Patient Self-Referral for Radiologic Screening Tests: Clinical and Ethical Concerns

Article Figures & Data

Table 1.

Selected Marketed Tests and Their Performance Characteristics among Low-Risk Populations

Test, References	Target Condition(s)	Prevalence (%)*	Sensitivity (%)	Specificity (%)	PPV (%)	Cost (US $)
Whole-body CT1,3–6	Lung cancer^†	0.5	55–86	49–95	1.2–8	500 to 1300
Heart scan (electron beam computed tomography)9	Obstructive coronary artery disease	10	80^‡	40^‡	13	200 to 500
Quantitative ultrasound of the heel8,13–16	Osteoporosis of the hip	6–25	71^‡	73^‡	14–47	15 to 110
Carotid artery duplex sonography 8,17	Carotid stenosis	0.5–10	83–86	89–94	7–61	30 to 150

* Estimated prevalence range of target condition in US adults of age 40 to 70. Point prevalences are the highest likely prevalence in a general screening population.
† For most other plausible target conditions of whole-body CT, insufficient data exist to calculate performance characteristics.
‡ For these tests, sensitivities and specificities shown in the Table are the maximum simultaneous values based on receiver-operating characteristics.
PPV, positive predictive value.