This assay has high sensitivity and excellent specificity for detection of Topoisomerase I. No significant cross-reactivity or interference between Topoisomerase I and analogues was observed. Sample types: tissue homogenates, cell lysates and other biological fluids. Range: 0.156-10 ng/mL. Sensitivity: 0.059 ng/mL. Intra-assay Precision (Precision within an assay): 3 samples with low, middle and high level Topoisomerase I were tested 20 times on one plate, respectively. Inter-assay Precision (Precision between assays): 3 samples with low, middle and high level Topoisomerase I were tested on 3 different plates, 8 replicates in each plate.CV (%) = SD/meanX100;Intra-Assay: CV<10%;Inter-Assay: CV<12%. Time: 3 hours