Interlaboratory Comparison of Autoradiographic DNA Profiling Measurements. 1. Data and Summary Statistics

Currie²,

Reeder³

et al. 1997

Anal. Chem.

Self Cite

The observed total interlaboratory uncertainty in restriction fragment length polymorphism (RFLP) measurements is sufficiently small to be of little significance given current forensic needs. However, as the number of RFLP data increase, further reduction in the total uncertainty could help minimize the resources required to evaluate potential profile matches. The large number of data available enable quantitative estimation of the within-laboratory imprecision and among-laboratory bias contributions to the total uncertainty. Some small but consistent among-laboratory measurement biases can be attributed to specific procedural or materials differences. The bias direction is often fragment-specific and thus unpredictable for unknown samples. Actions that would minimize currently recognized sources of interlaboratory bias include the following: (1) all laboratories should use the same algorithm for data interpolation, (2) all laboratories should use the same sizing ladders, (3) each laboratory should prepare control DNA and sample DNA in the same manner and with the identical reagents, (4) all laboratories should adopt a uniform policy on ethidium bromide use, and (5) all laboratories should adopt the same control DNA sizing acceptability criteria.

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Interlaboratory Comparison of Autoradiographic DNA Profiling Measurements. 4. Protocol Effects

Currie²,

Reeder³

et al. 1997

Anal. Chem.

Self Cite

“…The National Institute of Standards and Technology (NIST) of the U.S. Department of Commerce collaborates with member laboratories of the Technical Working Group for DNA Analysis Methods ( TWGDAM) in the study and documentation of restriction fragment length polymorphism (RFLP) measurement technologies (1)(2)(3)(4)(5)(6)(7). From 1992 to 1996, more than 40 U.S. and Canadian forensic laboratories provided over 100,000 RFLP data from cell line control and other well characterized materials.…”

mentioning

confidence: 99%

Graphical Tools for RFLP Measurement Quality Assurance: Single-Locus Charts

Journal of Forensic Sciences

Liu

Reeder

1999

Self Cite

Forensic restriction fragment length polymorphism analyses typically provide two results for each sample, one result for each unique allele, at each genetic locus probed. In collaboration with the member laboratories of the Technical Working Group for DNA Analysis Methods, we have developed graphical techniques that compactly summarize even large numbers of such paired measurements. This paper provides a detailed description of the basic tool, a modified bivariate control chart for data from one sample at one locus. We demonstrate how various modifications and combinations of these "single-locus charts" can be used for within-and among-laboratory quality assurance activities.

“…The National Institute of Standards and Technology collaborates with member laboratories of the Technical Working Group for DNA Analysis Methods (TWGDAM) in the study and documentation of DNA measurement technologies for human identification (1)(2)(3)(4)(5)(6). While newer technologies are of increasing importance, restriction fragment length polymorphism (RFLP) techniques continue to be used in many forensic and parentage testing laboratories.…”

mentioning

confidence: 99%

“…Kenneth T. Gary, 1 Graphical Tools for RFLP Measurement Quality Assurance: Laboratory Performance Charts* lent to a "Z-score" transformation of all measurement pairs (8)…”

mentioning

confidence: 99%

Graphical Tools for RFLP Measurement Quality Assurance: Laboratory Performance Charts

Gary

Journal of Forensic Sciences

Reeder

1999

Self Cite

Forensic restriction fragment length polymorphism analyses typically provide two band size results at each genetic locus for each sample. In collaboration with the member laboratories of the Technical Working Group for DNA Analysis Methods, we have developed graphical techniques that compactly summarize even large numbers of such paired measurements. This paper provides a detailed description of the basic tool, a modified bivariate control chart for data from multiple samples and/or multiple loci. We demonstrate how various modifications and combinations of these "laboratory performance charts" can be used for quality control, quality assurance, and quality demonstration.