ASTM E2677 Limit of Detection Web Portal
Supporting Information

ASTM subcommittee E54.01 has developed a Standard Test Method for the determination of Limit of Detection (LOD) in trace explosive detectors. The Method was developed following ISO-IUPAC guidelines that harmonize concepts of detection limits1 and considers the observed behaviors of response signals in a wide range of trace detectors. Here, the LOD90 is defined as the lowest amount of a particular substance for which there is 90% confidence that a single measurement will have a true detection probability of at least 90% while the true non-detection probability of a realistic process blank is at least 90%. The LOD90 value is therefore a directly useful metric of trace detector performance and reliability, since the value reflects the practical detection capability of the detector system, influenced by the inherent sensitivity, selectivity, and response variability of the system under realistic deployment conditions.

To obtain the LOD90 value, you enter 0.10 for the confidence limit in the web form. Although 0.10 is the default, you can request a different confidence limit. If you specify a confidence limit of 0.05, this will generate the LOD95 value rather than the LOD90 value. Typical values for the confidence are 0.10, 0.05, and 0.01 corresponding to LOD90, LOD95 and LOD99, respectively. For convenience, the documentation will simply refer to LOD90.

The ASTM Standard Method was developed by a task group at NIST.2 The specific statistical method for LOD determination has been published.3 In order to facilitate the calculations involved for users of the Method, the task group has developed a web-based LOD calculator hosted on a NIST cloud server. The LOD application utilizes the NIST Dataplot program4 and was coded into HTML by Alan Heckert and Keith Kwiatek.

The web-based calculator has been developed to provide the best estimate of the LOD90 value for a particular analyte given the quality of the inputted data. Ideally, data should include a large number of process blank replicates as well as detector responses from a large number of replicates from two mass levels closely straddling the actual LOD90 mass level. By this strategy, the Method is insensitive to many pitfalls that are encountered in commercial trace detectors, including detector response saturation, truncated response distributions, and response heteroscedasticity, i.e. changes in response variation with signal level. Practicalities dictate, however, that a limited number of replicates be analyzed and that mass levels be selected that are wide enough apart to guarantee the straddling of the unknown LOD90 value. By setting the minimum number of required replicates to ten, and by utilizing a short sequence of mass levels that increase by a factor of three, data for the calculation of an adequate LOD90 estimate may be obtained. The web-based calculator has been tested and validated with real and simulated data possessing several types of error structure.

To see a description of the minimum data requirements for the LOD calculator, please see the LOD data input page.

For questions regarding the ASTM Standard Method, please contact


  1. Currie, L.A. (1999) Analytica Chimica Acta 391, 103-134.

  2. Verkouteren, R.M. et al. NIST Special Publication (in progress).
  3. Rukhin, A.L.; Samarov, D.V. (2011) Chemometrics and Intelligent Laboratory Systems 105, 188-194.
  4. Filliben, J.J.; Heckert, N.A.

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Date created: 09/10/2012
Last updated: 02/20/2014
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