Parathyroid Levels Research Articles

Evaluation of serum calcium and serum parathyroid levels in post-menopausal women with and without oral dryness.

The primary objective of this study was to estimate and secondary objective was to compare the serum calcium levels and serum parathyroid hormone (PTH) levels in post-menopausal women with and without oral dryness (OD). A case-control study was carried out on 80 selected post-menopausal women. Salivary flow was assessed by flow rate; serum calcium concentrations were assessed through Semi Autoanalyzer by Arsenazo III reaction. The serum PTH concentration was measured by the enzyme-linked immunosorbent assay. Severity of OD was assessed by a questionnaire through which the xerostomia inventory (XI) score could be measured. Statistical analysis of Student's t-test, Mann-Whitney test and Pearson's correlation was used. There was a significant difference in mean values of both serum PTH concentration and XI score in post-menopausal women with/without OD (p < 0.001). No statistically significant difference (p = 0.354) was found in salivary flow rate and serum calcium levels in post-menopausal women in both groups. A positive correlation was found between the serum PTH and XI score in both case and control groups (p < 0.05). Severity of oral dryness in post-menopausal women is associated with the high levels of serum PTH. However, the correlation of severity of OD with serum calcium could not be established.

“SUBCLINICAL RICKETS IN HAZARIAN STUDENTS”

Objective: The study on sub clinical rickets is unique in the sense that it has not been preplanned conducted anywhere especially in Pakistan. The objective of present study was to explore the prevalence, gender and geographical distribution of sub clinical rickets and their related factors among school students.Methods: Out of total participants, 189(90%) students were finally included in the study from rural, urban and suburban high schools of Hazara Division, KPK. The age of boys and girls students was 11 years to 16 years. Anthropometrics data along with daily intakes of meal and availability of sun shine was noted on record form. Sub clinical cases were diagnosed with abnormal biochemical findings without physical indications of rickets.Results: Sub clinical rickets was found in 51(27%) students, out of which 15(8%) were boys and 36(19%) girls. Geographically, 26 cases of sub clinical rickets were from rural schools, 16 of urban and 09 found in suburban school. All sub clinical cases had serum level of sunshine vitamin D in between ≥18nmol/l to ≤39 nmol/l, but none of them had parathyroid level increased from upper normal range. Estimated quantities of vitamin D, calcium and phosphorus in daily intakes meal of boy’s and girl’s student were almost same and found less than recommended amount.Conclusion: Sub clinical rickets is camouflagic rickets among Hazarian school students, especially in girl gender. The major cause contributed to this problem is lack of synergistic effect of Sunshine Vitamin D.doi: http://dx.doi.org/10.12669/pjms.304.4518How to cite this:Shah TH, Hassan M, Siddiqui TS. Subclinical Rickets. Pak J Med Sci 2014;30(4):854-857. doi: http://dx.doi.org/10.12669/pjms.304.4518This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

G259(P) Hypercalcaemia- a herald sign of leukaemia in children

We present an interesting case of a 12 year old boy who presented with features of renal failure and hypercalcaemia who was later diagnosed with acute lymphoblastic leukaemia.This young man...

Letrozole Induced Hypercalcemia in a Patient with Breast Cancer

Hypersecretion of PTHrP is a relatively common cause of malignancy-related hypercalcemia. However, there is only one case report of letrozole induced hypercalcemia. A 52-year-old female patient was referred to our clinic because of the recent discovery of hypercalcemia (11.0 mg/dL). The patient had a history of left breast carcinoma. She had started a course of letrozole (aromatase inhibitor; 2.5 mg dose/day) ten months earlier. Patient's parathyroid hormone-related protein levels were normal and a bone scintigram revealed no evidence of skeletal metastasis. Other potential causes of high calcium levels were ruled out. We recognized that, when letrozole was taken at one dose daily (2.5 mg), she had recurrent hypercalcemia. Our experience suggests that letrozole may precipitate hypercalcemia in a patient with breast cancer.

Tumor-induced osteomalacia—a diagnostic dilemma for an orthopedic surgeon

Tumor-induced osteomalacia is a rare condition caused by excess production of phosphatonins most notably fibroblast growth factor−23 (FGF-23), by the tumor cells, leading to phosphate wasting and consecutive severe hypophosphatemia. This results in patient developing gradually progressive muscle weakness and bone loss resulting in severe osteomalacia, making the patient bedbound. These tumors are mostly benign mesenchymal tumors, which remain hidden in soft tissues or bone and thus are difficult to diagnose. And in the presence of normal serum calcium and parathyroid levels with only mild alteration of vitamin D levels, the diagnosis gets further delayed causing a lot of apathy to the patient. We hereby present a thorough review of this condition along with our experience in diagnosing and treating this patient. This underlines the fact that a high index of suspicion is required for diagnosing this condition in a patient with persistent complains of fatigue and bone pains. Appropriate investigations done at an early stage can help one in identifying and excising these tumors, bringing about a rapid relief of symptoms and saving the patient from a lot of distress.

English

The efficacy of Coelatura aegyptiaca shell powder (CES, 500 mg/kg BW) was evaluated as a calcium supplement in ovariectomized (OVX) rats for ten weeks of treatment. The biochemical components and the antioxidant properties of the shell powder were determined. The bone mineral density (BMD), bone mineral content (BMC), calcium (Ca) and phosphorus (P) contents in serum and bone, serum total alkaline phosphatase (TALP) and bone alkaline phosphatase (BALP), serum calcitonin and parathyroid (PTH) hormones were determined. Furthermore, some of the oxidative stress markers [malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (TAC)] were estimated in bone. The current study revealed that CES contained 19.38% Ca, 0.315% P as well as some of antioxidant amino acids which have a potent antioxidant activity against 1,1diphenylpicrylhydrazyl (DPPH) free radical. Administration of CES to OVX rats increased BMD, BMC, tibial Ca and P contents and BALP activity, as compared to OVX rats. An ameliorative effect was recorded in the levels of calcitonin, PTH, MDA, SOD, GPx and TAC subsequent to CES administration to OVX rats.This ameliorative effect of CES powder against osteoporosis may be attributed to its antioxidant efficacy and/or to its Ca content. In conclusion, CES may have the potential to develop a clinically useful anti-osteoporotic agent, since its effect was comparable with alendronate (6.5 mg/kg BW/week).

Falsely Low Parathyroid Hormone Secondary to Biotin Interference: A Case Series

To present a case series on biotin interference in parathyroid hormone (PTH) level measurement. We review the presentation and management of patients at our institution evaluated for unexpectedly low PTH levels while taking biotin supplements in the setting of high or normal serum calcium. Two patients presented with surprising low parathyroid levels--one during preoperative evaluation for hyperparathyroidism and another during postoperative follow-up after subtotal parathyroidectomy. The patients were found to be taking 1,500 mcg and 5,000 mcg of biotin per day, respectively. The role of biotin interference was confirmed in one of the patients when she was retested off biotin, and PTH levels responded appropriately. Biotin supplements remain as unbound molecules in the serum, thus interfering with PTH enzyme-linked immunosorbent assay (ELISA) results and falsely depressing the PTH level. Biotin supplement use has expanded over the years, ranging from medically endorsed therapies to home remedies. Review of the 2 ELISA systems used at our institution demonstrates that free biotin mimics the biotinylated antibody used in the detection process. Screening for biotin use prior to PTH measurement and automatic biotin levels for clinically aberrant PTH levels provide the clinician with a true PTH level--lowering the disease burden of untreated hyperparathyroidism while avoiding unnecessary work-ups for other processes.

Prevalence of Undisclosed Osteoporosis in Patients with Minimal Trauma Fractures: A Prospective Cohort Study

Despite epidemiologic evidence for the presence of osteoporosis in patients with minimal trauma fractures, screening programs have not been routinely established in Australian ambulatory care clinics. Our study assessed the prevalence of osteoporosis and osteopenia in patients at a tertiary care hospital to gather local data to support policy change that favors bone mineral density screening. Our prospective observational study enrolled 115 patients, aged > 40 years, who had experienced a minimal trauma fracture. Inclusion criteria required that the patient had no history of testing for osteoporosis or metabolic bone disease/major pathology. The patients were recruited over a 6-month period. Eleven participants were excluded and 7 participants withdrew from the study, with a total of 97 patients completing the study. Participants were assessed for osteoporosis risk via bone mineral density measurement by dual-energy x-ray absorptiometry and blood screening for bone mineral levels, 25-hydroxyvitamin D, and parathyroid hormone levels. In our study patients, the prevalence of previously undiagnosed osteoporosis was 19%, undiagnosed osteopenia, 50%, and the standard bone mineral density was 32%. The most common risk factors for osteoporosis/osteopenia were smoking (22%), alcohol intake (16%), and corticosteroid use (9%). In 67% of patients, 25-hydroxyvitamin D level was in the low clinical range in 51% of patients, magnesium levels were in the high range and 18% of patients had elevated serum parathyroid levels. At month 12 of our study, 80 participants were available for follow-up: 2 patients had sustained a second fracture (1 was minimal trauma); 6 patients had required further surgery (3 fracture fixations, 3 for removal of internal fixation devices); 26 patients continued treatment regimens with calcium and 25-hydroxyvitamin D supplementation; and 28 patients had been prescribed bisphosphonates, with 22 patients complying with the prescription. The high prevalence of previously undiagnosed low bone mass in our study patient population, each of whom had experienced minimal trauma falls, provides impetus for the provision of osteoporosis screening programs and corresponding treatment as needed.

Survival Rates in Patients with Diabetes on Peritoneal Dialysis in China

Objective: To compare overall survival and technical survival in diabetic mellitus (DM) and non-DM (N-DM) Chinese patients undergoing peritoneal dialysis (PD), and to discuss the factors involved. Methods: Clinical data were analyzed for all adult patients (age >18 years) with chronic renal failure who had commenced PD between 2006 and 2010 in a single Chinese center. Results: Compared to the N-DM group, the DM group was older (64.5 ± 11.9 years vs. 59.2 ± 15.2 years, p = 0.023), with a higher body mass index (BMI) (25.2 ± 3.5 kg/m2 vs. 23.2 ± 3.5 kg/m2, p = 0.001), a higher estimated glomerular filtration rate (eGFR) (10.4 ± 4.7 mL/min/1.73 m2 vs. 6.9 ± 2.9 mL/min/1.73 m2, p = 0.000), and lower intact parathyroid levels (81.35 pg/mL vs. 186.3 pg/mL, p = 0.003). During the average 23.8-month follow-up period, the 1-, 2-, and 3-year survival rates of the DM group were 95.8%, 69.2%, and 60%, respectively. The 1-, 2-, and 3-year survival rates of the N-DM group were 87.2%, 76.5%, and 66.7%, respectively. There was no significant difference in survival between the groups. The 1-, 2-, and 3-year technical survival rates of the DM group were 93.8%, 69.2% and 60%, respectively. The 1-, 2-, and 3-year technical survival rates of the N-DM group were 84.6%, 72.5% and 63.3%, respectively. There was no significant difference in technical survival between the groups. Within the DM group, the only factor predictive for both overall survival (p = 0.015) and technical survival (p = 0.009) was the initial BMI, and both survival outcomes in DM patients with a BMI greater than 24 were higher than those observed with a BMI less than 24. Conclusions: In the first 3 years of PD, DM and N-DM patients have similar survival rates. Chinese DM patients with a higher BMI undergoing PD appear to have higher survival rates than those with a lower BMI.

Evaluation of salivary calcium and salivary parathyroid levels in postmenopausal women with and without oral dryness

Objective:The primary objective of this study is to estimate and secondary objective is to compare the salivary calcium levels, salivary parathyroid hormone (PTH) levels in postmenopausal women with and without oral dryness (OD).Materials and Methods:A case-control study was carried out on 80 selected postmenopausal women. Salivary calcium concentrations were assessed through Semi Autoanalyzer by Arsenazo III reaction. The salivary PTH concentration was measured by the enzyme linked immunosorbent assay. Severity of OD was assessed by a questionnaire through which the xerostomia inventory (XI) score could be measured. Statistical analysis of Student's t-test, Mann-Whitney test and Pearson's correlation was used.Results:There was a significant difference in mean values of both salivary calcium concentration and XI score in postmenopausal women with/without OD (P < 0.001). No statistically significant difference (P > 0.05) was found in salivary parathyroid levels in postmenopausal women in both groups. A positive correlation was found between the salivary calcium concentration and XI score in both case and control groups (P < 0.05).Conclusion:Severity of OD in postmenopausal women is associated with the high levels of salivary calcium. However, the correlation of severity of OD with PTH could not be established.

IMPACT OF SUBCLINICAL PRIMARY HYPERPARATHYROIDISM ON CARDIOVASCULAR MANIFESTATIONS OF ESSENTIAL ARTERIAL HYPERTENSION

At 95 patients with essential arterial hypertension features of structural and functional remodeling of left ventricular and humeral artery depending on a level parathyroid hormone in blood are studied. It is shown that while increasing of plasma parathyroid hormone level frequency and expressiveness of left ventricular and humeral artery remodeling increases whereas diastolic function and endothelium-dependent vasodilatation considerably decrease. Subclinical primary hyperparathyroidism in patients with essential arterial hypertension is detected in 22.1% of cases.

Premenstrual symptoms in dysmenorrheic college students: prevalence and relation to vitamin D and parathyroid hormone levels.

Objectives: To determine the prevalence of premenstrual symptoms (PMS) due to primary dysmenorrhea among a sample of university female students, and to explore possible association with vitamin D and parathyroid (PTH) levels, as well as frequency of consumption of dairy products. Design: A cross-sectional study. Setting: One Jordanian university. Subjects: A total of 177 female students aged between 18 and 24 years who experienced primary dysmenorrhea participated in the study and completed a self administered questionnaire to collect information concerning demographics, menstruation- related information, associated specified premenstrual symptoms, and consumption of dairy products. Plasma 25-hydroxyvitamin vitamin D level and intact parathyroid hormone level were measured. Results: Of the 177 participants 91.5% had two or more symptoms among which fatigue, mood swings, anxiety, abdominal bloating, and depression were the most prevalent symptoms. There was no evident association between presence of symptoms and vitamin D status, PTH level or dairy products consumption. Headaches and social withdrawal were significantly lower in those women who consumed high amounts of dairy products. Conclusion: Premenstrual symptoms are very common in young women with primary dysmenorrhea. PMS has no relation to levels of vitamin D, parathyroid hormone or dairy products consumption. Headache and social withdrawal may be affected by dairy product consumption.

An unusual site for calciphylaxis: a case report

Background: Calciphylaxis is a rare condition characterized by calcification of the tunica media of small arteries with or without endovascular fibrosis, extravascular calcification and vascular thrombosis, leading to tissue ischemia and hence necrosis of tissues supplied by respective vessel. Case report: An 83-year-old lady presented with a 2-week history of rapidly progressing painful necrotic vulval lesion. This patient was being treated medically with bisphosphonates for mild hypercalcaemia secondary to a parathyroid adenoma. The diagnosis of calciphylaxis was made by biopsy of lesion, revealing extensive necrotic areas and multiple abscesses with numerous thrombosed and calcified blood vessels. Conclusions: This case shows an unusual presentation of calciphylaxis, in a patient with primary hyperparathyroidism, in the absence of end stage renal failure. The pathogenesis of the condition is still relatively unknown. Particularly of note in this case is the presentation of the lesion 9 months after the start of treatment with bisphosphonate after the relative decrease of serum parathyroid levels and serum calcium levels. This leads to the question of initiation of the pathology – did the bisphosphonate treatment have an input in initiation of the lesion? The case under review adds a new differential diagnosis to necrotic vulval lesions, other than malignancy.

Restricting dietary magnesium accelerates ectopic connective tissue mineralization in a mouse model of pseudoxanthoma elasticum (Abcc6−/−)

Ectopic mineralization, linked to a number of diseases, is a major cause of morbidity and mortality in humans. Pseudoxanthoma elasticum (PXE) is a heritable multisystem disorder characterized by calcium phosphate deposition in various tissues. The mineral content of diet has been suggested to modify the disease severity in PXE. The aim of this study is to explore the role of diet with reduced magnesium in modifying tissue mineralization in a mouse model of PXE. Abcc6(-/-) mice were placed on either standard rodent diet (control) or an experimental diet low in magnesium at weaning (4weeks) and examined for mineralization in the skin and internal organs at the ages of 1.5, 2 or 6months by computerized morphometric analysis of histopathological sections and by chemical assay of calcium and phosphate. Abcc6(-/-) mice on experimental diet demonstrated an accelerated, early-onset mineralization of connective tissues, as compared to control mice. Wild-type or heterozygous mice on experimental diet did not show evidence of mineralization up to 6months of age. All mice on experimental diet showed decreased urinary calcium, increased urinary phosphate and elevated parathyroid serum levels. However, no difference in bone density at 6months of age was noted. Our findings indicate that the mineral content, particularly magnesium, can modify the extent and the onset of mineralization in Abcc6(-/-) mice and suggest that dietary magnesium levels may contribute to the phenotypic variability of PXE. The control of mineralization by dietary magnesium may have broader implications in general population in the context of vascular mineralization.

Familial hypocalcaemia – think about calcium sensor receptor (CASR)

<h3>Aim</h3> Activating mutations of CaSR gene have been shown to cause hypercalciuric hypocalcaemia1. The CaSR plays a key role in maintaining calcium homeostasis by regulating parathyroid hormone (PTH) and renal calcium reabsorption. Activating mutation of CaSR causes increased sensitivity to Ca++ and hence down regulation of PTH secretion. <h3>Method</h3> This is a case series where we report a pedigree with clinical picture consistent with familial autosomal dominant hypoparathyroidism. The proband, an 18-month-old girl was found to have incidental hypocalcaemia. We identified 4 other affected individuals in the family, including the father of the proband and his twin brother. All affected individuals had mild hypocalcaemia, low normal serum parathyroid levels and borderline high phosphate levels. Treatment with vitamin D and oral calcium did not improve their serum calcium levels. The father of proband has shown evidence of hypercalciuria and has recently been treated for urolithiasis. Mutation analysis identified a novel activating mutation of the CaSR gene [c.407C&gt;T (p.Pro136Leu)] in all 3 family members who were tested. <h3>Conclusion</h3> Activating mutation of the CaSR inhibits PTH secretion and renal calcium reabsorption despite hypocalcaemia. Treatment with vitamin D and calcium can increase hypercalciuria leading to nephrocalcinosis and renal impairment1,2. Asymptomatic individuals should not be overtreated in an attempt to normalise serum calcium.

Study of Primary Hyperparathyroidism

Introduction:The clinical spectrum of primary hyperparathyroidism (PHPT) has undergone a striking change with asymptomatic form predominant in developed countries, whereas symptomatic form predominant in developing countries. In this study, we have analyzed clinical presentation, investigations, management, operative findings in patients with PHPT at our center.Materials and Method:A retrospective, review of medical records of all patients with PHPT between 2000 and July 2012 at our institute was undertaken. A total of 96 patients were included in this study.Results:The mean age of patients was 50.8 years. Of the 96 patients, 63 were females (65.6%) and 33 were males (34.4%). Among them, 17.7% were asymptomatic and 82.3% were symptomatic. Bone pain was the most common complaint (52%) followed by renal stones (27%). Nearly 10.4% were part of familial PHPT, whereas others were sporadic adenomas. All patients had hypercalcemia (range 10.5–19.4 mg/dl) with elevated parathyroid (PTH) levels (range 32–3820 pg/ml). 25(OH) VitD levels were available in 86 patients (89.6%). There was no correlation between VitaminD levels and symptomatology. Sestamibi scan was true positive in 95.6%, false negative 2.2%, and inconclusive in 2.2%. Ultrasonography (USG) results were true positive in 84.2%, false positive in 6.3%, and false negative in 9.5%. Intraoperative PTH levels were measured in 83.3% patients. Postoperative complications were reported in 20.8% patients.Conclusions:Clinical spectrum of PHPT varies but bones and stones are still the predominant manifestations even in affluent society. Asymptomatic form also exists and can be detected by routine measurement of serum calcium. There was no correlation seen between the 25 VitD levels and clinical symptoms.

Transient increases in intraoperative parathyroid levels related to anesthetic technique

Parathyroid hormone (PTH) secretion is partially regulated by circulating catecholamines. We examined the effect of different anesthetic techniques on intraoperative PTH (IOPTH) levels in patients undergoing parathyroidectomy for primary hyperparathyroidism. We prospectively studied 132 patients divided into 3 anesthetic cohorts: monitored anesthetic care (MAC; n = 45), general anesthesia with laryngeal mask airway (LMA; n = 43), or general endotracheal anesthesia (GETA; n = 39). IOPTH levels were drawn before induction and at defined intervals postinduction. All anesthetic techniques increased IOPTH levels from preinduction to 3 minutes postinduction (MAC, 28%; LMA, 45%; GETA, 65%; P < .001). Temporal trends in postinduction IOPTH levels were similar in patients receiving general anesthesia, characterized by a peak effect at 6 minutes. Using a multivariate logistic regression analysis, GETA was >7 times more likely to increase the preinduction IOPTH by ≥ 50% at 3 minutes postinduction compared with MAC (P < .0001). Using immediate postinduction IOPTH levels in surgical decision making would have led to failed surgery in 2 of 6 patients with multiple gland disease receiving GETA. Preincision IOPTH samples should be drawn before induction to avoid incorporation of potentially misleading anesthetic-related IOPTH elevations into surgical decision making.

Influence of renin–angiotensin system on serum parathyroid hormone levels in uremic patients

The aim of this study was to investigate the factors influencing serum parathyroid (PTH) levels, including medications for treating chronic kidney disease-mineral and bone metabolism disorder (CKD-MBD) in patients with end-stage renal disease. We enrolled 1,076 patients in nine Japanese facilities who had begun hemodialysis (HD) due to ESRD. We investigated the relationships between intact PTH (iPTH) levels and clinical parameters and medications just prior to beginning HD. Significant decreases in serum iPTH levels were seen in males, in the presence of diabetes mellitus (DM), and with administration of renin-angiotensin system inhibitors (RASIs). Significant correlations were found between serum calcium and iPTH levels. In the patients administered RASIs, there was a significant decrease in serum iPTH levels with DM, male gender, and administration of active vitamin D sterols (VDs) compared with those not administered RASIs, although serum-corrected calcium levels were not different. Multiple regression analysis found gender, age, presence of DM, and serum calcium and phosphate levels to be significant contributing factors. In addition, administration of angiotensin II receptor blockers (ARBs) may also be a contributing factor to iPTH levels at the beginning HD (p=0.050). In this study, serum iPTH levels were related to administration of ARBs besides gender, age, the presence of DM and serum calcium levels. Our study suggests that the RA system involve serum iPTH levels in uremic patients.

Cinacalcet HCl Suppresses Cyclin D1 Oncogene-Derived Parathyroid Cell Proliferation in a Murine Model for Primary Hyperparathyroidism

Cinacalcet HCl (cinacalcet) is a calcimimetic compound, which suppresses parathyroid (PTH) hormone secretion from parathyroid glands in both primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT). We previously reported the suppressive effect of cinacalcet on PTH secretion in vivo in a PHPT model mouse, in which parathyroid-targeted overexpression of the cyclin D1 oncogene caused chronic biochemical hyperparathyroidism and parathyroid cell hyperplasia. Although cinacalcet suppressed parathyroid cell proliferation in SHPT in 5/6-nephrectomized uremic rats, its effect on PHPT has not yet been determined. In this study, the effect of cinacalcet on parathyroid cell proliferation was analyzed in PHPT mice. Cinacalcet (1mg/g) was mixed into the rodent diet and orally administrated to 80-week-old PHPT mice for 10days before death. 5-Bromo-2'-deoxyuridine (BrdU, 6mg/day) was infused by an osmotic pump for 5days before death, followed by immunostaining of the thyroid-parathyroid complex using an anti-BrdU antibody to estimate parathyroid cell proliferation. Compared to untreated PHPT mice, cinacalcet significantly suppressed both serum calcium and PTH. The proportion of BrdU-positive cells to the total cell number in the parathyroid glands increased considerably in untreated PHPT mice (9.5±3.1%) compared to wild-type mice (0.7±0.1%) and was significantly suppressed by cinacalcet (1.2±0.2%). Cinacalcet did not affect apoptosis in the parathyroid cells of PHPT mice. These data suggest that cinacalcet suppressed both serum PTH levels and parathyroid cell proliferation in vivo in PHPT.

An Optimal Algorithm for Intraoperative Parathyroid Hormone Monitoring

A minimally invasive approach to primary hyperparathyroidism is equivalent to bilateral exploration when intraoperative parathyroid hormone (IOPTH) monitoring is used. The optimal strategy for the monitoring has been debated. There exists an optimal strategy for IOPTH monitoring. Retrospective study. Tertiary referral hospital. A total of 1882 patients underwent parathyroidectomy for primary hyperparathyroidism with IOPTH monitoring. Successful exploration was defined as a 50% or more decline in IOPTH level from baseline and a normal or near-normal IOPTH level at 10 minutes postexcision. These results were compared with those of alternative strategies for IOPTH monitoring, including a 50% decline at 10 minutes, 50% decline at 5 minutes, and normal IOPTH levels at 10 minutes, using the preoperative parathyroid level as baseline. A curative operation was performed in 1830 patients (97.2%). The current strategy had a sensitivity of 96% and an accuracy of 95%. Multiglandular disease was present in 271 patients (14.5%); 134 of 1858 patients (7.2%) whose outcomes failed to reach curative criteria had confirmed multiglandular disease. Using only a 50% decline from baseline as the curative criterion would result in a failed operation in 22.4% of patients with multiglandular disease. A 50% decline at 10 minutes was 96% sensitive and 94% accurate. A 5-minute value was 79% sensitive and 80% accurate. With use of the 5-minute value, unnecessary bilateral exploration would have been performed in 272 of 1460 patients (18.6%) compared with 62 of 1750 patients (3.5%) when using a 10-minute value. A normal 10-minute value is 91% sensitive and 90% accurate. A 10-minute postexcision IOPTH level that decreased 50% from baseline and is normal or near normal is highly successful. Relying on a 50% decrease alone increases the rate of operative failure in patients with multiglandular disease.