Association false negative

The premarket notification application, 510(k), is reviewed by the FDA scientific staff. This evaluation takes into consideration tumor-associated analytes, test requirements, medical usefulness of the test system for a particular clinical claim, and its application (i.e., monitoring or treatment follow-up). The FDA determines the appropriate performance requirements for each tumor analyte category. The agency s staff considers factors, such as consequences of a false positive or false negative, and the importance or impact of an absolute versus a significant change in the results or values of the tumor marker tests. The performance criteria (parameters) of a particular tumor marker test are compared with those of previously... 

The major drawback of this method is that Bonferroni s Inequality is a conservative correction, especially if some of the hypotheses being tested are not independent. When many SNPs in the same gene are evaluated, for example, and are in LD with each other, the Boneferroni correction would not be appropriate, resulting in the possibility of false negatives or failure to detect a true association. A better approach would be to test the true level of significance directly through simulations. 

Elazard assessment for accidents Eor most materials, dermal exposure is not intended to occur, but it will occur in cases of accidental spillage or mishandling. Elere, it is important to correctly identify the hazard associated with such exposures and be equally concerned with false positives and false negatives. 

If the threshold is critical for health considerations, fewer false negatives would be permitted in either type of assay it is likely in these cases that the threshold would be lowered. The false negative rate should rapidly decrease as the concentration increases above T. The number of false positives that can be tolerated will depend upon the regulatory consequences associated with positive results and the cost of the confirmatory tests. 

In the ideal study, the results of aU patients tested with the test under evaluation are contrasted with the results of a single reference standard. If fewer than all patients are verified with the reference standard, then partial verification exists, and verification bias may occur if the selection of subjects for reference testing is not purely random. For example, if selection is associated with the outcome of the index test, or the strength of prior suspicion, or both, then verification bias is certain. In a typical case, some patients with negative test results (test-negatives) are not verified by the reference standard if this involves a costly or invasive procedure, and these patients are not included in the analysis. This may result in an underestimation of the number of false-negative results. 

The CEA level is elevated in a variety of cancers, such as colorectal (70%), lung (45%), gastric (50%), breast (40%), pancreatic (55%), ovarian (25%), and uterine (40%) carcinoma. Because of the elevations associated with benign disease (i.e., false-positive results) and the number of tumors that do not produce CEA (i.e., false-negative results), CEA testing should not be used for screening. ... 

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