GIFSQ Tools · Module 14 — LIMS & Quality · Tool 268 of 500
Build the conformance check for a certificate of analysis: the result with its expanded uncertainty, guard-banded against the specification.
Try sample values — fills the form with the worked example below.
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Lower guard band
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Upper guard band
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Margin to minimum
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Margin to maximum
Equation: Lower guard band = result − U. Upper guard band = result + U. The result conforms only when the whole interval [result − U, result + U] lies inside [specification minimum, specification maximum]. Margin to minimum = result − specification minimum; margin to maximum = specification maximum − result.
Method: Conformance decision with a guard band per ISO/IEC 17025:2017, clause 7.8.6 (reporting of statements of conformity) and ISO 10576-1 (guarded acceptance): the uncertainty interval, not just the result, must sit inside the specification.
Assumptions: U is the expanded uncertainty at the coverage stated in the method (usually k = 2, about 95%); the specification limits come from the product specification.
Limitations: a guard-banded pass is stricter than a simple result check — a result near the limit can fail here and still be reported with its uncertainty, if the certificate says so.
Rounding: guard bands and margins to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value. Records are kept only in this browser on this device (localStorage); this is a device-only record aid, not a shared multi-user LIMS, and nothing is sent to any server.
Method: Conformance decision with a guard band per ISO/IEC 17025:2017, clause 7.8.6 (reporting of statements of conformity) and ISO 10576-1 (guarded acceptance): the uncertainty interval, not just the result, must sit inside the specification.
Assumptions: U is the expanded uncertainty at the coverage stated in the method (usually k = 2, about 95%); the specification limits come from the product specification.
Limitations: a guard-banded pass is stricter than a simple result check — a result near the limit can fail here and still be reported with its uncertainty, if the certificate says so.
Rounding: guard bands and margins to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value. Records are kept only in this browser on this device (localStorage); this is a device-only record aid, not a shared multi-user LIMS, and nothing is sent to any server.
Worked example: Result 10.2 with U 0.2 against 9.5–10.5: guard band 10.00–10.40, inside the specification — conforms. Margins are 0.70 to the minimum and 0.30 to the maximum.
Enter values above to see results.
Only the laboratory may issue the certificate; this tool prepares the conformance check, it does not sign or issue anything. Tool 268 of 500 — GIFSQ
