Tetracycline fluorescence incident photometry: a new technique to quantitate bone formation.

We describe a technique for measuring new bone formation by tetracycline fluorescence incident photometry (TFIP) based on the affinity of tetracycline for newly calcified bone. Unlike traditional fluorescent labeling techniques, which measure appositional bone growth, TFIP measures the total amount of newly labeled bone by quantitating the amount of fluorescent light emitted by tetracycline bound to new bone in response to ultraviolet light excitation. TFIP offers a technically simple and accurate technique for quantitative comparison of new bone formation. It may have broad applications in experimental as well as clinical situation.