Standard Curve
Example of Human FGF-19 standard curve in Assay Diluent GC8. Plotted are the background-subtracted data.
This standard curve is provided for demonstration only.
Human FGF-19 OneStep ELISA Kit
Human FGF-19 OneStep ELISA Kit
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Product Details
Product Details
Product Specification
| Antigen | FGF-19 |
| Immunogen | Recombinant Protein |
| Antibody Type | Recombinant mAb |
| Reactivity | Hu |
| Purification | Protein A |
| Stability & Storage | 12 months from date of receipt / reconstitution, 2 to 8°C as supplied. |
Kit
| Precision | Intra-assay: 3.7%； Inter-assay: 5.1% |
| Sample type | Serum; EDTA Plasma, Citrate Plasma; Cell Culture Supernatant |
| Assay type | Sandwich (quantitative) |
| Sensitivity | 2.09 pg/mL |
| Range | 7.8 pg/mL – 500 pg/mL |
| Recovery | Serum: 98% EDTA Plasma: 98% Citrate plasma: 97% Cell Culture Supernatant: 95% |
| Assay time | 60 minutes |
| Species reactivity | Hu; Mk |
Background
Human FGF-19 (fibroblast growth factor 19) is a member of the endocrine FGF subfamily that functions as a key metabolic regulator rather than a typical mitogenic growth factor. It is primarily synthesized by enterocytes in the ileum in response to bile acid reabsorption and is secreted into the portal circulation. FGF-19 acts on the liver by binding to the FGFR4/β-Klotho receptor complex, where it suppresses bile acid synthesis through inhibition of CYP7A1 expression. Additionally, it plays a major role in postprandial metabolism by promoting glycogen synthesis and reducing hepatic gluconeogenesis. Beyond the liver, FGF-19 also influences gallbladder filling, energy expenditure, and glucose homeostasis. Dysregulation of FGF-19 has been implicated in metabolic disorders such as obesity, type 2 diabetes, and cholestatic liver diseases. Recombinant FGF-19 analogs are being investigated as potential therapeutics for metabolic syndromes and nonalcoholic steatohepatitis (NASH). Consequently, FGF-19 has emerged as a critical molecular target for understanding and treating metabolic and liver-related pathologies.
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ELISA
Spike Recovery
The recovery of Human FGF-19 was evaluated in activated samples spiked with concentrations spanning the entire assay range.
Dilution Linearity
The concentrations of Human FGF-19 were measured and interpolated from the target standard curves and corrected for sample dilution.
The leftmost bar in the graph shows biological samples diluted in Assay Diluent to 25% concentration. "undiluted" was defined as 25% biological sample. The subsequent bars represent two-fold serial dilutions of this reference. The mean target concentration was determined to be 515.6 pg/mL in Human FGF-19.
Dilution Linearity
The concentrations of Human FGF-19 were measured and interpolated from the target standard curves and corrected for sample dilution.
The leftmost bar in the graph shows biological samples diluted in Assay Diluent to 25% concentration. "undiluted" was defined as 25% biological sample. The subsequent bars represent two-fold serial dilutions of this reference. The mean target concentration was determined to be 318.8 pg/mL in Human FGF-19.
Dilution Linearity
The concentrations of Human FGF-19 were measured and interpolated from the target standard curves and corrected for sample dilution.
The leftmost bar in the graph shows biological samples diluted in Assay Diluent to 50% concentration. "undiluted" was defined as 50% biological sample. The subsequent bars represent two-fold serial dilutions of this reference. The mean target concentration was determined to be 13.2 pg/mL in Human FGF-19.
Dilution Linearity
The concentrations of Human FGF-19 were measured and interpolated from the target standard curves and corrected for sample dilution.
The leftmost bar in the graph shows biological samples diluted in Assay Diluent to 50% concentration. "undiluted" was defined as 50% biological sample. The subsequent bars represent two-fold serial dilutions of this reference. The mean target concentration was determined to be 23777.3 pg/mL in Human FGF-19.
Serum levels in healthy individuals
Duplicate measurements were performed on serum samples obtained from ten individual healthy donors. Data are reported as dilution factor-corrected interpolated. The resultant mean FGF19 concentration was 379.3 pg/mL, with a distribution spanning 40.4 to 1049.7 pg/mL across the donor cohort.
Spike-and-dilution Linearity
To evaluate assay linearity, three samples were spiked with high levels of Human FGF-19 in different matrices and serially diluted with the corresponding Calibrator Diluent to fall within the assay's dynamic range.
Spike-and-dilution Linearity
To evaluate assay linearity, sample were spiked with high levels of Human FGF-19 in different matrices and serially diluted with the corresponding Calibrator Diluent to fall within the assay's dynamic range.
Intra-Assay Precision (Precision within an assay)
Three samples of known concentration were tested fifteen times on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays).
Three samples of known concentration were tested in separate assays to assess inter-assay precision. Assays were performed with at least three lots of components.
Determination of Minimum Detectable Dose (MDD)
The MDD was determined using three independent lots of assay components. For each lot, 19 replicate measurements of the diluent (zero calibrator) were performed. The mean (AVERAGE) and standard deviation (STDEV) of the 19 replicates were calculated. The MDD for each lot was then calculated according to the following formula:
MDD = 2 × STDEV + AVERAGE
HOOK Effect Threshold
The upper limit of the HOOK effect was established at 100× the highest calibrator concentration (equivalent to a 2-log10 increase). No HOOK effect was observed below this threshold, confirming that samples within this concentration range yield reliable quantitative results without signal depression.
Comparison of Standard Curves from Three Kits
Standard curves from Company A, Company B, and Starter Onestep were compared.
Protocol Diagram
