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. 2014 May 15;6(5):104–111. doi: 10.4251/wjgo.v6.i5.104

Table 3.

Probability of false positive test results (1-specificity) for commonly used colorectal cancer follow-up tests

Test False positive rate (1-specificity) Ref.
Serum CEA 10% [54]
CT-hepatic metastases 5%-28%1 [55-58]
CT-other abdominal metastases 2% [58]
Contrast enhanced ultrasound-liver 4%-33%2 [56,57,59]
Ultrasound-liver 50% [59]
CT-lungs 4% [58]
Colonoscopy 0% [32]
1

Based on specificity estimates from individual studies of 89%[55] (n = 24), 95%[58] (n = 115), 72%[56] (n = 87), and 91%[57] (n = 100);

2

Based on specificity estimates from individual studies of 96%[60] (n = 68), 96%[57] (n = 99), and 67%[59] (n = 56) subjects. The last was the only to employ intraoperative confirmation of hepatic metastases. The annual probability of at least one false positive test for a patient with no actual recurrence would be 41% in each of year one and two, and 28% in each of year three, four, and five. Over the entire five-year period, the probability of at least one false positive would be 87%. CT: Computed tomography; CEA: Carcinoembryonic antigen.