Order Code IFG23 Intact Fibroblast Growth Factor 23, Serum
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Useful For
Diagnosing and monitoring tumor induced osteomalacia
Diagnosing X-linked hypophosphatemia or autosomal dominant hypophosphatemic rickets
Diagnosing familial tumoral calcinosis with hyperphosphatemia
Method Name
Chemiluminescence-Based Quantitative Sandwich Immunoassay
Reporting Name
Intact Fibroblast Growth Factor 23Specimen Type
SerumSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | 
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days | 
| Frozen | 90 days | 
Reject Due To
| Gross hemolysis | Reject | 
| Gross lipemia | Reject | 
| Gross icterus | OK | 
Reference Values
Pediatric (<18 yrs): ≤52 pg/mL
Adults (≥18 yrs): ≤ 59 pg/mL
Method Description
The intact fibroblast growth factor 23 (FGF23) assay is a 2-site immunoenzymatic assay using 2 anti-human FGF23 mouse monoclonal antibodies. One antibody is coated onto microtiter wells and the other is alkaline phosphatase labeled. The signal generated is proportional to the concentration of intact FGF23 in the serum sample. The amount of intact FGF23 is determined by means of multipoint calibrator curve. Cross-reactivity of the assay with C-terminal FGF23 was evaluated in-house and determined to be no cross-reactivity with C-terminal FGF23 concentrations up to 230,680 pmol/L.(Unpublished Mayo method)
Day(s) Performed
Tuesday, Thursday
Performing Laboratory
 Mayo Clinic Laboratories in Rochester
CPT Code Information
83520
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value | 
|---|---|---|
| IFG23 | Intact Fibroblast Growth Factor 23 | 54390-0 | 
| Result ID | Test Result Name | Result LOINC Value | 
|---|---|---|
| 607216 | Intact Fibroblast Growth Factor 23 | 54390-0 | 
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
Renal Diagnostics Test Request (T830)
Oncology Test Request (T729)