Lab Test

Vitamin D, 1,25 Dihydroxy

Calcitriol Level , Antrim #32034, EPIC: LAB5844, SOFT: D2OH

Instructions

This test should NOT be used as an initial screen for vitamin D deficiency nor to assess vitamin D toxicity. Vitamin D, 25-Hydroxy is the appropriate test for initial assessment of vitamin D stores.

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)

Physician Office/Drawsite Specimen Preparation

Let specimen clot 30-60 minutes. Centrifuge SST tube to separate serum from cells. Transfer 1.0 mL serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F). (Minimum Serum: 1.0 mL)

Preparation for Courier Transport

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum Serum: 1.0 mL)

Rejection Criteria

  • Plasma specimens. 
  • Severely lipemic, icteric, or grossly hemolyzed specimens. 

Storage

Ambient: 3 days
Refrigerated: 3 days
Frozen: 6 months

Performed

Twice a week.
Results available within 7 days.

Reference Range

19.9 – 79.3 pg/mL.

Test Methodology

Chemiluminescence Immunoassay (CLIA).

Interpretation

1,25-Dihydroxy vitamin D is low in chronic kidney disease, hypoparathyroidism and low or normal in cases of vitamin D toxicity. 1,25-Dihydroxy vitamin D may be high in sarcoidosis, other granulomatous diseases, some malignancies and 1° hyperparathyroidism.

Clinical Utility

1,25-Dihydroxy vitamin D is the active form of vitamin D and is produced primarily in the kidney. Its measurement may be useful in the:

  • Assessment of vitamin D status in patients with significant kidney disease.
  • Differential diagnosis of hypercalcemia when the cause is not clear.
  • As part of the workup to evaluate a patient for possible metabolic bone disease.
  • Investigation of selected patients with vitamin D deficiency when the cause is unclear and/or inherited disorder is suspected (e.g., end-organ resistance to 1,25-dihydroxy vitamin D.

This test should NOT be used as an initial screen for vitamin D deficiency nor to assess vitamin D toxicity. Vitamin D, 25 Hydroxy is the appropriate test for initial assessment of vitamin D stores.

CPT Code

82652

Test Codes

Antrim #32034, EPIC: LAB5844, SOFT: D2OH

Last Updated

7/11/2019

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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.