Clinics and Departments

Laboratory Services

Lab Dept:

Chemistry

Test Name:

VITAMIN D, 1,25 DIHYDROXY

General Information

Lab Order Codes:

D125

Synonyms:

1,25-Dihydroxycholecalciferol; Calcitriol

CPT Codes:

82652 – Dihydroxyvitamin D, 1, 25-

Test Includes:

Vitamin D, 1, 25-Dihydroxy level reported in pg/mL.

Logistics

Test Indications:

As a second-order test in the assessment of vitamin D status, especially in patients with renal disease and parathyroid dysfunction. The circulating half life is relatively short and therefore it is not ideal for overall vitamin D assessment/nutritional assessment.

Investigation of some patients with clinical evidence of vitamin D deficiency (eg, vitamin D-dependent rickets due to hereditary deficiency of renal 1-alpha hydroxylase or end-organ resistance to 1,25-dihydroxy vitamin D)

Lab Testing Sections:

Chemistry - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: 8822/DHVD)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

2 - 4 days, test set up Monday – Friday.

Special Instructions:

See Patient Preparation

Specimen

Specimen Type:

Blood

Container:

Red top tube

Draw Volume:

4.5 mL (Minimum: 2.1 mL) blood

Processed Volume:

1.5 mL (Minimum: 0.7 mL) serum

Collection:

Routine venipuncture. Forward to laboratory promptly.

Special Processing:

Lab Staff: Centrifuge specimen, remove serum aliquot into a screw-capped round bottom plastic vial. Store and ship at refrigerated temperatures. Forward promptly.

Note: Specimens submitted less that the minimum of 1.2 mL will result in a phone call requesting additional specimen. If more specimen is not available, testing will be canceled.

Patient Preparation:

Patient should be fasting at least 4 hours, recommended but not required.

Sample Rejection:

Gross hemolysis; gross lipemia; grossly icteric; mislabeled or unlabeled specimens

Interpretive

Reference Range:

Females

0 – 15 years:

24 – 86 pg/mL

≥16 years:

18 – 78 pg/mL

Males

0 – 15 years:

24 – 86 pg/mL

≥16 years:

18 – 64 pg/mL

Interpretation:
1,25-Dihydroxy vitamin D concentrations are low in chronic renal failure and hypoparathyroidism and high in sarcoidosis and other granulomatous diseases, some malignancies, primary hyperthyroidism, and physiologic hyperparathyroidism.

1,25-Dihydroxy vitamin D concentrations are not a reliable indicator of vitamin D toxicity; normal (or even low) results may be seen in such cases.

Critical Values:

N/A

Limitations:

N/A

Methodology:

Extraction/Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

References:

Mayo Medical Laboratories Web Page July 2013

Updates:

7/11/2008: Minimum volume serum increase from 0.65 to 1.2 mL.
11/20/2008: Specimen handling for short specimens.



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