DNA laboratories have come a long way but challenges still exist.

Before 1990, the majority of U.S. forensic laboratories were associated with law enforcement agencies, yet received a relatively small portion of their given agency’s total budget. In general, laboratories performed a range of services including drug testing, firearm examinations, bullet comparisons, paint chip characteristics, assessment of tool marks, serology, handwriting analysis, and fingerprint comparisons. Laboratory personnel received training in fingerprints, basic and advanced blood stain and bullet pattern analysis, evidence collection, and crime scene processing. Due to the length of time and high cost required to obtain probative information, large numbers of samples were not processed.

Law enforcement relied upon forensic laboratories to provide a basic level of discrimination of biological evidence. Analyses of this evidence in cases involving intimate contact were conducted using serological tests such as ABO blood typing and analysis of polymorphic isoenzymes such as Esterase D to enhance the power of discrimination. Discrimination of protein markers was achieved largely through immunological methods or electrophoretic methods using starch gels or isoelectric focusing plates. Phenotyping of biological evidence was possible but required technical expertise and was subject to certain limitations such as the need for fresh semen samples in the analysis of sexual assault evidence. Overall, the typing methods in use provided limited discrimination and lacked the capability to individualize biological evidence. In some cases, individuals who could not be excluded on the basis of serological analysiswere exonerated years later through DNA testing.

In 1988, the Technical Working Group on DNA Analysis Methods (TWGDAM) was established at the Federal Bureau of Investigation in Quantico, Virginia. The success of TWGDAM manifested itself in the publication of quality assurance guidelines for DNA testing¹and raised the bar not only for DNA analysis, but for all forensic disciplines. As the technology matured, the group was renamed SWGDAM, or Scientific Working Group on DNA Analysis Methods, and the concept of the Scientific Working Group (SWG) became formalized. To improve the scientific standards of each of the forensic disciplines, new groups were established to address specific quality assurance needs and set forth guidelines for bestpractices (Figure 1).

Figure 1. Scientific Working Groups for forensic disciplines.

FOLLOWING QUALITY ASSURANCE STANDARDS
In 1995, the DNA Advisory Board (DAB) was formed by congressional mandate under the DNA Identification Act of 1994 as a separate and distinct advisory board administered by the Federal Bureau of Investigation. Initial goals of the DAB were to establish quality standards for forensic DNA testing laboratories and convicted offender DNA databasing laboratories as well as make recommendations as to the feasibility of blind proficiency testing. Using the TWGDAM/SWGDAM guidelines, along with input from a variety of forensic and standards organizations, the DNA Advisory Board presented The Quality Assurance Standards for Forensic DNA Testing Laboratories² to the Director of the FBI. These standards were approved on July 15, 1998, and took effect on October 1, 1998. This was followed by The Quality Assurance Standards for Convicted Offender DNA DatabasingLaboratories³which took effect on April 1, 1999.