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HelpTest Code LAB108 Parathyroid Hormone, Intact
Additional Codes
PTH, Intact
Notes:
For rapid PTH, call Lab Client Services to schedule at 792-0707
Collection:
Specimen: Blood
Preferred: Lt Green w/ Gel - Li Hep
Acceptable: SST or Red Top
Specimen Volume: 5 mL; Minimum 2.0 mL
Pediatric Collection: Two Lt Green w/ Gel - Li Hep, SST, or Red Top microtainer filled to 500 uL.
Stability:
Separate plasma/serum from gel/cells within 4 hours of collection. Once serum/plasma is separated from cells:
Ambient: 8 Hours
Refrigerated (preferred): 72 Hours
Frozen: 2 Weeks
Turnaround Time (TAT):
STAT: 1 HOUR
Routine: 4 HOURS
Test Availability:
Daily / 24 Hours / Available STAT
Performing Laboratory Section:
Chemistry / UMC MAIN LABORATORY
Reference Interval:
| Age | Reference Range |
|---|---|
| < 6 days | No established reference range |
| 6 days - < 1 year | 6.4 - 88.6 pg/mL |
| 1 year - < 9 years | 16.0 - 63.0 pg/mL |
| 9 years - < 17 years | 22.0 - 88.0 pg/mL |
| 17 years - < 19 years | 16.0 - 60.0 pg/mL |
| > 19 years | 8.5 - 77.1 pg/mL |
Interpretive Data:
Below is an interpretive guide for the clinical association of serum calcium and serum
parathyroid hormone (PTH) levels.
Samples from patients routinely receiving high dose biotin therapy may show falsely depressed results. Careful interpretation of the iPTH result is necessary to evaluate the falsely depressed iPTH values in patients taking high doses of biotin. All iPTH values should be interpreted with a serum calcium value in the context of patient clinical status.
The following table is a limited guide and does not include all possible pathologic
entities associated with derangements of calcium and PTH. It is not intended to substitute for clinical judgement and medical knowledge.
| Calcium Normal | Calcium Elevated | Calcium Decreased | |
| PTH Normal | Normal Parathyroid Status | ||
| PTH Elevated | Secondary HPT (chronic renal disease) with normal or variable calcium. Nephrolithiasis. | Primary HPT (PTH at 1.1 to 7 times upper reference). Familial benign hypercalcemia. Lithium-induced MEN Type II2A. | Secondary HPT (chronic renal disease) with decreased or variable calcium and PTH at 1.5 to >50 times upper reference. Pseudohypoparathyroidism. Renal tubular acidosis. Rickets. |
| PTH Low | PTH low normal or decreased, consider: Hypercalcemia of malignancy (often with severe hypercalcemia). | PTH decreased: Hypoparathyroidism |