1. Prepare all reagents, samples and standards;
2. Add 50uL standard or sample and 50uL Detection Reagent A to each well. Incubate 1 hours at 37℃;
3. Aspirate and wash 3 times;
4. Add 90uL Substrate Solution. Incubate 10-20 minutes at 37℃;
5. Add 50uL Stop Solution. Read at 450nm immediately.