IVD Testing Methodologies

Direct answer: Rapid tests use one of two methodologies: colloidal-gold lateral flow (visual, qualitative) or fluorescence immunoassay (analyzer-read, quantitative). Lateral flow is instrument-free and lower-cost; FIA adds numeric results.

Colloidal-gold lateral flowFluorescence immunoassay (FIA)
ReadoutVisual line (naked eye)Fluorescent signal (analyzer-read)
Result typeQualitative / semi-quantitativeQuantitative
InstrumentNoneFluorescence analyzer required
CostLowerHigher

Principle (lateral flow)

A labeled antibody captures the target analyte on a nitrocellulose membrane as the sample migrates by capillary action, producing a visible test line within minutes.

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Frequently Asked Questions

What is the difference between lateral flow and FIA? Lateral flow gives a visual, qualitative result; FIA uses a fluorescent label read by an analyzer for quantitative output.

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References

By Progene Bio Regulatory Affairs Team · Medical Device QA · Medical disclaimer · Last reviewed: 2026-09-12