Intact Fibroblast Growth Factor 23 (FGF23), Serum

Casandra

Casandra Test Code AR84739Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3003816CPT Code 83520

Intact Fibroblast Growth Factor 23 (FGF23), Serum

Also known as: IFGF23

Clinical Use

Order Test

Use

This test may assist in the evaluation of inherited or acquired disorders of mineral metabolism such as hypophosphatemic rickets, tumor-induced osteomalacia, and familial tumoral calcinosis with hyperphosphatemia. Elevated levels of Intact FGF23 are commonly seen in conditions like X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), although normal levels may also be observed. This test is particularly useful for identifying patients suspected of having XLH when Intact FGF23 concentrations exceed 22 pg/mL.

Special Instructions

The test is not performed at ARUP Laboratories; separate specimens must be submitted when multiple tests are ordered. The test methodology is a quantitative sandwich immunoassay manufactured by MedFrontier. Values obtained with different methods may be different and cannot be used interchangeably.

Limitations

Should be interpreted in conjunction with serum phosphate measurements. Intact FGF23 levels may not be indicative of all conditions influencing mineral metabolism. This test is not cleared or approved by the FDA and, if ordered as a tumor marker, results should not be considered conclusive for the presence of malignant disease. Elevated or normal Intact FGF23 levels should also be evaluated with consideration to the individual’s normophosphatemic status.

Test Details

New York Approved