Xiaoqin Shan

A study of blood alcohol stability in forensic antemortem blood samples

The effect of long-term storage on alcohol stability in preserved forensic antemortem blood samples was investigated. Thirty-two whole blood case samples (each with two tubes of blood) were used for this study. One tube from each case was analyzed for blood alcohol concentration (BAC) for court proceedings of driving under the influence (DUI), and all blood samples were then stored under refrigeration. After the storage time (ranging from 13 to 39 months) both tubes of blood for each case were reanalyzed for BAC and the results were compared to the original analysis. Seven samples originally negative for alcohol analysis remained negative. The comparative data for 25 samples demonstrated various losses in BAC in both tubes. A significant loss with a mean of 0.015g/dL, was observed in previously opened tubes compared to a mean loss of 0.010g/dL in unopened tubes. In order to determine the effect of other storage conditions, the same blood samples were then stored at room temperature for 6 months followed by 38°C for 7 and 28 days and analyzed for BAC at the end of each storage time period. The seven alcohol negative cases remained negative when stored at room temperature or at 38°C. Six months of storage at room temperature decreased BAC further for both tubes of the alcohol positive cases with a mean loss of 0.014g/dL. Further storage at 38°C for 7 days did not cause any significant change in BAC. Storage at 38°C for 28 days caused some loss in BAC which was determined to be significant by statistical analysis.

Identification of Volatiles by Headspace Gas Chromatography with Simultaneous Flame Ionization and Mass Spectrometric Detection

Volatiles are frequently abused as inhalants. The methods used for identification are generally nonspecific if analyzed concurrently with ethanol or require an additional analytical procedure that employs mass spectrometry. A previously published technique utilizing a capillary flow technology splitter to simultaneously quantitate and confirm ethyl alcohol by flame ionization and mass spectrometric detection after headspace sampling and gas chromatographic separation was evaluated for the detection of inhalants. Methanol, isopropanol, acetone, acetaldehyde, toluene, methyl ethyl ketone, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane (Norflurane, HFC-134a), chloroethane, trichlorofluoromethane (Freon®-11), dichlorodifluoromethane (Freon®-12), dichlorofluoromethane (Freon®-21), chlorodifluoromethane (Freon®-22) and 1,2-dichlorotetrafluoroethane (Freon®-114) were validated for qualitative identification by this method. The validation for qualitative identification included evaluation of matrix effects, sensitivity, carryover, specificity, repeatability and ruggedness/robustness.

Cost/Benefit Analysis of Case Management Policies in a DUI Lab

A study was previously conducted and published describing the magnitude of the under-reporting of drugs in driving under the influence (DUI) cases by using a blood drug screen (BDS) case management protocol and to determine whether not reporting those drugs would have a meaningful impact on the DUI cases. A follow-up study presented herein was conducted to generate a larger dataset for evaluation and to compare the results to the original study. For this follow-up study of 576 cases, the laboratory BDS protocol was modified so that a BDS was performed for all felony cases and all misdemeanor cases with a BAC < 0.15 g/dL, regardless of the officers request. A cost analysis estimate was also conducted using purchasing and statistical data for calendar year 2014. It was estimated that on average a BDS had a materials cost 30 times greater than a BAC and required over six times as much analyst time. To perform a BDS on every case as has been recommended, the estimated analysis materials cost and analyst time were 218 and 193% of the old protocol, respectively. The results of this follow-up study futher support the insufficiency of presenting drug positivity as a justification for completing drug analysis on every DUI case. For the vast majority of cases with a BAC > 0.08 g/dL, the drugs detected are not significant for supporting a DUI and do not warrant the substantial increase in analysis cost and time required.

Long-Term Blood Alcohol Stability in Forensic Antemortem Whole Blood Samples

The effect of long-term room temperature storage on the stability of ethanol in whole blood specimens was investigated. One hundred and seventeen preserved whole blood case samples (110 of 117 with two tubes of blood in each case) were used for this study. One tube from each case was initially tested for blood alcohol concentration (BAC) for criminal driving under the influence proceedings. Cases positive for ethanol ranged in BAC from 0.023 to 0.281 g/dL. The second tube, if present, remained sealed. All blood samples were then stored at room temperature. After 5.4-10.3 years, the opened tubes were reanalyzed for BAC by the same laboratory that performed the initial testing using the same method and same instrumentation. After the same storage period, the unopened tubes were sent to a different laboratory, using a different method and different instrumentation, and reanalyzed for BAC after a total of 5.6-10.5 years of room temperature storage. Seven samples initially negative for alcohol remained negative. All samples initially positive for ethanol demonstrated a decrease in BAC over time with a statistically significant difference in loss observed based on blood sample volume and whether or not the tube had been previously opened. The decrease in BAC ranged from 0.005 to 0.234 g/dL. Tubes that were not previously opened and were more than half full demonstrated better BAC stability with 89% of these tubes demonstrating a loss of BAC between 0.01 and 0.05 g/dL.

Case Management in a DUI Lab: Effect on Drugs Reported

An evaluation of an internal laboratory decision to implement a protocol for limiting drug testing based on ethanol concentration in laboratory analysis for driving under the influence (DUI) cases is presented. The described case management strategy is supported by known impairment of ethanol at relatively high concentrations, difficulty assigning a level of contributing impairment from drugs in the presence of high ethanol levels and the likelihood that the drug results may be suppressed at trial. Although the results of this study reinforce the assertion that such protocols lead to the under reporting of drugs in DUI cases, for the majority of cases, 95% in this study, the drug analysis results were not significant and did not warrant the time and resources needed for the additional blood drug testing. Furthermore, the study demonstrated that a high drug positivity rate does not necessarily mean that those drug results are legally or pharmacologically meaningful. Additional research should be conducted with quantitative drug results and casework impact of blood drug screen protocols as previous studies only report drug positivity rates and not whether the drug results would be meaningful to the case.