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Change explorer · Haematology and immunology

Point-of-care platelet count vs a central laboratory haematology analyser

Public dataBuilt from a published open-access study.

Central lab haematology analyser compared with point of care haematology analyser: 199 paired results from a published study by Shean and Bennett (2026), re-analysed by NakedSignal as if one laboratory had switched from the first system to the second. At 100, 150 ×10⁹/L, 7 results fall in a different category on the second system than on the first, against about 6 expected from repeat testing alone. That expected count uses a default repeat-test imprecision, the setting our program uses when no precision data are supplied, not one measured in this study, so the two numbers are not a test of whether the switch moves more results than repeat testing would.

Haematology and immunology

Platelet count, ×10⁹/L

Central lab haematology analyser compared with Point of care haematology analyser. 199 paired results.

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Comparison line

The new system reads 1.6% higher than the old system on average. The comparison line (Passing-Bablok) has a slope of 1.007 (95% interval 0.985 to 1.03) and an intercept of 2.308.

Public data
Comparison line, platelet count (×10⁹/L)Comparison line with slope 1.007 (95% interval 0.985 to 1.03) and intercept 2.308, drawn against the line of no change. Decision limits drawn at 100, 150 ×10⁹/L. Where the comparison line sits above the line of no change, the new system reads higher; below, lower.5010015050100150100150No changeComparison lineOld system, ×10⁹/LNew system, ×10⁹/L

Fig. 1. The comparison line against the line of no change, over the range of the decision limits (100, 150 ×10⁹/L). Dots mark where each line meets each limit; the gap between them is the bias at that limit.

Crossing each limit

Results that fall on the other side of a decision limit on the new system than on the old, read as if the new system had 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 (100, 150 ×10⁹/L)

Crossed between the two systems: 7

Expected from repeat testing alone: about 6

Grade and warnings

  • Re-test band: full (at least the protocol minimum of pairs).
  • Band half-width around each limit: 13.48%.
  • Results re-tested on data the band was not fitted to, median: 15%.
  • Repeat-test imprecision: default value.
  • Note: Fewer than 5 results crossed beyond what repeat testing alone would move; excess caught is not meaningful here.

Source

Shean RC, Bennett ST (2026). Clinical Evaluation of a Novel Point-of-Care Hematology Analyzer for Complete Blood Count With Differential. Int J Lab Hematol. doi:10.1111/ijlh.70032 (opens in a new tab); PMC12956494 (opens in a new tab). Licence: CC BY 4.0 (opens in a new tab). Re-analysed by NakedSignal. The deposit names the systems.

Show the numbers
All values for platelet count, Central lab haematology analyser to Point of care haematology analyser
FieldValue
Paired results used199
Comparison line slope1.007393
Slope, 95% interval0.98493 to 1.029707
Comparison line intercept2.30825
Mean difference, new minus old, as % of old1.569
Decision limits (×10⁹/L)100, 150
Crossed between the two systems7
Expected from repeat testing alone5.65
Band half-width (%)13.48
Re-tested, unseen data, median (%)14.57
Re-tested, unseen data, range (%)13.07 to 15.58
Excess caught, line and band (%)none
Excess caught, line alone (%)none

Related

Other comparisons from the same study:

Guide: Crossings by chance

Every study behind the explorer, with its licence: public data. How the counts are made: how it works.

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