Table 3.

Cut-off thresholds (pg/ml) that achieve at least 80% specificity for predicting bone turnover abnormalities with corresponding sensitivities (Sens.), positive predictive values (PPV), and negative predictive values (NPV).

Assay	Low				High
	Cut-off	Sens.	PPV	NPV	Cut-off	Sens.	PPV	NPV
Diasorin	165	0.68	0.69	0.79	404	0.52	0.61	0.76
Elecsys	291	0.68	0.69	0.79	759	0.60	0.65	0.79
Centaur	355	0.74	0.72	0.82	1003	0.49	0.59	0.75
Immulite	550	0.69	0.72	0.80	979	0.51	0.61	0.77
Scantibodies	223	0.58	0.66	0.74	713	0.52	0.61	0.76