522.5 +/- 85.4 pg/mL, % 75.1 +/- 2.0 (P = ,001) in Groups 1 and 2, respectively. Mean serum tCa and iCa at POD#1 in Group 1 were 7.6 +/- 0.1 mg/dL, 0.910 +/- 0.4 mmol/L, and Group 2 were 8.3 +/- 0.3 mg/dL, 1.050 +/- 0.4 mmol/L (P < .05), respectively. ALP levels were similar.

CONCLUSION

iPTH(15) value and iPTH(%) rate accurately predicts the completeness of resection in secondary hyperparathyroidism. The rate of decrease in serum iPTH detected intraoperatively compared to preoperative baseline levels exceeding 90% in sPx, 95% in tPx, accurately predicts the success of surgery. Postoperative normocalcemia without calcium replacement would raise a suspicion about completeness of surgical resection.

Vitamin D status and its relation to muscle mass and muscle fat in young women

CONTEXT

Vitamin D insufficiency has now reached epidemic proportions and has been linked to increased body fat and decreased muscle strength. Whether vitamin D insufficiency is also related to adipose tissue infiltration in muscle is not known.

OBJECTIVE

The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD) and the degree of fat infiltration in muscle.

DESIGN

This was a cross-sectional study. OUTCOME MEASURES AND SUBJECTS: Measures were anthropometric measures, serum 25OHD radioimmunoassay values, and computed tomography (CT) values of fat, muscle mass, and percent muscle fat in 90 postpubertal females, aged 16-22 yr, residing in California.

RESULTS

Approximately 59% of subjects were 25OHD insufficient (< or = 29 ng/ml), of which 24% were deficient (< or = 20 ng/ml), whereas 41% were sufficient (> or = 30 ng/ml). A strong negative relationship was present between serum 25OHD and CT measures of percent muscle fat (r = -0.37; P < 0.001). In contrast, no relationship was observed between circulating 25OHD concentrations and CT measures of thigh muscle area (r = 0.16; P = 0.14). Multiple regression analysis indicated that the relation between 25OHD and muscle adiposity was independent of body mass or CT measures of sc and visceral fat. Percent muscle fat was significantly lower in women with normal serum 25OHD concentrations than in women with insufficient levels and deficient levels (3.15 +/- 1.4 vs. 3.90 +/- 1.9; P = 0.038).

CONCLUSIONS

We found that vitamin D insufficiency is associated with increased fat infiltration in muscle in healthy young women.

Diagnosis and management of pediatric endocrine neoplasms

PURPOSE OF REVIEW

To guide the clinician in the diagnostic evaluation of endocrine neoplasms, to distinguish between benign and malignant and determine when surgical referral is indicated.

RECENT FINDINGS

Thyroid nodules are uncommon but malignant in as many as 27% of patients. Fine needle aspiration should be considered in adolescents, in which accuracy is as high as 90%; surgical resection should be undertaken in all preadolescents (<13 years) with a thyroid nodule. Prognosis for most primary thyroid malignancies is favorable. Primary hyperparathyroidism is rare and due to an adenoma in up to 70% of patients. Surgical resection carries a cure rate of 95% with the use of intraoperative parathyroid hormone assays. Adrenal neoplasms cover a wide spectrum of disorder. They are functional in 95% of patients and require a thorough diagnostic evaluation prior to surgical resection. Malignant lesions of the adrenal gland carry a poor prognosis when complete surgical resection cannot be achieved. Carcinoids are rare neuroendocrine neoplasms, primarily of the appendix, associated with carcinoid syndrome in 10% of patients. The indolent course warrants aggressive surgical control.

SUMMARY

Endocrine neoplasms are unusual in the pediatric population. Their presence should raise concern about a multiple endocrine neoplasia syndrome and appropriate diagnostic and endocrine work-up. Most neoplasms will require surgical resection.

Vitamin D status and its relationship to body fat, final height, and peak bone mass in young women

CONTEXT

Vitamin D insufficiency has now reached epidemic proportions and has been linked to low bone mineral density, increased risk of fracture, and obesity in adults. However, this relationship has not been well characterized in young adults.

OBJECTIVE

The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD), anthropometric measures, body fat (BF), and bone structure at the time of peak bone mass.

DESIGN

This was a cross-sectional study. OUTCOME MEASURES AND SUBJECTS: Anthropometric measures, serum 25OHD radioimmunoassay values, and computed tomography and dual-energy x-ray absorptiometry values of BF and bone structure in 90 postpubertal females, aged 16-22 yr, residing in California were measured.

RESULTS

Approximately 59% of subjects were 25OHD insufficient (<or=29 ng/ml), and 41% were sufficient (>or=30 ng/ml). Strong negative relationships were present between serum 25OHD and computed tomography measures of visceral and sc fat and dual-energy x-ray absorptiometry values of BF. In addition, weight, body mass, and imaging measures of adiposity at all sites were significantly lower in women with normal serum 25OHD concentrations than women with insufficient levels. In contrast, no relationship was observed between circulating 25OHD concentrations and measures of bone mineral density at any site. Unexpectedly, there was a positive correlation between 25OHD levels and height.

CONCLUSIONS

We found that vitamin D insufficiency is associated with increased BF and decreased height but not changes in peak bone mass.

The role of quick bio-intact PTH(1-84) assay during parathyroidectomy for secondary hyperparathyroidism

OBJECTIVE

The role of the quick PTH assay in surgery for secondary HPT is unclear because of overestimation of intact PTH(1-84) values due to the cross-reactivity of currently available first-generation PTH assays with non-PTH(1-84) fragments that accumulate in renal failure. In this study, we used a second-generation quick PTH immunometric assay that are claimed to detect the biologically active PTH(1-84) molecule with no cross-reactivity with PTH fragments to investigate the potential utility of the assay during parathyroidectomy for secondary HPT.

MATERIAL AND METHODS

The study was performed on 18 patients (12 women, 6 men) between October 2004 and March 2005. EDTA serum samples were drawn via a peripheral venous catheter after induction of anesthesia (basal), and at 5, 10, and 30 min after excision of diseased parathyroid glands. Serum active PTH(1-84) was measured by the quick Bio-Intact PTH(1-84) assay, which is a two-site chemiluminometric assay.

RESULTS

At 30 min the quick Bio-PTH(1-84) level of 16 patients was under 45 pg/mL. Four parathyroid glands were removed macroscopically from 12 of the 16 patients, and three glands were removed from the other four patients. All patients were cured of their HPT. Four enlarged parathyroid glands were removed from a patient whose Bio-Intact PTH(1-84) at 30 min had not fallen below 45 pg/mL, and no other glands were found by further exploration. At the 6 mo follow-up examination, the first-generation intact PTH level of this patient was over 45 pg/mL, but several diagnostic imaging methods did not reveal any enlarged parathyroid glands. Three enlarged parathyroid glands from the other patient, and exploration led to the identification of an ectopic parathyroid gland at the carotid bifurcation.

CONCLUSIONS

The results of this prospective study show that quick Bio-Intact PTH(1-84) monitoring is a valuable new tool for use in the surgical treatment of secondary HPT. An intraoperative, quick Bio-Intact PTH(1-84) assay will be of value for the adequate prediction of surgical cure.

Impact of intraoperative parathyroid hormone levels on surgical results in patients with renal hyperparathyroidism

The aim of our study was to evaluate the impact of intraoperative parathyroid hormone (PTH) measurement on surgical results in patients with renal hyperparathyroidism (HPT). From December 1999 to February 2004, a series of 95 consecutive patients underwent total parathyroidectomy and intraoperative PTH measurement for renal HPT. Intraoperative PTH was measured before and 15 minutes after parathyroidectomy with the Immulite DPC assay for intact PTH. The median PTH levels before surgery were 133.0 pmol/L, which declined to 5.9 pmol/L at the end of the operation. At follow-up, 91 of 95 (96%) patients presented with normal calcium levels. Persistent renal HPT was seen in three patients, and recurrent HPT was diagnosed in another. In 99% of the patients the intraoperative PTH levels declined more than 50% and in 73% the PTH decay was more than 90%. In 64% of the patients PTH levels dropped into the normal range (< 7.6 pmol/L). Altogether, 97% of the patients with an intraoperative PTH decrease of more than 90% presented with normal PTH levels postoperatively (p = 0.0237), as did all of the patients whose intraoperative PTH dropped into the normal range (p = 0.0432). Intraoperative PTH measurement with a decrease in intraoperative PTH of at least 90% is highly predictive of successful parathyroidectomy and normalization of postoperative calcium and PTH levels.

Quick PTH assay cannot predict incomplete parathyroidectomy in patients with renal hyperparathyroidism

BACKGROUND

Contradictory reports on the value of intraoperative quick parathyroid hormone (PTH) monitoring in renal hyperparathyroidism have been published.

METHODS

Thirty-five consecutive patients underwent total parathyroidectomy, central neck dissection, bilateral thymectomy, and immediate autotransplantation. PTH levels were measured by PTH assay at induction of anesthesia (baseline level) and in 5-minute intervals after excision of the last parathyroid gland. Parathyroidectomy was considered "total" in patients with PTH levels <10 pg/mL (subgroup 1), "subtotal" between 10 and 65 pg/mL (subgroup 2) and "insufficient" at >65 pg/mL (subgroup 3) within the first postoperative week.

RESULTS

Fifteen minutes after excision of the last gland, PTH levels dropped to 19.4 +/- 15.7% (subgroup 1), 14.9 +/- 5.9% (subgroup 2), and 18 +/- 6.7% (subgroup 3) from baseline among 22 patients on hemodialysis, to 22.1 +/- 18.7% and 17.5% in 9 patients (subgroups 1 and 2) after successful kidney transplantation, and to 10.7% and 17.5% (subgroup 1) and 12.8% and 31.4% (subgroup 2) in 4 patients with reduced renal function after kidney transplantation.

CONCLUSIONS

Currently available QPTH assays are not useful to predict insufficient resection of hyperfunctioning parathyroid tissue.

Predictive value of intact parathyroid hormone measurement during surgery for renal hyperparathyroidism

BACKGROUND AND AIMS

In contrast to that in patients with primary hyperparathyroidism, the value of intraoperative intact parathyroid hormone (iPTH) measurement is still unclear in patients with renal hyperparathyroidism and was, therefore, evaluated in a large cohort of patients.

PATIENTS

Intraoperative iPTH measurement was performed in 153 patients with renal hyperparathyroidism (129 with terminal renal failure and 24 with functioning kidney graft). Subtotal and total parathyroidectomy were performed in 123 and 13 patients, respectively, during initial surgery. In patients with recurrent disease (17), the respective hyperfunctioning tissue was removed. Intraoperative blood samples were obtained by puncture of the internal jugular vein before preparation of the parathyroids (PTH0) and 15 min after parathyroidectomy (PTH15). iPTH was measured with the Elecsys 2010 system. Postoperative iPTH levels (PTH(post)) were determined at postoperative days 1 to 3 and at week 2. Patients were arbitrarily divided in four groups according to the postoperative iPTH values: 0-25 pg/ml (group 1), 26-65 pg/ml (group 2), 66-150 pg/ml (group 3) and more than 150 pg/ml (group 4).

RESULTS

The mean PTH0 value was 869+/-57 pg/ml, which decreased to 167+/-15 pg/ml at PTH15. The mean relative PTH15 value was 21.6+/-1.7%. Postoperatively, iPTH decreased to 42+/-9 pg/ml. The postoperative iPTH value of the 129 patients with terminal renal failure was 25 pg/ml or less in 99 patients, 26-65 pg/ml in 11 patients, 66-150 pg/ml in eight patients and higher than 150 pg/ml in 11 patients. Two successive criteria of iPTH decrease were used: first, a PTH15 of < or =150 pg/ml or, second, a relative PTH15 of < or =30% less was used. Fifteen patients did not fulfil both criteria. In 13 of them (86.7%) iPTH(post) was higher than 65 pg (true failure to decline). Of 114 patients who fulfilled the criteria, 108 (94.7%) had normal postoperative iPTH values (true decline). Absolute PTH15 values of less than 150 pg/ml predicted normal postoperative iPTH levels in 77 of 78 patients.

CONCLUSION

A PTH15 value of 150 pg/ml or less predicts operative success in patients with renal failure in 98.7% of cases, independently of the relative decay. In contrast, if the relative PTH15 is higher than 30%, high postoperative PTH values are predicted with a probability of 86.7%. Although there remain some borderline cases, intraoperative iPTH measurement is accurate and also can be useful in patients with renal hyperparathyroidism.

A randomised study on a new cost-effective algorithm of quick intraoperative intact parathyroid hormone assay in secondary hyperparathyroidism

BACKGROUND AND AIMS

The use of intraoperative intact parathyroid hormone (iPTH) assay in secondary renal hyperparathyroidism (SHP) has been limited by the relatively low cost effectiveness of the assay in improving the success rate for primary bilateral neck exploration. The study aimed at determining, in a prospective, randomised trial, the cost effectiveness and impact of the routine employment of a "six-sample" versus "two-sample" algorithm of the intraoperative iPTH assay during surgery for SHP on intraoperative decision making and surgical success rate.

PATIENTS AND METHODS

One hundred and two consecutive patients with severe SHP and qualified for subtotal parathyroidectomy were randomly allocated to two equal-sized groups: group A, in which the intraoperative iPTH serum level was determined in six consecutive samples: preoperative, pre-excision, 5, 10, 20 and 60 min, and group B, in which the intraoperative iPTH serum level was determined twice only: preoperatively and 10 min. The STAT intraoperative intact-PTH immunoassay was employed. In group B, in patients with serum iPTH decrease lower than 60% of the baseline at 10 min, an additional measurement was performed at 20-min post-excision. If a decrease of 80% or more of the baseline was not obtained, the exploration was extended in search of remaining hyperfunctioning parathyroid tissue.

RESULTS

The surgical success rate was 96.1% and 98.0% (in group A and B, respectively). The impact of the intraoperative iPTH assay on surgical decision making was demonstrated in 13.7% and 15.7% (in group A and B, respectively). The assay was helpful in identifying patients with supranumerary hyperfunctioning parathyroid tissue (5.9% vs 7.8% in group A and B, respectively), patients with fewer than four parathyroid glands (3.9% vs 5.9% in group A and B, respectively) and patients with remaining hyperfunctioning parathyroid tissue suspected to be located within the mediastinum in cases of negative bilateral neck exploration who benefit from transcervical thymectomy. The diagnostic accuracy of the intraoperative iPTH assay was 100% in both groups. The accuracy of two-sample algorithm increased from 96% to 100% if an additional serum iPTH determination was performed in borderline cases with an iPTH drop lower than 60% of the baseline at 10 min. The cost-effectiveness analysis showed significant savings in group B, equal to Euro 87.6 per patient, with the unchanged diagnostic accuracy of the two-sample algorithm.

CONCLUSIONS

The intraoperative iPTH assay in patients operated on for secondary hyperparathyroidism offers support in surgical decision making in the majority of patients, allowing for correct identification of patients with supranumerary ectopic hyperfunctioning parathyroid glands, and in patients with fewer than four parathyroid glands. It also correctly identifies patients who do not benefit from blind thymectomy. The two-sample algorithm, extended to include three determinations in selected cases, has the same 100% diagnostic accuracy as the six-sample algorithm, the former being a much more cost-effective procedure.

Measurement of parathyroid hormone and application of parathyroid hormone in intraoperative monitoring

There has been a clear progression in assays for the analysis of PTH and its clinical applications. This includes the innovative use of PTH as a point-of-care assay as an intraoperative measure of the success of parathyroid surgery. The rapid PTH assay has served as a model for the development of other rapid hormone assays, such as for adrenocorticotropic hormone,although the clinical usefulness of these other applications is less well established. Knowledge of the circulating forms of PTH continues to progress. Information about the biologic and immunologic activities of these forms will aid in the interpretation and clinical use of current assays and in the development of new assays with improved specificities. The clinical laboratory will continue to play a vital role in providing testing and support for this important mediator of mineral metabolism.

Rapid intraoperative immunoassay of parathyroid hormone and other hormones: a new paradigm for point-of-care testing

BACKGROUND

The first description of the use of a rapid assay for the measurement of intact parathyroid hormone (PTH) in patients undergoing parathyroidectomy for hyperparathyroidism was reported in 1988. Subsequent improvements in the analytical performance of the rapid intraoperative PTH assay allowed the establishment of its clinical utility in the surgical management of hyperparathyroidism. These modifications also allowed the assay to be performed in or near the operating suite.

METHODS

We searched MEDLINE, using the following key words: intraoperative, rapid, quick, parathyroid hormone, hormone, and immunoassay. Relevant articles that focused on the analytical aspects and clinical utility of rapid intraoperative hormone immunoassays were selected for this review.

CONTENT

On the basis of the positive impact that the rapid intraoperative PTH test has had on both patient outcomes and cost savings, other rapid intraoperative hormone immunoassays for the diagnosis and/or treatment of other endocrine-hormone-secreting tumors have been developed. These hormones share certain characteristics that make them suitable for use as rapid intraoperative tests, i.e., short analyte half-life and/or large analyte concentration gradient, rapid analysis time, and positive clinical utility. Initial studies with cortisol, gastrin, insulin, adrenocorticotropic hormone, and testosterone have shown promising results in preoperative localization studies and/or for assessing the effectiveness of tumor resection during surgery.

CONCLUSION

The emergence of these rapid intraoperative immunoassays indicates that this test format is likely to provide future opportunities to improve patient care by advances in clinical laboratory testing.

Intraoperative testing for parathyroid hormone: a comprehensive review of the use of the assay and the relevant literature

OBJECTIVE

The rapid intraoperative parathyroid hormone assay is transforming the parathyroidectomy procedure. We present a review of the literature on the use of the assay as an adjunct to surgery. To our knowledge, this is the first review of the literature to encompass and compare all known primary studies of this assay in parathyroidectomy patients.

DATA SOURCES

Articles were collected by searching MEDLINE databases using relevant terminology. The references of these articles were reviewed for additional studies. Supplementary articles pertinent to the parathyroidectomy procedure, preoperative parathyroid localization studies, and intraoperative parathyroid hormone assay development also were examined.

STUDY SELECTION AND DATA EXTRACTION

One hundred sixty-five references were analyzed and categorized separately into groups.

DATA SYNTHESIS

The primary studies of intraoperative data on patients undergoing parathyroidectomy were compared when possible. Studies were analyzed by type of assay used, where performed, turnaround time, and efficiency of use. Reviews of the types of parathyroid surgery and preoperative localization were included for educational purposes.Conclusions.-The intraoperative parathyroid hormone assay is a useful adjunct to preoperative imaging and parathyroid surgery because of its unique ability to detect an occult residuum of hyperfunctioning parathyroid tissue. Use of this assay will obviate the need for frozen section in most routine cases. The test facilitates minimally invasive parathyroidectomy for single parathyroid adenomas, which, in turn, improves cost-effectiveness and cosmetic outcome. Its use in patients with known preoperative multiglandular disease is promising but requires further study.

Intraoperative parathyroid hormone testing: survey of testing program characteristics

OBJECTIVE

To examine the number and testing characteristics of laboratories that offer intraoperative testing of intact parathyroid hormone (PTH).

DESIGN

Laboratories (n = 355) that participated in 2001 in PTH proficiency testing with the College of American Pathologists Special Ligand Survey were surveyed about intraoperative PTH testing.

RESULTS

Of the 320 laboratories that responded to the survey, 92 performed intraoperative PTH testing. Testing practices were divided nearly equally among laboratories that performed intraoperative PTH testing for all parathyroidectomies (40%), most but not all cases (31%), and less than half of cases (30%). Testing frequency usually was low, with about two thirds of laboratories reporting 5 or fewer cases per month. A surprising finding was that, although intraoperative PTH testing originally became widely practiced as a point-of-care test, 71% of laboratories performed testing in a central laboratory, 6% in satellite laboratories, and only 23% in operating suites. A survey of methods showed that 33% used the manual QuiCk-Intraoperative test, 47% used the automated Immulite Turbo intact PTH assay, and 20% used other methods.

CONCLUSIONS

Intraoperative testing of intact PTH, although relatively new, has come into widespread practice during parathyroid surgery. Service delivery has evolved from a point-of-care model toward a central laboratory model, with this test serving as an illustrative example of factors that affect the balance between point-of-care and laboratory testing.