| β-CTx

Beta-CrossLaps (β-CTx), the C-terminal telopeptide of type I collagen, is a specific biomarker released into circulation during bone resorption. As a degradation product of bone collagen matrix, elevated β-CTx levels directly reflect increased osteoclastic activity and bone loss, serving as a sensitive indicator for osteoporosis and Paget's disease. Clinically, β-CTx measurement is primarily used to monitor the efficacy of antiresorptive therapies in metabolic bone disorders. Currently recognized as the gold standard for bone resorption assessment, this marker demonstrates superior specificity compared to other available tests. The serum CrossLaps assay specifically detects these carboxy-terminal collagen crosslinks, which are enzymatically cleaved C-telopeptides from fibrillar collagen during bone remodeling.
 

| Typical data

As the OD values of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique, wash technique or temperature effects), the operator should establish a standard curve for each test. Typical standard curve and data are provided below for reference only.

 

Concentration (pg/mL)	8000	4000	2000	1000	500	250	125	0
OD	2.11	1.26	0.8	0.5	0.33	0.24	0.19	0.08
Corrected OD	2.08	1.18	0.72	0.42	0.25	0.16	0.11	-

 

| Repeatability

Intra-assay Precision (Precision within an assay)：CV% < 10%; Inter-assay Precision (Precision between assays)：CV% < 10%
 

| Recovery

The recovery of Rat β-CTx spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

 

Sample Type	Range(%)	Average Recovery(%)
Serum(n=8)	88-102	97
Plasma(n=8)	94-107	104
Cell Culture Supernates(n=8)	96-111	107

 

| Linearity

Samples were spiked with high concentrations of Rat β-CTx and diluted with Universal Diluent to produce samples with values within the range of the assay.

 

		Serum(n=4)	Plasma(n=4)	Cell Culture Supernates(n=4)
1 : 2	Range (%)	82-93	88-96	90-110
	Average (%)	91	93	96
1 : 4	Range (%)	89-103	87-110	105-115
	Average (%)	94	98	109