How to use it
- Setup. Enter the analyte, instrument, lot numbers and your name, and a %CV acceptance threshold (must be greater than 0). For each QC level, enter the previous lot's mean and SD (the %CV is calculated for you; you can enter your recorded %CV to cross-check it) and an allowable bias, either as a % or in absolute units, taken from your lab's own quality specifications.
- Data entry. For each of the 3 QC levels, enter 5 runs on the new lot (negative or non-numeric values are blocked). You'll see the mean, SD, %CV and bias against the previous lot as you type, plus a Levey-Jennings chart you can switch between previous-lot limits (default) and the new lot's own.
- Review & report. Check each level's verdict and the reasons for any flags, add notes, then Print / Save PDF or Export CSV for your records and senior scientist sign-off.
PLACEHOLDER EXAMPLE
Worked example
These numbers are made up purely to show the arithmetic. They aren't real QC data or recommended limits.
Inputs (Level 1): new lot runs 4.9, 5.1, 5.0, 5.2, 4.8; previous lot mean 4.950, SD 0.150; %CV threshold 5%; allowable bias ±3%.
- Mean = 25.0 ÷ 5 = 5.000
- SD (n−1) = √(0.10 ÷ 4) = 0.158
- %CV = 0.158 ÷ 5.000 × 100 = 3.16%, which is ≤ 5%, so the %CV check passes
- 95% CI of the mean = 5.000 ± 2.776 × 0.158 ÷ √5 = 4.804 to 5.196
- Bias = 5.000 − 4.950 = +0.050 (+1.01%), which is within ±3%, so the bias check passes
- Previous lot %CV (calculated) = 0.150 ÷ 4.950 × 100 = 3.03%
Both checks pass with all 5 runs entered, so Level 1 is ACCEPTABLE. With a ±0.04 absolute limit instead, the same data would be flagged Requires review because the bias of 0.050 exceeds 0.04.