Chemistry
Creatinine, mg/dL
Central lab serum analyser, kinetic Jaffe replaced by Point of care analyser, venous whole blood. 89 paired results.
Compare it with the other comparisons in the explorer
Comparison line
The new system reads 0.6% lower than the old system on average. The comparison line has a slope of 1.429 (95% interval 1.25 to 1.667) and an intercept of -0.343.
Fig. 1. The comparison line against the line of no change, over the range of the decision limits (1.2, 1.5 mg/dL). Dots mark where each line meets each limit; the gap between them is the bias at that limit.
Crossing each limit
Results that moved across a decision limit when the new system replaced the old, against the number repeat testing on one unchanged system would move. The program reports the count across all limits together.
All decision limits together (1.2, 1.5 mg/dL)
Crossed after the change: 1
Expected from repeat testing alone: about 1
Grade and warnings
- Re-test band: Indicative: 89 pairs, below the 100-pair protocol minimum.
- Band half-width around each limit: 27.66%.
- Results re-tested on data the band was not fitted to, median: 13%.
- Repeat-test imprecision: assumed, not measured at this site.
- Warning from the program: The change moved fewer than 5 more people across a line than repeat testing alone would; excess caught is not meaningful here.
Source
Krisher L, Jaramillo D, Dye-Robinson A, Dally M, Butler-Dawson J, Brindley S, Pilloni D, Cruz A, Villarreal Hernandez K, Schaeffer J, Adgate JL, Newman LS (2024). Application and comparison of point-of-care devices for field evaluation of underlying health status of Guatemalan sugarcane workers. PLOS Glob Public Health. doi:10.1371/journal.pgph.0003380 (opens in a new tab); PMC11265697 (opens in a new tab). Licence: CC BY 4.0 (opens in a new tab). Changes: Paired results re-analysed by NakedSignal's program; instruments described generically; only derived results are shown. The deposit names the systems.
Show the numbers
| Field | Value |
|---|---|
| Paired results used | 89 |
| Comparison line slope | 1.428571 |
| Slope, 95% interval | 1.25 to 1.666667 |
| Comparison line intercept | -0.342857 |
| Mean difference, new minus old, as % of old | -0.556 |
| Decision limits (mg/dL) | 1.2, 1.5 |
| Crossed after the change | 1 |
| Expected from repeat testing alone | 1.25 |
| Band half-width (%) | 27.66 |
| Re-tested, unseen data, median (%) | 12.92 |
| Re-tested, unseen data, range (%) | 11.24 to 13.48 |
| Excess caught, line and band (%) | none |
| Excess caught, line alone (%) | none |