Multicenter evaluation of Iso-ALP test kit for measurement of bone alkaline phosphatase activity in serum and plasma

Abstract

A test kit (Iso-ALP, Boehringer Mannheim) for measuring human bone alkaline phosphatase activity in serum or plasma was evaluated in five laboratories in three countries. The assay is based on the principle described by Rosalki and Foo (Clin Chem 1984;30:1182-6) and uses wheat germ lectin to precipitate bone alkaline phosphatase. Residual ALP in the supernate in comparison with total ALP is used to quantify the bone fraction. The imprecision of residual ALP measurement was low (median between-run CV 4.9%) and comparable with that of total ALP. Linearity of precipitation was demonstrable up to a bone ALP activity (diethanolamine buffer 37 degrees C) of 2000 U/L, though a matrix effect was observed for dilutions of high-activity sera in saline or bovine serum albumin. For assaying patients' samples, different batches of lectin demonstrated excellent comparability. Taking electrophoresis as a basis for standardization, we determined that the lectin precipitated approximately 90% of bone ALP, but < 5% of nonbone ALP. From this we derived serum/plasma upper reference limits for bone ALP activity in adults and children.

Alkaline phosphatase activity in gingival crevicular fluid during canine retraction

“…Therefore, we used a 100‐g sentalloy spring (GAC). The Iso ALP kit manufactured by Boerhinger‐Mannheim for small sample volumes was used keeping in mind the sensitivity of the kit (19).…”

Ibandronate: A Comparison of Oral Daily Dosing Versus Intermittent Dosing in Postmenopausal Osteoporosis

“…Bone‐specific alkaline phosphatase (B‐AP) was measured by the Iso‐ALP (Roche Diagnostics, Mannheim, Germany). The inter‐ and intra‐assay variations were below 5% (8) . Urinary C‐telopeptide of type I collagen (CTx/Cr) was measured by CrossLaps ELISA (Osteometer Biotech) and corrected for urinary creatinine.…”

Treatment-Related Changes in Bone Turnover and Fracture Risk Reduction in Clinical Trials of Anti-Resorptive Drugs: A Meta-Regression

“…Different assays were used to measure the bone formation markers (bone ALP and PINP) and the bone resorption markers (NTX/Cr, sCTX) as described in Table 2. The assays for bone ALP included an immunoradiometric assay (Ostase, Hybritech, La Jolla, CA, USA), a wheat-germ lectin precipitation assay, (19) We chose not to include these markers as they did not include the two markers recommended by the International Osteoporosis Foundation and International Federation of Clinical Chemistry (3) or else they had fewer studies in which they were measured.…”