Knowledge Base
Guides and analyte explainers for IVD rapid testing — written for buyers and point-of-care users.
Testing Guides
What Is IVD?
In vitro diagnostics explained.
What Is POCT? Point-of-care testing explained.
What Is Immunochromatography? The antibody-based lateral-flow technique.
What Is Colloidal Gold? The gold-nanoparticle label behind rapid tests.
What Is LoD? Limit of detection — the analytical floor.
What Is a Cut-off? The positive/negative threshold.
How Antibodies Are Used in Rapid Tests Capture vs detection, affinity, specificity.
Why False Positives & Negatives Occur Cross-reactivity, window period, matrix, hook effect.
Qualitative vs Quantitative Rapid Tests Line readout vs numeric reader.
What Is an LFIA Reader? Fluorescence vs colloidal gold — when to choose each.
Testing Methodologies Lateral flow vs fluorescence immunoassay (FIA).
Specimen Types Blood, serum, plasma, swab, urine, feces, oral fluid.
Sensitivity & Specificity PPV, NPV and reading test accuracy.
The Diagnostic Window Why timing determines test accuracy.
Screening vs Confirmatory Two-tier diagnosis explained.
Storage & Transport Temperature, shelf life and no cold chain.
How to Read a Result Control line, test line and common errors.
QC Requirements Internal control, lot records, ISO 13485.
Supplier Evaluation Checklist How to evaluate an IVD rapid test supplier.
Analyte Explainers (69)
Adenovirus Alpha-Fetoprotein (AFP) Amphetamine Benzodiazepines Brucella C-Reactive Protein (CRP) Calprotectin Campylobacter Cardiac Troponin (cTnI / cTnT) CEA (Carcinoembryonic Antigen) Chlamydia CK-MB (Creatine Kinase-MB) Clostridium difficile Cocaine (Benzoylecgonine) Cryptosporidium Cytomegalovirus (CMV) D-Dimer Dengue NS1 Antigen Epstein-Barr Virus (EBV) Fecal Occult Blood (FOB) Fentanyl Ferritin Fetal Fibronectin (fFN) Follicle-Stimulating Hormone (FSH) Giardia Gonorrhea Group A Streptococcus (Strep A) Group B Streptococcus (GBS) H-FABP (Heart Fatty Acid-Binding Protein) H. pylori Antigen HbA1c (Glycated Hemoglobin) Hepatitis A (HAV) IgM Hepatitis B Surface Antigen (HBsAg) Hepatitis C Antibodies (Anti-HCV) Hepatitis E (HEV) Herpes Simplex Virus (HSV) HIV p24 Antigen HIV-1/2 Antibodies Human Chorionic Gonadotropin (hCG) iGFBP-1 Ketamine Lactoferrin Legionella pneumophila Luteinizing Hormone (LH) Lyme (Borrelia) Methadone Methamphetamine Microalbumin Morphine Mycoplasma pneumoniae Myoglobin Norovirus NT-proBNP Opiates (Class) Procalcitonin (PCT) Prostate-Specific Antigen (PSA) Respiratory Syncytial Virus (RSV) Rheumatoid Factor (RF) Rotavirus Rubella SAA (Serum Amyloid A) Tetanus THC (Cannabis) Total IgE Toxoplasma Trichomonas vaginalis TSH (Thyroid-Stimulating Hormone) Vitamin D (25-OH) Xylazine
Diagnostic Technology (13)
Colloidal Gold Lateral Flow Immunoassay
Lateral flow immunoassay (LFIA) is the technology behind rapid diagnostic tests — a paper-based strip that detects a target analyte via labeled antibodies and capillary flow, producing a visible line within minutes.
Colloidal Gold Conjugation Conjugation is the process of attaching detection antibodies to colloidal gold nanoparticles (typically ~40 nm), producing the colored label that makes the test line visible.
Nitrocellulose Membrane & Test Lines The nitrocellulose membrane is where the test and control lines are immobilized — the readout zone of a lateral-flow test.
Fluorescence Immunoassay (FIA) Fluorescence immunoassay uses a fluorescent label instead of colloidal gold and is read by a dedicated analyzer, producing quantitative (not just qualitative) results.
Reagent Dispensing & Line Coating The process of dispensing test and control lines onto nitrocellulose membrane, and conjugate onto the conjugate pad, using precision dispensers.
Drying Controlled removal of moisture from dispensed membranes and pads before assembly.
Strip Assembly & Lamination Laminating the sample pad, conjugate pad, membrane and absorbent pad onto a backing card.
Cassette Assembly Cutting laminated cards into strips and loading them into cassettes, panel cups or other housings.
Packaging & Desiccant Sealing finished devices in foil pouches with desiccant to protect against humidity, then labeling and boxing.
Stability & Shelf Life Confirming a test performs consistently across its labeled shelf life and storage range.
Quality Control Lot-level testing against reference panels before release.
Batch Release & Traceability The documented decision to release a manufactured lot for sale.
OEM/ODM Development & Validation Turning a buyer specification — analyte, cut-off, packaging, branding — into a production-ready SKU.