Used in bone metabolism research to quantify N-terminal telopeptide fragments of type I collagen, a marker for bone resorption. Helps assess osteoclast activity and bone turnover rates in experimental models. Commonly applied in studies of osteoporosis, arthritis, and other metabolic bone diseases. Enables evaluation of drug efficacy in preclinical trials targeting bone loss. Provides a sensitive and specific method for detecting collagen breakdown in cell cultures, serum, or urine samples.