FSC402HFORENSIC SCIENCE AND THE EXPERT

December 2, 2003

Forensic Issues

Continuity

Quality Assurance

Accreditation

Expert Testimony

Continuity

Continuity, Chain of Custody

The procedures in place that account for the integrity, identification, and security of each specimen by tracking its handling and

storage from its receipt to final disposition.

Continuity

Seals Secure Identity

Security In transit In storage

Receipt

Disposition

Continuity

Seals Secure

Prevents tampering of the item Provides a unique identifier of the item

Identity Provides a unique identifier of the item

Continuity

Security In transit

transferred from site to site by a staff member transfer between areas (eg. CRO to toxicology) is from staff member to staff member

In storage locked rooms sealed containers

Continuity

Receipt

* Record all information*

signs of tampering

item type, seal type, identifier #, attribution

initiate chain of custody

dates

initials

placement of integrity seals if not present

Continuity

Disposition

disposal – biological samples

return to submitter – non-biologicals

under secure seal

* MUST BE RECORDED

Quality Assurance

Quality Assurance

Those planned and systematic actions necessary to provide sufficient confidence that a laboratory's product or service will satisfy given

requirements for quality.

Lab wide

Whole system

Quality Assurance

Quality Control

Internal activities or activities according to externally established standards used to monitor the

quality of analytical data and to ensure that it satisfies specified criteria.

e.g. quality control standard – a standard of known concentration to be tested in the method in

question

may be internal or external

Quality Assurance

Includes: Use of validated procedures

Review of all results and reports technical administrative

Accreditation

Continuing Education

Quality Assurance

Includes: Use of proficiency testing

Comparative testing - analytical Internal quality control samples - analytical External quality control samples - analytical Evaluation of Scientist

expert testimony evaluation of reports

Quality Assurance

Validation of Technical Procedures

Quantitative Procedures Qualitative Procedures- specificity - specificity- accuracy- precision- linear range- limit of quantitation- limit of detection - limit of detection- ruggedness - ruggedness

Quality Assurance

Specificity

ability to measure analyte in the presence of other compounds expected to be found in the matrix

Ruggedness

can the method be duplicated different days different individuals

Quality Assurance

Accuracy

closeness to the true value or expected value

Precision

closeness to each other

Quality Assurance

Limit of Quantification lowest value accurately and precisely measured

Limit of Detection lowest value that can be distinguished from from

background

Linear Range range over which standard curve is accurately and

precisely linear

Accreditation

PURPOSE

To demonstrate that an organization has policies in place to

Assure qualityDetect deficiencies

Take corrective action

Accreditation

PURPOSE

To demonstrate that an organization’s management, operations, personnel, procedures,

equipment, physical plant, security and health and safety procedures meet established standards

Accreditation

SAY WHAT YOU DO

DO WHAT YOU SAY

Accreditation

ASCLD/LAB

American Society of Crime Laboratory Directors

Laboratory Accreditation Board

Accreditation

100% Essential e.g. written or secure electronic chain of custody

70% Important e.g. existence of a quality manual

50% Desired e.g. general cleanliness/good housekeeping

The Expert Witness