Interpreting Your Results
Paired Difference Analysis Table
A separate table is shown for each measurand level tested. For each level, the following are reported:
| Column | What It Tells You |
|---|---|
| Sample Type | Control (no interferent) or Test (maximum interferent concentration). |
| Mean | The mean of replicate measurements for this group at this level. |
| SD | The standard deviation of replicate measurements for this group. |
| Difference, Abs (95% CI) | The absolute difference (Test Mean − Control Mean) with its 95% confidence interval, formatted as: difference (lower, upper). |
| Allowable Diff. | The configured allowable difference for this measurand level, in analyte units. For percentage-based limits, displayed as the converted absolute value. |
| Status | PASS if |Difference| < Allowable Difference; FAIL if |Difference| ≥ Allowable Difference. |
Interference Summary (Dose Response)
The Interference Summary reports the maximum interferent concentration at which the interference effect is expected to remain within the allowable limit with 95% confidence. This is derived from the upper bound of the 95% CI of the regression model — a conservative, worst-case threshold. Concentrations above this value may produce interference bias that exceeds the clinically significant threshold.
General Statistics Table (Dose Response)
The General Statistics table provides observed and modeled statistics for each interferent concentration level:
| Column | What It Tells You |
|---|---|
| Interferent Conc. | The interferent concentration for this row. |
| Mean | The arithmetic mean of all replicate measurements at this interferent concentration. |
| SD | Standard deviation of replicate measurements at this level. Higher SD at a given concentration may indicate the interferent is also affecting measurement precision. |
| CV | Coefficient of variation (SD / Mean × 100%) at this level. |
| % Difference | ((Sample Mean − M0) / M0) × 100. The percentage deviation of the observed mean from the baseline (M0). Provides an intuitive measure of relative interference magnitude. |
| Predicted Mean | The analyte concentration predicted by the regression model at this interferent concentration. |
| Interference Bias | Predicted Mean − M0. The estimated bias attributable to the interferent at this concentration, relative to the zero-interferent baseline. |
| 95% CI | The 95% confidence interval for the interference bias, in analyte units. The upper bound is capped at the configured allowable limit (converted to analyte units if originally entered as a percentage). |
Dose-Response Scatter Plot
The scatter plot visualizes the relationship between interferent concentration and measured analyte concentration. It includes:
- Individual measurements — Each replicate result plotted as a separate point. Spread of replicate points at a given concentration level reflects within-condition variability.
- Sample means — The mean value at each interferent concentration level, plotted distinctly from the individual replicates.
- Quadratic regression curve (green) — The best-fit regression line or curve relating interferent concentration to measured analyte value. The regression equation is displayed above the figure (e.g., Y = β₀ + β₁X + β₂X²). A steep positive or negative slope indicates strong concentration-dependent interference.
- 95% CI bounds (red dotted lines) — The upper and lower confidence bounds for the regression curve. The region between these lines contains the true regression curve with 95% confidence.
- M0 baseline (gray) — A horizontal reference line at the baseline analyte measurement (zero interferent). Deviations from this line represent interference-attributable bias.
A zoom feature is available for closer inspection of the concentration-response relationship in specific regions of interest.