Osteoporosis-Bone Resorption Marker
hreynolds at uh.edu
hreynolds at uh.edu
Fri Jun 14 13:15:50 EST 1996
The ACTIVE CrossLaps ELISA kit is designed for the specific quantitative
measurement of C-telopeptide degradation products of type I collagen
(CrossLaps) in urine, and is intended for in vitro diagnostic use as an
indicator of human bone resorption.
Type I collagen comprises 90% of the organic matrix of bone and is
synthesized primarily in bone. During bone remodeling, type I collagen
is degraded and the small peptide fragments are excreted in the urine.
The high specificity of the ACTIVE CrossLaps ELISA for this degradation
product of type I collagen makes the quantitative measurement of
CrossLaps an excellent marker of bone resorption.
The ACTIVE CrossLaps ELISA is a 96-well kit featuring the convenience of
a microtitre-plate format, a total assay incubation time of 2 hours and
15 minutes, and sensitivity to 50 µg/L. The standard range of this assay
is 100 - 5000 µg/L of the CrossLaps antigen, and a single urine control
is included with the kit. Due to the biological variability observed
with urine specimens collected at various time points, second morning
void urine sampling is preferred. Additionally, preservatives commonly
used in urine specimens do not affect the performance of the CrossLaps
ELISA. This is an important consideration for assays of urine specimens
since urine is typically collected in the presence of a preservative(s).
The assay is based on the competitive binding of the anti-CrossLaps
antibodies to either soluble CrossLaps antigen or to CrossLaps
antigen-coated microtitration wells. Standards, controls and unknowns
are added to the appropriate wells, then the anti-CrossLaps antibodies
are added, and the wells are incubated for 1 hour. The wells are washed
and peroxidase conjugated anti-rabbit immunoglobulin is added. The wells
are then incubated again for 1 hour. After a second washing step, the
wells are incubated for 15 minutes with a chromogenic substrate (TMB),
and the enzymatic reaction is stopped by the addition of phosphoric
acid. The optical density of each of the wells is read at 450 nm.
The highly specific and sensitive CrossLaps ELISA is an effective tool
for monitoring patient response to anti-resorptive therapies, and
assessing bone resorption activity in patients with metabolic bone
disease. Bone remodeling is a dynamic process whereby bone is degraded
and reformed on a continuous basis. Healthy bone is a balance of these
two processes. Osteoporosis is a disorder characterized by an imbalance
in bone remodeling in which the rate of bone resorption exceeds that of
According to the National Osteoporosis Foundation (NOF), osteoporosis
affects more than 25 million people in the United States, 80 percent of
whom are women. Forty percent of all women have at least one spinal
fracture by the time they reach 80 years of age. One third of all men
will be affected by osteoporosis by age 75. Overall costs associated
with diagnosis and treatment of osteoporosis exceed $10 billion per year
and will likely increase as the aging population continues to grow. In
addition to the use of hormone replacement therapies for postmenopausal
osteoporosis patients, various pharmaceutical agents intended to inhibit
bone resorption are currently in development or under investigation.
Sensitive and responsive assays of exclusive biochemical markers of bone
resorption and bone formation are the rational, cost-effective approach
to monitoring patient response to such anti-resorptive therapies.
In addition to the ACTIVE CrossLaps ELISA kit, DSL offers a comprehensive
panel of assays related to bone metabolism and calcium regulation. The
DSL Bone and Mineral Metabolism product line also features assays for
human osteocalcin, intact-PTH, human calcitonin, salmon calcitonin, and
DSL (Diagnostic Systems Laboratories, Inc.) has received FDA 510(k)
clearance to market the DSL-10-1700, ACTIVE CrossLaps ELISA kit.
The DSL ACTIVE CrossLaps ELISA (catalogue number DSL-10-1700) is
available in North America exclusively from DSL, Inc. For more
information regarding this assay and other DSL products, contact the DSL
Customer Service Center in Webster, TX, USA by phone 800.231.7970 or
713.332.9678, by fax 713.338.1895, or by e-mail mktg at dslabs.com
Diagnostic Systems Laboratories
445 Medical Center Blvd.
Webster, TX 77598
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