Quantitative colorimetric assay. This assay has high sensitivity and excellent specificity for detection of sheep T4. No significant cross-reactivity or interference between sheep T4 and analogs was observed. Note: Limited by current skills and knowledge, it is impossible for us to complete the cross-reactivity detection between sheep T4 and all the analogs, therefore, cross reaction may still exist. Sample types: cell culture supernatants, plasma, serum, tissue homogenates. Range: 20 - 320 ng/ml. Precision: Intra-assay: CV%<15% Inter-assay: CV%<15%.