hard tissue biochemistry: a comparison of fresh-frozen and formalin-fixed tissue samples.

Formalin fixation of hard tissues alters the levels of some, but not all, of the parameters routinely measured by bone researchers. Although mineral parameters (ash weight, particle size (beta 1/2 002) and Ca/PO4 ratio) and lipid parameters (total lipid content and composition, extractability, and Ca-acidic phospholipid phosphate content) are not affected by formalin fixation, the uronate and DNA contents are reduced in formalin-fixed bone while hydroxyproline content is elevated.