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Test Code LAB813 Parathyroid Hormone, Intact with Calcium

Additional Codes

PTH, Intact with Calcium

Includes:

Calcium and PTH

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:

Calcium:

 

Age Reference Range
< 1 year 8.5 - 11.0 mg/dL
1 year - < 19 years 9.2 - 10.5 mg/dL
> 19 years 8.4 - 10.3 mg/dL

 

PTH:

 

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