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Diagnostic Test Evaluator

Math Calculators

Sensitivity / specificity / PPV / NPV / Youden

Quick Answer

Diagnostic Test Evaluator: Sensitivity / specificity / PPV / NPV / Youden. Diagnostic Test Evaluator uses standard math formulas to compute accurate results instantly.

How it works

  1. 1Cross-tabulate gold standard × test result
  2. 2Sensitivity=TP/(TP+FN), specificity=TN/(TN+FP)
  3. 3PPV=TP/(TP+FP), NPV=TN/(TN+FN)
  4. 4Youden = sensitivity + specificity − 1, used to pick cut-offs

2×2 table

Sensitivity / Specificity80.0% / 90.0%约登 0.70
PPV：88.9%
NPV：81.8%
Sample prevalence：50.0%
Sensitivity/specificity are intrinsic to the test; PPV/NPV swing hard with prevalence — the same screen at 1% prevalence yields far lower PPV than a 30% clinic population. In low-prevalence screening even high-specificity tests generate many false positives, hence confirmatory testing. The maximal-Youden cut-off is the ROC upper-left point.

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How to Use

  1. Enter values or expressions: type directly into the Diagnostic Test Evaluator — keyboard friendly.
  2. Instant results: everything computes live as you type, no button needed.
  3. Follow the steps: the result panel shows full working and formula substitution.
  4. Copy or recompute: one-click copy; change any input to recalculate instantly.

Key Points

  • Diagnostic Test Evaluator is a free online math tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: Sensitivity / specificity / PPV / NPV / Youden.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Diagnostic Test Evaluator formula

Diagnostic Test Evaluator uses standard math formulas to compute accurate results instantly.

FAQ

How do I use the Diagnostic Test Evaluator?
Open the page and fill in the input fields — results update automatically. Sensitivity / specificity / PPV / NPV / Youden.
Are the results accurate?
Yes. All calculations use standard mathematical formulas and are verified for accuracy.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required — just open and use.
Does it work on mobile?
Yes. The responsive design works on phones, tablets and desktops.
Is my data saved?
No. All calculations run locally in your browser. Nothing is uploaded or stored.

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Source & Updates

Standard mathematical formulas. All logic verified. Last updated: 2025-07

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Diagnostic Test Evaluator[EB/OL]. https://www.yijiansuan.com/en/c/math/sensitivity-specificity

Results provided by this tool are for reference only and do not constitute professional advice.