CLPEX Chat Board

For quality assurance purposes----how does your agency check the reliability of chemicals used to process evidence? Are the tests being done on evidence or on a standard (amino acid, protein,etc.)? If a standard is being used, how is the test set up?

We're going under the new ISO requirements, so yes, you have to test the reliability of the chemicals you are using for processing (this includes CA as well as dye stains, physical developer, amido black, etc.).

We have developed a reagent log that we include with each case notes packet that seems to be working pretty well. It has columns for exhibit number, process number (i.e. where this chemical was used in the sequence), the name of the chemical being used, a description of the standard used (e.g. sebaceous print on acetate, eccrine print on white paper, etc.), the results of the check (e.g. +/- OK), and the lot number of the chemical being tested.

We also are sure to indicate from whom the sebaceous/eccrine/whatever material came, since the source is also important under new ISO standards. Currently, the default is that the standard came from the examiner whose note packet it is, but if another examiner prepared the standard, we say so on the form (e.g. "sebaceous print from MG on acetate"). Mind you, we have not yet had our ISO inspection so I don't know if this will please them, but it's working well operationally and we believe it fulfills the requirements.

As far as how the test is set up, we simply prepare a standard, apply the chemical, and check for the presence of developed prints where they should be (positive) and a lack of reaction where they shouldn't be (negative).

Email me if you need more information.
Heidi