Independent blood-alcohol sampling verifies state lab’s results
Initial results completed by AIT Labs confirmed reliability of blood-alcohol sample testing performed by the toxicology unit at the state lab. The state lab is part of the Colorado Department of Public Health and Environment.
The test/re-test sample had a Krippendorff’s Alpha coefficient, commonly used to measure internal consistency/reliability, of 99.4 percent, a near perfect positive relationship. The comparison indicates the test and subsequent retest produced essentially the same result.
Karin McGowan, interim executive director of the department said, “We are extremely pleased the independent testing has verified the reliability of the lab’s blood-alcohol testing results.”
On July 3 the state lab suspended blood-alcohol and blood-drug testing performed at its toxicology laboratory until further notice. To verify the reliability of the state lab’s blood-alcohol testing, the lab sent approximately 800 specimens (about 10 percent of the specimens tested over the last 12 months), to be retested by a private lab. AIT labs has returned results on the first 265 of the retested specimens.
Some variation in sampling results by the Colorado laboratory and AIT laboratories in Indiana is expected. Although blood alcohol concentrations are relatively stable, they will decrease over time. Every time a blood sample is opened, a small amount of the alcohol in it will be lost due to evaporation. AIT Laboratories is certified through the American Board of Forensic Toxicology.
No date has been set for resumption of blood-alcohol testing services.
During the suspension, the department is continuing to implement improvements at the toxicology laboratory which include an independent audit, proficiency testing and staff training.
The laboratory continues to maintain successful participation in blood alcohol proficiency testing events required for certification, achieving a score of 100 percent on a June 10, 2013 proficiency test event administered by the College of American Pathologists.
Results on the remainder of the samples sent to AIT for retesting are expected back in early September.