| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
PTH, Intact without Calcium
Test Code35202
CPT Codes
83970
Preferred Specimen
1.5 mL plasma collected in an EDTA (lavender-top) tube
Minimum Volume
1 mL
Other Acceptable Specimens
2 mL frozen serum
Instructions
Centrifuge and transfer EDTA plasma to a transport tube. Label as PLASMA.
Transport Temperature
Frozen
Specimen Stability
EDTA plasma
Room temperature: 48 hours
Refrigerated: 72 hours
Frozen: 6 months
Serum
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 6 months
Room temperature: 48 hours
Refrigerated: 72 hours
Frozen: 6 months
Serum
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 6 months
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Plasma submitted in sodium heparin (green-top) tube or lithium heparin (green-top) tube
Methodology
Immunoassay (IA)
Setup Schedule
Set up: Sun-Fri; Report available: Same day
Reference Range
Parathyroid Hormone, Intact
Interpretive Guide
| <1 Year | 7-58 pg/mL | ||||
| 1-7 Years | 12-55 pg/mL | ||||
| 8-18 Years | 12-71 pg/mL | ||||
| ≥19 Years | 14-64 pg/mL | ||||
Interpretive Guide
| Intact PTH | Calcium | |
| Normal Parathyroid | Normal | Normal |
| Hypoparathyroidism | Low or Low Normal | Low |
| Hyperparathyroidism | ||
| Primary | Normal or High | High |
| Secondary | High | Normal or Low |
| Tertiary | High | High |
| Non-Parathyroid | ||
| Hypercalcemia | Low or Low Normal | High |
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.
Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153
