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PTH, Intact
Test CodeINPTH
Preferred Specimen
2 mL serum
Minimum Volume
1 mL
Other Acceptable Specimens
EDTA plasma
Instructions
None
Transport Container
Transport tube
Transport Temperature
Ambeint
Specimen Stability
Ambeint: 12 hours
Refrigerated: 2 days
Refrigerated: 2 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis; Gross lipemia; heparinized plasma
Methodology
Immunoassay (IA)
Setup Schedule
24/7
Report Available
Same day
Reference Range
15.0-65.0 pg/mL
Clinical Significance
This test measures intact parathyroid hormone (PTH) levels in blood and may aid in the differential diagnosis of hypocalcemia and hypercalcemia. This test may also be useful in the diagnosis and management of disorders such as hyperparathyroidism, hypoparathyroidism, hypercalcemia of malignancy, or mineral and bone disorder (MBD) due to chronic kidney disease (CKD) [1-4].
PTH measurement is useful for initial evaluation of hypocalcemia, when low or inappropriately normal PTH levels would suggest a lack of adequate PTH secretion (hypoparathyroidism). For differential diagnosis of hypercalcemia, high or inappropriately normal levels of PTH would suggest over-secretion of PTH (hyperparathyroidism or ectopic PTH production), while low levels point to the possibility of hypercalcemia due to a tumor [1,2]. This test may also be helpful in detecting parathyroid disorders caused by chronic calcium and vitamin D deficiency after bariatric surgery [3]. PTH level is recommended as one of the biomarkers to monitor MBD in patients with CKD, starting at CKD stage G3a [4].
Because interpretation of a PTH result depends upon the calcium level, a simultaneous blood calcium test needs to be acquired [1,2].
This assay uses antibodies directed separately against the N-terminal and C-terminal portions of the PTH molecule, in an immunometric "sandwich" format that detects intact molecules. Therefore, this test is not affected by C-terminal fragments, which can accumulate in renal failure.
This immunoassay employs antibodies; therefore, heterophile antibodies in the patient samples may interfere with test results [2].
This assay is not affected by most drugs or supplements, including biotin [2].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Endres DB, et al. Mineral and bone metabolism. In: Burtis CA, et al. eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th ed. Elserier Inc; 2006:1912-1920.
2. Access intact PTH. Instruction for use. Beckman Coulter, Inc; 2020.
3. Wei JH, et al. Obes Surg. 2018;28(3):798-804.
4. Isakova T, et al. Am J Kidney Dis. 2017;70(6):737-751.
PTH measurement is useful for initial evaluation of hypocalcemia, when low or inappropriately normal PTH levels would suggest a lack of adequate PTH secretion (hypoparathyroidism). For differential diagnosis of hypercalcemia, high or inappropriately normal levels of PTH would suggest over-secretion of PTH (hyperparathyroidism or ectopic PTH production), while low levels point to the possibility of hypercalcemia due to a tumor [1,2]. This test may also be helpful in detecting parathyroid disorders caused by chronic calcium and vitamin D deficiency after bariatric surgery [3]. PTH level is recommended as one of the biomarkers to monitor MBD in patients with CKD, starting at CKD stage G3a [4].
Because interpretation of a PTH result depends upon the calcium level, a simultaneous blood calcium test needs to be acquired [1,2].
This assay uses antibodies directed separately against the N-terminal and C-terminal portions of the PTH molecule, in an immunometric "sandwich" format that detects intact molecules. Therefore, this test is not affected by C-terminal fragments, which can accumulate in renal failure.
This immunoassay employs antibodies; therefore, heterophile antibodies in the patient samples may interfere with test results [2].
This assay is not affected by most drugs or supplements, including biotin [2].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Endres DB, et al. Mineral and bone metabolism. In: Burtis CA, et al. eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th ed. Elserier Inc; 2006:1912-1920.
2. Access intact PTH. Instruction for use. Beckman Coulter, Inc; 2020.
3. Wei JH, et al. Obes Surg. 2018;28(3):798-804.
4. Isakova T, et al. Am J Kidney Dis. 2017;70(6):737-751.
