STATISTICAL METHODS: HSIL were considered as true positive disease to calculate sensitivity, specificity and predictive values of the screening tests in order to obtain conservative estimates of accuracy and to avoid spectrum bias
The results show that the spectrum bias
of the DR-CAPES method is smaller than that of the FFT method.
This information is important for assessment of spectrum bias
as shown in Figure 2.
(14) must be followed to avoid the various biases (spectrum bias
, verification bias, review bias) affecting the representativeness of diseased and nondiseased individuals and the evaluation of the performance of diagnostic tests.
Because some patients with acute flank pain were not referred for CT, this introduces a spectrum bias
. For example, classic cases may not have been scanned, because the diagnosis was not in doubt.
Although differences in disease severity are often referred to as "spectrum bias
," we view these differences as issues of applicability because they reflect real differences in populations.
Similarly, an analogous plot was used to identify spectrum bias
. Results of individual studies are also reported separately.
When assessing a screening test, we need to know the sensitivity and specificity in the population to be screened to avoid spectrum bias
.[14,15] This is impossible in the case of PSA and prostate cancer screening.
As described in the companion review by Schmidt and Factor in this issue, assessment of spectrum bias
depends on a comparison of patient populations.
With differences as large as this, the influence of spectrum bias
on the results might need to be considered.
(3) quantified the effect of spectrum bias
, which arises when clinicians enroll very ill patients and compare their results with those from healthy controls.
Thus, it can be speculated that because of spectrum bias
, the diagnostic indexes derived in this metaanalysis will be slightly different from those that will be observed in real practice.