Used in biomedical research to quantify cyclophosphamide levels in human serum, plasma, or other biological samples. Enables researchers to monitor drug concentration for pharmacokinetic studies, assess compliance in clinical trials, and evaluate metabolic response in patients undergoing chemotherapy. Particularly useful in immunology and oncology research where precise measurement of cyclophosphamide is critical for understanding drug efficacy and toxicity. The ELISA format offers high sensitivity and specificity, allowing detection of low analyte levels with minimal sample volume.