Term
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Definition
| Percentage of individuals with the disease who were positive to the test |
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Term
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Definition
| Percentage of non-diseased subjects who were negative to the test |
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Term
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Definition
| Percentage of subjects with the disease who were negative to the test |
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Term
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Definition
| Percentage of subjects without the disease who were positive to the test |
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Term
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Definition
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Term
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Definition
True -
Total Not Sick *100%
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Term
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Definition
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Term
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Definition
False +
Total Not Sick *100% |
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Term
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Definition
a less expensive, less invasive, high sensitivity screens test if performed first
Those who screen positive are recalled for additional testing with a more expensive, more invasive, high specificity testing
There is a loss in sensitivity but a gain in specificity
Use for screening |
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Term
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Definition
Using two diagnostic tests together
May be used when the available tests are not very sensitive
There is a gain in sensitivity but a loss in specificity
Use for diagnostic purposes |
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Term
| Positive Predictive Value |
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Definition
| The probability of disease in a subject with a positive test result |
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Term
| Negative Predictive Value |
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Definition
| The probability of not having the disease when the test results were negative |
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Term
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Definition
| how common a disease is in a given population |
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Term
| Prevalence and Predictive Value |
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Definition
As prevalence approaches zero, the positive predictive value of a test will also approach zero.
As prevalence approaches 100%, the negative predictive value of a test approaches zero. |
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Term
| Sensitivity Specificity Predictive Value |
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Definition
In a low prevalence disease:
Increasing the sensitivity of the test results in a modest increase in the positive predictive value of the test
Increasing the specificity of the test results in a much larger increase in the positive predictive value |
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Term
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Definition
| values may vary over time |
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Term
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Definition
| A single observer may interpret the same test results differently under different circumstances |
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Term
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Definition
| Two different observers may interpret the same test results differently |
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