FGF23
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Fibroblast Growth Factor 23 (Quest), Plasma
Test ID: FGF23QST P
Test
Aliases/Synonyms
Method
ELISA
Method Description
The assay is performed using two affinity purified polyclonal antibodies, specific for the C-terminal portion of the molecule in an ELISA format. Measurement of C terminal specific FGF 23 results in minimal variation among individuals and minimal day to day variation in human samples. The assay measures both the intact molecule and large carboxy-terminal fragments of human FGF 23. FGF 23 standard is a purified preparation and the results are expressed as relative units (RU/ml).
Report Includes
Fibroblast Growth Factor 23 (FGF 23)
Specimens
Plasma
(A similar test is offered with slower turnaround time in a Canadian supplier lab: Fibroblast Growth Factor 23 - Intact (UHN), Plasma)
(A similar test is offered with slower turnaround time in a Canadian supplier lab: Fibroblast Growth Factor 23 - Intact (UHN), Plasma)
Clinical Utility
FGF 23 (Fibroblast Growth Factor 23) – FGF 23 is a major regulator of phosphate homeostasis. It is mainly produced in bone and also in the thymus and brain. Intact FGF 23 is biologically active. High serum FGF 23 levels stimulate FGF 23 expression. It interacts with a specific receptor in renal tubular cells, decreasing the expression of type II a sodium/phosphate cotransponders and resulting in decreased phosphate reabsorption. FGF reduces the formation of 1, 25 dihydroxy vitamin D resulting in reduced phosphate reabsorption. When FGF 23 levels are pathologically elevated with normal renal function, hypophosphatemia with or without osteomalacia occurs. Measurement of serum FGF 23 can assist in the diagnosis and management of disorders of phosphate and bone metabolism. Human FGF 23 measurements can provide an important diagnostic tool for the laboratory evaluation of patients with a variety of hypo and hyperphosphatemic disorders.
Test Location
Quest Diagnostics, California USA
Test Version
5-Jan-2023
Specimen
Specimens
Plasma
(A similar test is offered with slower turnaround time in a Canadian supplier lab: Fibroblast Growth Factor 23 - Intact (UHN), Plasma)
(A similar test is offered with slower turnaround time in a Canadian supplier lab: Fibroblast Growth Factor 23 - Intact (UHN), Plasma)
Collection Containers
Lavender top (EDTA)
Sample Volume
1 mL
Minimum Volume
0.3 mL
Collection & Handling
Handling Information
Store and send frozen.
Stability
| Ambient | Unacceptable |
|---|---|
| Refrigerated | 6 hours |
| Frozen | 90 days |
Rejection Criteria
| Specimen | Not frozen |
|---|
Test Version
5-Jan-2023
Performance / Interpretation
Method
ELISA
Method Description
The assay is performed using two affinity purified polyclonal antibodies, specific for the C-terminal portion of the molecule in an ELISA format. Measurement of C terminal specific FGF 23 results in minimal variation among individuals and minimal day to day variation in human samples. The assay measures both the intact molecule and large carboxy-terminal fragments of human FGF 23. FGF 23 standard is a purified preparation and the results are expressed as relative units (RU/ml).
Turnaround Time
7 days
Results
| Name | Units | Reference Range | Conversion Factor | |
|---|---|---|---|---|
| Fibroblast Growth Factor 23 (FGF 23) | RU/mL |
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(Test performed at Pan Laboratories, 15375 Barranca Parkway, E-101, Irvine, CA 92618-2217)
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Test Location
Quest Diagnostics, California USA
Test Version
5-Jan-2023
Interface / Setup
HL7 Interface Codes
| Order Code | Result Codes | Units |
|---|---|---|
| FGF23QST P | 63573FGF 23 (FIBROBLAST GROWTH FACTOR 23) | RU/mL |
Test Version
5-Jan-2023