Abstract: A method of assaying a sample of blood or blood components for the presence of 25-hydroxy-vitamin D comprising: (a) lowering the pH of the sample to 5.5 or less to dissociate the 25-hydroxy-vitamin D from vitamin D binding proteins; and (b) determining the concentration of 25-hydroxy-vitamin D in the sample. The vitamin D binding proteins are not removed from the sample.

Abstract: Galactosylhydroxylysine is a terminal degradation product of the bone matrix which thus serves as biochemical marker of bone resorption. A method of synthesizing galactosylhydroxylysine is provided. Antibodies against this synthetically prepared galactosylhydroxylysine conjugated to protein carriers were raised to establish methods to measure galactosylhydroxylysine in biological fluids. The antibodies of the invention recognize native galactosylhydroxylysine and are, for example, useful in the measurement of galactosylhydroxylysine as a biochemical marker of bone resorption in biological fluids. Testing of human serum or adolescent urine resulted in dose-dependent increases in signal intensity using the method of the invention.

Abstract: A method of assaying a sample of blood or blood components for the concentration of an immunophilin ligand comprising incubating the sample with a nonionic detergent and a protease, then inactivating the protease, and subsequently determining the concentration of the immunophilin ligand in the sample.