Studybox Research Tool
IVD Study Planner
From a performance target to how many patients, sites and weeks your study needs. Built on FDA's recommended statistics and the minimums in FDA guidance.
Worksheet
Tool
Method
How the Numbers Are Calculated.
- Confidence intervals: two-sided 95% Wilson score intervals, the score method FDA's Statistical Guidance recommends. The planner reproduces the guidance's worked example exactly: 44 of 51 gives 74.3% to 93.2%, and 168 of 169 gives 96.7% to 99.9%.
- Specimens needed: the smallest number of comparator positives (and negatives) for which the chance that the study's lower bound clears the criterion reaches your chosen level, summed over the exact binomial distribution. Because that chance rises in a sawtooth, the planner picks the point from which it stays above your level.
- Why not the simple number: sizing a study so that the expected result just clears the criterion gives roughly a coin-flip chance of passing. The planner shows both so you can see the gap.
- Enrollment: specimens needed divided by positivity and the evaluable rate, then the larger of the positive and negative requirements. FDA minimums for the selected pathway are applied on top.
- Timeline: enrollment divided by sites times per-site pace. With a season window, it also shows how many sites finish inside the window.
§ Sources
- FDA Statistical Guidance for Diagnostic Tests (2007)
- FDA CLIA Waiver Applications guidance (2020)
- FDA Dual 510(k) and CLIA Waiver guidance (2020)
- 21 CFR 866.3328 (influenza antigen special controls)
- 21 CFR 866.3984 (OTC COVID-19 test special controls)
- FDA home-use COVID-19 test template
Educational planning tool, not regulatory or statistical advice. FDA guidance documents are nonbinding; confirm your design with FDA.