GIFSQ Tools · Module 13 — HACCP, Food Safety & Regulatory Compliance · Tool 255 of 500
Judge an ATP cleaning-verification swab: the reading against your pass and fail limits, the margin to failure, and the pass / caution / fail verdict.
Try sample values — fills the form with the worked example below.
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Reading as % of pass limit
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Margin to fail limit (RLU)
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Verdict
Equation: Reading as % of pass limit = ATP reading ÷ pass limit × 100. Margin to fail limit (RLU) = fail limit − ATP reading. Verdict: Pass when the reading is at or below the pass limit; Caution when it is above the pass limit and at or below the fail limit; Fail when it is above the fail limit.
Method: ATP bioluminescence cleaning verification: the swab reading in relative light units (RLU) is compared with the site’s own pass and fail limits. There is no universal RLU standard — limits are set by the site’s validation and the swab manufacturer’s guidance for the surface and the instrument.
Assumptions: the reading, pass limit and fail limit are all in the same RLU scale from the same instrument and swab type.
Limitations: ATP measures organic residue, not microbes — a passing ATP result does not prove the surface is free of pathogens. Microbial swabs are the separate check.
Rounding: percentages to 2 decimal places; margin to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: ATP bioluminescence cleaning verification: the swab reading in relative light units (RLU) is compared with the site’s own pass and fail limits. There is no universal RLU standard — limits are set by the site’s validation and the swab manufacturer’s guidance for the surface and the instrument.
Assumptions: the reading, pass limit and fail limit are all in the same RLU scale from the same instrument and swab type.
Limitations: ATP measures organic residue, not microbes — a passing ATP result does not prove the surface is free of pathogens. Microbial swabs are the separate check.
Rounding: percentages to 2 decimal places; margin to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Reading 120 RLU against pass 150 and fail 300: 80.00% of the pass limit, margin 180.00 RLU to the fail limit — Pass.
Enter values above to see results.
Pass and fail limits are yours — set them from your own validation data and the swab maker’s guidance, never from another site’s numbers. Tool 255 of 500 — GIFSQ
