We conducted a multicenter, prospective, non-interventional study to determine reference ranges for intact PTH in apparently healthy, normocalcemic, normophosphatemic individuals according to vitamin D status, using the Elecsys® PTH and Elecsys® Vitamin D total II electrochemiluminescence immunoassays. Volunteers were enrolled at three geographic sites across the USA (Century Clinical Research Inc., Daytona Beach, Florida, USA; NB Research, Indianapolis, Indiana, USA; Prism Research, LLC., St Paul, Minnesota, USA). Prior to study initiation, ethical approval was obtained from relevant institutional review boards. The study was conducted in accordance with the principles of the Declaration of Helsinki and International Conference on Harmonisation guidelines for Good Clinical Practice; all participants provided written informed consent.
Apparently, healthy individuals aged ≥ 21 years with body mass index (BMI) 18–30 kg/m2 were enrolled. Key inclusion criteria were: calcium (≤ 60 years, 8.6–10.0 mg/dL; > 60 years, 8.8–10.2 mg/dL), phosphate (2.5–4.5 mg/dL), and creatinine (female 0.51–0.95 mg/dL; male 0.67–1.17 mg/dL), based on medical history and confirmatory testing; geographic location within ± 2° latitude or 138 miles north/south of collection site for ≥ 4 weeks. Key exclusion criteria were pregnancy (self-declared/≤ 12 months); breastfeeding or lactation (≤ 3 months); endocrine/metabolic disease known to affect vitamin D metabolism or interfering with bone metabolism; abnormal calcium, including hypocalcemia, hypocalciuria, hypophosphatemia, or hypercalcemia caused by primary hyperparathyroidism, vitamin D overdose/intoxication, or cancer; bariatric surgery; vigorous exercise (> 2 h/day); hospitalization/immobilization > 7 days (≤ 3 months); bone fracture (≤ 3 months). Individuals taking the following supplements or drugs influencing bone and calcium/phosphorus metabolism were excluded: PTH analogs and/or modified PTH compound; other anabolic medication; anticonvulsants; antiresorptive drugs, e.g., bisphosphonates, calcitonin; hormone replacement therapy; calcium carbonate; diuretics; fluoride; glucocorticoids; high-dose vitamin D supplements (> 1000 IU/day).
Apparently, healthy individuals aged ≥ 21 years with body mass index (BMI) 18–30 kg/m2 were enrolled. Key inclusion criteria were: calcium (≤ 60 years, 8.6–10.0 mg/dL; > 60 years, 8.8–10.2 mg/dL), phosphate (2.5–4.5 mg/dL), and creatinine (female 0.51–0.95 mg/dL; male 0.67–1.17 mg/dL), based on medical history and confirmatory testing; geographic location within ± 2° latitude or 138 miles north/south of collection site for ≥ 4 weeks. Key exclusion criteria were pregnancy (self-declared/≤ 12 months); breastfeeding or lactation (≤ 3 months); endocrine/metabolic disease known to affect vitamin D metabolism or interfering with bone metabolism; abnormal calcium, including hypocalcemia, hypocalciuria, hypophosphatemia, or hypercalcemia caused by primary hyperparathyroidism, vitamin D overdose/intoxication, or cancer; bariatric surgery; vigorous exercise (> 2 h/day); hospitalization/immobilization > 7 days (≤ 3 months); bone fracture (≤ 3 months). Individuals taking the following supplements or drugs influencing bone and calcium/phosphorus metabolism were excluded: PTH analogs and/or modified PTH compound; other anabolic medication; anticonvulsants; antiresorptive drugs, e.g., bisphosphonates, calcitonin; hormone replacement therapy; calcium carbonate; diuretics; fluoride; glucocorticoids; high-dose vitamin D supplements (> 1000 IU/day).
Free full text: Click here
