Lateral-Flow Immunoassay (LFIA)
Definition
A rapid immunological test format using a nitrocellulose membrane strip. An extracted sample migrates by capillary action past antibody-conjugate and capture zones, producing a coloured band when the target antigen is present. Results are available in 5 to 15 minutes without laboratory equipment.
- Format
- Nitrocellulose membrane strip
- Result time
- 5 to 15 minutes
- Equipment needed
- None; point-of-care format
- Application
- Identifying vaginal secretions, urine and other fluids
Common questions
How does a positive LFIA band get confirmed in casework?+
A positive rapid test result is treated as a screening indication, and laboratories typically follow up with a confirmatory method or repeat testing under controlled conditions before the finding is reported as a confirmed body-fluid identification.
What causes a false negative on a lateral-flow strip?+
A degraded or aged sample, an antigen concentration below the strip's detection threshold, or a sample matrix that interferes with antibody binding can all suppress the test line, so a negative result does not conclusively rule out the target fluid.
Related terms
- Cross-Reactivity
- The capacity of an antibody raised against one analyte to bind structurally related compounds. In RIA, cross-reactivity is the main driver of...
- Dermcidin
- An antimicrobial peptide secreted constitutively by eccrine sweat glands. The primary candidate marker for immunological identification of sweat in forensic samples, though...
- Human Leucocyte Elastase (HLE)
- A serine protease secreted by vaginal epithelial cells and leucocytes. The primary immunological target for forensic identification of vaginal secretions, detected using...
- Matrix Metalloproteinase-10 (MMP-10)
- A zinc-dependent endopeptidase present in menstrual blood but not in peripheral blood. The principal marker used in lateral-flow assays designed to distinguish...
- Tamm-Horsfall Protein (Uromodulin)
- The most abundant protein in normal human urine, secreted exclusively by cells of the thick ascending limb of Henle's loop in the...