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Evaluation of diagnostic tests (view source)
Revision as of 12:02, 19 January 2011
, 12:02, 19 January 2011→Selecting a cut-off for diagnostic tests
| Gaussian (normal) distribution
| Gaussian (normal) distribution
| Previously the most common method of selecting a cut-off
| Previously the most common method of selecting a cut-off
| Easy to use and understand
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| Assumes test results are normally distributed
*Easy to use and understand
Does not take the prevalence of disease into account<br />
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*Assumes test results are normally distributed
No scientific basis for cut-off
*Does not take the prevalence of disease into account<br />
*No scientific basis for cut-off
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|Percentile
|Percentile
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| Does not assume normality
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*Does not assume normality
Simple
Simple
| Does not take prevalence into account
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No scientific basis for cut-off
*Does not take prevalence into account
*No scientific basis for cut-off
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| Risk factor
| Risk factor
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| Practical if risk factor is easy to measure
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|Requires knowledge of risk factors
*Practical if risk factor is easy to measure
PV+ may be low if risk factor is common in population
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*Requires knowledge of risk factors
*PV+ may be low if risk factor is common in population
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| Therapeutic method
| Therapeutic method
| An animal is classified as positive at the point where treatment would be administered
| An animal is classified as positive at the point where treatment would be administered
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| *Requires up to date knowledge of treatment methods
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*Requires up to date knowledge of treatment methods
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| Predictive value method
| [[Predictive value method]]
| Currently the most common method of selecting a cut-off
| Currently the most common method of selecting a cut-off
| *Scientific basis for selecting a cut-off
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*Scientific basis for selecting a cut-off
*Takes charachteristics of the test into account
*Takes charachteristics of the test into account
*Can be altered depending on objective of testing
*Can be altered depending on objective of testing
| *Most complex method
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*Most complex method
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