Find your question below and open its guide. Each guide starts with Run this study: what to prepare, how much to collect, which limits to set first and what to check before reporting. Choose by how you will run the experiment: 20 repeats of one control in one run is repeatability; the same control over 20 days is multi-day precision. To create the study itself, see Start a study.
- Use repeatability for a quick within-run check, for example 20 replicates of a control after maintenance. When replicates span several days or runs, use multi-day precision.
- For the bias of the same replicates against a known value, use bias against an assigned value; both studies can use the same file. For results with no day, run or replicate structure, use a descriptive summary.
- A bias check suits a certified reference material, a proficiency-testing sample with a peer-group mean, or a sample valued by a comparison laboratory. For patient specimens measured by two methods, use method comparison; for a dilution series, use linearity or dilution verification.
- Method comparison suits a new analyzer, a move to another platform or a referral laboratory's method: it gives regression and bias at medical decision levels as well as specimen agreement.
- Instrument comparison suits a main analyzer and its backups, or analyzers on different sites, judged against one reference analyzer.
- Reagent lot comparison suits a new lot on the same analyzer. For imprecision alone, use repeatability or multi-day precision.
- For categorical results such as positive and negative, use qualitative agreement.
- For PT and INR, use normal specimens to establish the mean normal PT for a reagent and instrument, the programming check when applying a mean normal PT or ISI, and the lot comparison when introducing a new reagent lot.
- Linearity suits a dilution or admixture series with known expected concentrations across the measuring range, including expected values derived from measured anchors. For one material with an assigned value, use a bias check.
- Dilution verification suits a laboratory that dilutes high specimens and reports the corrected result.
- Calibration verification suits verifying calibration or collecting analytical measurement range evidence with independent assigned materials.
- Detection limits cover the LoB, LoD or LoQ of a quantitative method. For a qualitative cutoff, use near-cutoff precision.
Verify when the limits already exist; establish when you need new limits from your own healthy subjects. Once created, both show the study type Reference interval.
Qualitative agreement takes one category from each method for each specimen; near-cutoff precision takes repeated testing at known concentrations around the cutoff. For numeric results, use method comparison. Once created, both show the study type Qualitative agreement or near-cutoff precision.
- Stability covers specimens waiting before testing (room temperature, refrigerated, frozen, freeze-thaw), reagent, calibrator or control material over on-board, open-vial or stored time, and comparisons of several storage conditions.
- Carryover is a sample-to-sample check on one analyzer, in the 21-position sequence.
- Interference covers hemolysis, lipemia, icterus, or an added drug or metabolite, as a screen at one or a few concentrations or as a concentration response.
- A descriptive summary suits a quick look at a data set or results that fit no other study.
- Sigma uses bias and imprecision estimates you already have, from studies in the project or from documents, with a total allowable error. For a verdict on bias or imprecision itself, use a bias check or a precision study.
- QC targets set targets for a new QC material, or review an existing QC baseline across instruments, lots and levels.
A study's design is fixed once it has data or a calculation. For a different question, start a new study.
