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Enzymes and Protein Markers |
1
Beckman Coulter, Inc., San Diego, CA 92196.
Departments of
2
Pathology and
3
Medical and
Research Technology, University of Maryland School of Medicine,
Baltimore, MD 21201.
a Address correspondence to this author at: Hybritech, Inc., P.O. Box 269006, San Diego, CA 92196-9006. Fax 619-549-9357; e-mail bckress{at}beckman.com.
The performance characteristics of the Tandem®-MP
Ostase® assay, a new microplate immunoassay for
bone-specific alkaline phosphatase (bone ALP; EC 3.1.3.1) in human
sera, are described. Bone ALP is bound to streptavidin-coated
microwells by a single biotinylated anti-bone ALP monoclonal antibody.
Antigen is detected by the addition of p-nitrophenyl
phosphate. The assay is performed at room temperature in <90 min.
Imprecision was 2.36.1% with a detection limit of 0.6 µg/L. Method
comparison of bone ALP measurements with the Tandem-MP Ostase assay and
the mass-based Tandem-R Ostase assay (n = 285) indicated
regression statistics of Tandem-MP Ostase = 1.03 Tandem-R Ostase +
0.22 µg/L, Sy
x = 4.0 µg/L,
r = 0.97. Serum bone ALP values in apparently healthy
men and in pre- and postmenopausal women were also similar between the
two Ostase assay formats. Liver ALP reactivity determined using the
slope and heat inactivation methods was similar in both Ostase assays.
Liver ALP reactivity ranged from 3 µg/L (heat inactivation) to 6
µg/L (slope method) per 100 U/L of liver ALP activity, whereas bone
ALP reactivity was 37 µg/L per 100 U/L of bone ALP activity,
indicating a liver ALP relative reactivity of 8.116.2%. Similar
results were obtained with the Alkphase-B bone ALP immunoassay. The
Tandem-MP Ostase bone ALP assay demonstrated increased concentrations
of serum bone ALP in conditions where bone metabolism is increased and
showed a rapid, temporal decrease in serum bone ALP in Paget disease
patients on bisphosphonate therapy. In conclusion, the Tandem-MP Ostase
assay for serum bone ALP is a rapid, simple, robust nonisotopic
alternative to the Tandem-R Ostase immunoradiometric assay that
provides an accurate and sensitive assessment of bone turnover.
The following articles in journals at HighWire Press have cited this article:
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K. Jung, M. Lein, K. von Hosslin, B. Brux, D. Schnorr, S. A. Loening, and P. Sinha Osteoprotegerin in Serum as a Novel Marker of Bone Metastatic Spread in Prostate Cancer Clin. Chem., November 1, 2001; 47(11): 2061 - 2063. [Full Text] [PDF] |
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