Table 5.

Predicted failure and efficiency rates of the Wells score and D-dimer testing for excluding DVT and PE in cancer patients

Reference	Cancer patients	All patients
Geersing et al12 (DVT)
N	834	10 002
Failure rate, % (95% CI)	2.2 (0.5-8.6)	1.2 (0.7-1.8)
Efficiency, % (95% CI)	9.1 (5.5-14.7)	28.9 (20.3-39.5)
van Es et al13 (PE)
N	938	7 268
Failure rate fixed D-dimer*, % (95% CI)	2.6 (0.57-11.0)	0.65 (0.38-1.11)
Efficiency fixed D-dimer*, % (95% CI)	9.1 (6.8-12.0)	28.0 (20.5-37.0)
Failure rate age-adjusted D-dimer†, % (95% CI)	1.4 (0.15-12.6)	0.94 (0.58-1.5)
Efficiency age-adjusted D-dimer†, % (95% CI)	13.1 (10.6-16.1)	32.6 (24.6-41.7)

Failure rate is defined as the probability of DVT or PE in those with an unlikely Wells score and a negative D-dimer result. Efficiency rate ia defined as the proportion of patients with an unlikely Wells score and a negative D-dimer result.

^*D-dimer threshold = 500 µg/L.

^†D-dimer threshold = age of patient multiplied by 10 µg/L in patients older than age 50 y.