, NOTE: Plasma samples from patients with SLE (n = 5) were used. 1. When viruses are suspected to be present in the biological sample, prepare inactivation buffer by adding 200 µL of a non-ioinic surfactant (0.5% nonidet P40 substitute) to 40 mL Detector/Sample diluent

, Centrifuge biological samples containing the analyte of interest at 10,000 g for 15 min at 4 °C to remove cellular debris

, Mix 185 µL Detector/Sample diluent or inactivation buffer with 100 µL biological sample (final dilution factor 3) and 15 µL anti-IFN-? antibody A (initial concentration 1 mg/mL, final concentration 50 ug/mL) or buffer. Incubate for 30 min at room temperature

, Run samples with and without anti-IFN-? antibody in the single molecule array analyser as described above. NOTE: In case of signal saturation, samples should be further diluted. Also, 300 µL is the volume required for duplicate analysis

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