Detection Principles¶
Fluorescence Immunochromatography (FICT)¶
FICT is a quantitative lateral-flow immunoassay. A fluorophore-labeled detection antibody binds the analyte, and a dedicated fluorometer measures the fluorescence at the test line — converting signal to concentration via a pre-calibrated standard curve.
How It Works¶
- Sample flows by capillary action along a nitrocellulose membrane.
- Analyte binds capture antibody (test line) and fluorophore-labeled detection antibody (sandwich).
- Excitation light excites the fluorophore.
- Emission is measured and converted to concentration.
Method Comparison¶
| Attribute | FICT | ELISA | PCR |
|---|---|---|---|
| Readout | Fluorescence (quantitative) | Absorbance (quantitative) | Amplification |
| Sensitivity | pg/ml | pg/ml | Attomolar |
| Time | 3–15 min | 1–4 h | 1–4 h |
| Throughput | On-site | Lab batch | Lab batch |
| CV% | < 10% | < 10% | < 5% (Ct) |
Explore This Domain¶
- How FICT Works — the sandwich immunoassay mechanism
- Quantitative vs Qualitative — why instrument-read beats visual
- Understanding LOD/LOQ/CV% — the key analytical parameters
FAQ¶
Why fluorescence instead of colloidal gold? Fluorescence is instrument-read (objective) and linearly proportional to concentration over a wide range — enabling true quantitation, unlike visual gold readout.
Is FICT as sensitive as ELISA? Yes — pg/ml sensitivity, comparable to ELISA for protein analytes.
What does the analyzer actually measure? The fluorescence emission intensity at the test line, converted to concentration via a stored calibration curve.
For the full technical white paper, see the Research Center.
Authored by: Migibio Clinical & Scientific Affairs, Guangzhou Magic Biotech Co., Ltd.
Reviewed by: Migibio R&D Quality Committee
Last updated: 2026-08-13
Disclosure: Migibio (Guangzhou Magic Biotech Co., Ltd.) is the manufacturer of the FIA680/FIA880 analyzers and FICT reagents referenced in this content. See our Editorial & Review Policy.