Bone Histomorphometry Laboratory

Tetracycline Labeling

Tetracycline double labeling of bone is used to calculate kinetic data on bone turnover. Tetracycline binds to newly formed bone at the bone/osteoid (unmineralized bone) interface where it shows as a linear fluorescence. If a second dose is given 11-14 days after the first dose, the amount of bone formed during that interval can be calculated by measuring the distance between the two fluorescent labels. While double labeling of bone is necessary to calculate kinetic indices of bone turnover, valuable information can be obtained even if patients have not been labeled with tetracycline. A limited analysis of the bone is possible, and an interpretation may be made based on static indices alone.

A typical tetracycline labeling schedule is as follows:

First label - tetracycline 250 mg tid / three days
Wait 11 - 14 days
Second label - declomycin 300 mg bid / three days
Wait 3 - 5 days
Biopsy the patient

Dairy products and aluminum-containing antacids will interfere with absorption and binding of tetracycline. These should be avoided for two hours before and after medication.

Double Tetracycline Labeling of Bone
Double Tetracycline Labeling of Bone