PTH, Intact and Calcium

The PTH, Intact & Calcium

This discount blood lab test is used to determine the cause of calcium imbalances; to evaluate parathyroid function; to diagnose and differentiate between primary, secondary, and tertiary hyperparathyroidism; to diagnose hypoparathyroidism; during surgery for hyperparathyroidism to confirm removal of the gland(s) causing the problem.

Test Methodology

PTH: Immunoassay (IA) • Calcium: Spectrophotometry (SP)

Reference Range(s)

Calcium

Age Male (mg/dL) Female (mg/dL)
8.4-10.68.4-10.6
1-11 Months 8.7-10.5 8.7-10.5
1-3 Years 8.5-10.6 8.5-10.6
4-19 Years 8.9-10.4 8.9-10.4
20-49 Years 8.6-10.3 8.6-10.2
>49 Years 8.6-10.3 8.6-10.4

Parathyroid Hormone, Intact

Not established
6-9 Years 9-59 pg/mL
10-13 Years 11-74 pg/mL
14-17 Years 9-69 pg/mL
>17 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

The assay is useful in making the diagnosis of primary hyperparathyroidism, secondary hyperparathyroidism, and a differential diagnosis of hypercalcemia. The assay helps in distinguishing hypercalcemia cause by either primary hyperparathyroidism or malignant disease.

Alternative Name(s)

Immunoreactive PTH,Sandwich PTH Assay,PTH Whole Molecule,Intact Hormone,Monogram

The lab estimates that the testing will take 3 to 7 business days. 

Quest test code 8837

Please be advised, that our services are strictly self pay and are not eligible for submission as a claim to your health insurance provider. However, you can submit the receipt for reimbursement to many Flexible Spending and Health Savings Accounts for reimbursement.

 

PTH, Intact and Calcium blood lab test

Test code(s) 8837

 

 Question 1. What is the purpose of this test?

This test is used to:

  • Diagnose and monitor hypo- and hyperparathyroidism
  • Differentiate primary hyperparathyroidism from hypercalcemia of malignancy

Intact PTH is the biologically active form of parathyroid hormone. It acts to increase circulating calcium, decrease circulating phosphorous, and increase the active form of vitamin D [1,25(OH)2D], by mobilizing calcium from bone and retaining calcium in the kidneys.

Question 2. How are test results interpreted?

Results observed in various conditions follow1:

  • Primary hyperparathyroidism: elevated PTH and calcium
  • Hypercalcemia of malignancy: PTH within or below the reference range and elevated calcium
  • Renal failure: elevated PTH and decreased calcium
  • Secondary hyperparathyroidism: elevated PTH and decreased calcium
  • Hypoparathyroidism: decreased PTH and calcium

Question 3. Is there any patient preparation required for this test?

No patient preparation is required.

Question 4. What type of specimen is required?

The preferred specimen is frozen serum.      

Question 5. What can interfere with PTH measurements?

Heterophile antibodies (antibodies to animal immunoglobulins) present in the patient’s blood could cause anomalous results.

Question 6. How can I compare results obtained using different methods?

PTH values vary from one method to the next. You can compare values generated by different methods by comparing where each result falls within the respective method’s reference interval. Calcium values may vary among methods as well and can be compared in the same manner.

Question 7. Where can I go for more information about PTH measurements?

The following reference may be helpful:

Broussard JH, Lepage R, Cardinal H, et al. Influence of glomerular filtration on non-(1-84) parathyroid hormone (PTH) detected by intact PTH assays. Clin Chem. 2000;46:697-703.

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