Studies of serum bone Al-P isoenzyme and serum osteocalcin in patients on maintenance hemodialysis.

This report describes an investigation of 128 patients on maintenance hemodialysis. Their serum bone Al-P isoenzyme (Al-P III) values were measured by the Rosalki method, and simultaneous estimations were made of their serum osteocalcin levels as a diagnostic indicator of renal osteodystrophy (ROD). ROD was evaluated clinically from Jensen's criteria, based on a four-stage classification of the radiographic evidence for subperiosteal resorption: no change (stage 0), minor change (stage I), and definite change (stages IIa and IIb). The serum Al-P III levels in the stage IIa and IIb patients showed significantly elevated values (p less than 0.01), i.e., 4.98 +/- 6.23 and 20.51 +/- 13.46 KAU, respectively. In contrast, their serum osteocalcin levels were not appreciably different. Patients with elevated N-PTH values of 0.30 ng/ml or more were found to have serum Al-P III levels of 20 KAU or more, and all of these patients were categorized under the stage IIb classification. It is concluded therefore that in chronic renal failure patients on hemodialysis, measurements of the serum Al-P III are highly useful for diagnosing ROD, and may also be considered as a critical parameter for assessing the indication for parathyroidectomy (PTX).