Setting Up the Design
The Data Entry window has two sections, like other modules: Study Design and the Experiment Data grid. Study Design starts with the current and new lot names, then the design. Units come from the analyte in the test directory. Calculated values stay hidden until you choose Show calculated values.
| Field | Description |
|---|---|
| Carry forward the previous reagent lot comparison? | Yes (the default when the analyte has a signed comparison) reuses that comparison's levels, critical differences and power unchanged and fills the current lot from its new lot. No lets you change the design. With no signed comparison it reads "N/A — first reagent lot comparison for this analyte". |
| Number of levels | One to five concentrations at which the lots are compared, usually near medical decision points or the QC levels. Each extra level needs somewhat more samples, because the 5% chance of wrongly rejecting a good lot is shared across the levels. |
| Power | How likely the comparison is to catch a lot that is off by the critical difference: 80%, 85%, 90% (the default) or 95%. |
| Number of samples | For each level: how many different patient samples to measure, each once on each lot. Legion Diagnostics suggests the fewest that reach the chosen power; you can test more (the check only gets stronger) or fewer (the lower power is shown). Levels may have different numbers of samples. With several levels each tests at least 2; a single level tests at least 3. |
| Target concentration | Levels are numbered Level 1, Level 2…; each one's target concentration is the concentration it checks. Choose patient samples with results close to it. |
| Critical difference based on | Chosen once for all levels, because the analyte has one TEa: TEa − 2 × within-lot SD (the default), Percent of TEa (one share for all levels), or Enter a value for each level. Each level's critical difference still differs, because the TEa is read at that level's concentration. |
| Repeatability / within-lot imprecision | Filled from the package insert's precision claims, in the collapsed Imprecision section. Open it to check or change a level's figures for this comparison (Use package-insert values puts them back); it opens by itself when a level has no claim. |
| Rejection limit | Calculated for the number of samples you test; shown, with each critical difference and its working, under Show calculated values. |
When a Level Cannot Work
If no practical number of samples reaches the chosen power at a level, Data Entry offers the smallest workable critical difference for that level. Choose Use it to apply it, or lower the power instead.
Carrying the Design Forward
Signing the comparison records the decision. The next comparison for the analyte carries this design forward by default.