No-Template Control Turns Yellow (Contamination) (LAMP (Loop-mediated Isothermal Amplification))

Question

Accepted Answer

The no-template control (NTC) reaction turns yellow after incubation at 65°C, indicating contamination with amplifiable target nucleic acid or positive control template. Common causes: 1) Cross-contamination from positive control template during pipetting due to aerosol generation or tip reuse 2) Reagent stocks contaminated with amplicon carryover from previous experiments 3) Work surfaces, pipettes, or equipment contaminated with target nucleic acid or amplicons 4) Improper pipetting technique such as touching tube rims or using same tip for multiple samples Solutions: 1) Replace all reagent stocks including master mix, primers, and water with fresh aliquots from original containers 2) Clean all equipment, pipettes, and work surfaces with 10% chlorine bleach (0.5% sodium hypochlorite) followed by 70% ethanol 3) Implement strict unidirectional workflow: setup area → sample addition area → amplification area → analysis area 4) Use aerosol-barrier pipette tips for all liquid handling steps 5) Change gloves between handling positive controls and setting up other reactions 6) Set up NTC and negative samples before adding positive control template