1,25-Dihydroxyvitamin D, Serum
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
As a second-order test in the assessment of vitamin D status, especially in patients with renal disease
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)
Differential diagnosis of hypercalcemia
Extraction/Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
1,25-Dihydroxyvitamin D, S
1,25-Dihydroxy Vitamin D
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: At least 1.5 mL
Collection Instructions: Fasting (4-hour preferred but not required)
Forms: If not ordering electronically, submit a General Request Form (Supply T239) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross reject
Mild OK; Gross OK
Mild OK; Gross OK
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum||Refrigerated (preferred)||7 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Vitamin D is a generic designation for a group of fat-soluble, structurally similar sterols including ergocalciferol D2 from plants and cholecalciferol D3 from animals. Vitamin D in the body is derived from 2 sources: exogenous (dietary: D2 and D3) and endogenous (biosynthesis: D3). Endogenous D3 is produced in the skin from 7-dehydrocholesterol, under the influence of ultraviolet light. Both forms of vitamin D are of similar biologic activity.
Vitamin D is rapidly metabolized in the liver to form 25-hydroxy (OH) vitamin D. Additional hydroxylation of 25-OH vitamin D takes place in the kidney by 1-alpha hydroxylase, under the control of parathyroid hormone, to yield 1,25-dihydroxy vitamin D.
1,25-Dihydroxy vitamin D is the most potent vitamin D metabolite. It stimulates calcium absorption in the intestine and its production is tightly regulated through concentrations of serum calcium, phosphorus, and parathyroid hormone.
1,25-Dihydroxy vitamin D levels may be high in primary hyperparathyroidism and in physiologic hyperparathyroidism secondary to low calcium or vitamin D intake. Some patients with granulomatous diseases (eg, sarcoidosis) and malignancies containing nonregulated 1-alpha hydroxylase in the lesion may have elevated 1,25-dihydroxy vitamin D levels and hypercalcemia.
1,25-Dihydroxy vitamin D levels are decreased in hypoparathyroidism and in chronic renal failure.
While 1,25-dihydroxy vitamin D is the most potent vitamin D metabolite, levels of the 25-OH forms of vitamin D more accurately reflect the body’s vitamin D stores. Consequently, 25HDN/83670 25-Hydroxyvitamin D2 and D3, Serum is the preferred initial test for assessing vitamin D status. However, in the presence of renal disease, 1,25-dihydroxy vitamin D levels may be needed to adequately assess vitamin D status.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
<16 years: 24-86 pg/mL
> or =16 years: 18-64 pg/mL
<16 years: 24-86 pg/mL
> or =16 years: 18-78 pg/mL
1,25-Dihydroxy vitamin D concentrations are low in chronic renal failure and hypoparathyroidism.
1,25-Dihydroxy vitamin D concentrations are high in sarcoidosis and other granulomatous diseases, some malignancies, primary hyperparathyroidism, 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.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
No significant cautionary statements.
The new, 1,25-dihydroxy vitamin D liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay correlates well with the current immunoassay:
-LC-MS/MS=0.95 RIA (pg/mL) + 2.5 pg/mL; correlation coefficient=0.822
-Inter-assay precision: 7 to 12% CV (19 to 287 pg/mL)
-Interferences: C-3 epimers (EPI) of 1,25 dihydroxyvitamin D3 3.0%
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Endres DB, Rude RK: Vitamin D and its metabolites. In Tietz Textbook of Clinical Chemisty. Third edition. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Company, 1999, pp 1417-1423
2. Bringhurst FR, Demay MB, Kronenberg HM: Vitamin D (calciferols): metabolism of vitamin D. In Williams Textbook of Endocrinology. Ninth edition. Edited by JD Wilson, DW Foster, HM Kronenberg, PR Larsen. Philadelphia, WB Saunders Company, 1998, pp 1166-1169
Method Description Describes how the test is performed and provides a method-specific reference
Deuterated stable isotopes (d3-1,25 dihydroxyvitamin D3 [DHVD3-d3] and d6-1,25 dihydroxyvitamin D2 [DHVD2-d6]) are added to a 1-mL plasma sample as internal standard. 1,25-Dihydroxyvitamin D2 (DHVD2), 1,25-dihydroxyvitamin D3 (DHVD3), and the internal standard are extracted using acetonitrile precipitation. The extracts are then further purified by SPE and affinity extraction. Extracts are then derivatized using 4-phenyl-1, 2,4-triazoline-3,5-dione (PTAD) and analyzed by chromatography-tandem mass spectrometry using multiple reaction monitoring with a C18 turbo cleanup for excess derivatizing reagent. DHVD2 and DHVD3 are quantified and a total is reported with a clinical reference range attached to the total DHVD.(Unpublished Mayo method)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 3 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|8822||1,25-Dihydroxyvitamin D, S||In Process|