Hemolysis, a common occurrence in blood collected for chemical analysis, has been reported to affect analytical test results for some analytes depending upon the material tested and the analytical technique employed. The potential for hemolysis to impact blood ethanol determinations using headspace gas chromatography of samples diluted with an internal standard was investigated. A sample of non-hemolyzed blood and a matched sample of hemolyzed blood were both analyzed thirty times for ethanol concentration using headspace gas chromatography. The mean ethanol concentration measured for the non-hemolyzed samples was 0.0639 g/dl. The mean ethanol concentration measured for the hemolyzed samples was 0.0642 g/dl. The calculated t value, 1.897, was less than the critical t value, 2.002, at a 0.05 level of significance. There was no measured statistical difference detected between the mean blood ethanol concentration determined for a hemolyzed whole blood sample and a non-hemolyzed whole blood sample.

Chemical color tests are widely utilized as part of the analytical scheme approved to identify drugs in forensic laboratories and in the field by law enforcement officers.Although these test results are considered preliminary indications of the presence of a drug, forensic scientists sometimes use these test results to direct their confirmatory testing and law enforcement officers use these test results when making arrest decisions and decisions on how to impound evidence. The color tests commonly used to identify cocaine are aqueous cobalt thiocyanate, the Young's test, the Scott's test, and the modified Scott's test. Field testing of a white powder was reported by a law enforcement officer to be positive for cocaine hydrochloride using a commercially available test kit based on the modified Scott's test. The forensic laboratory determined that the powder contained fentanyl and mannitol; cocaine was not detected. Subsequently, the case material, fentanyl and cocaine reference materials, and cocaine cut with mannitol were tested using aqueous cobalt thiocyanate, the Young's test, the Scott's test, and the modified Scott's test. The fentanyl standard and case material produced the colors that would be interpreted as cocaine using the aqueous cobalt thiocyanate and Young's tests. The misidentification of fentanyl as cocaine with these tests could create a potentially hazardous situation. The cocaine containing samples were distinguishable from the fentanyl containing samples with the Scott's and modified Scott's test when 1 mg of cocaine material was tested, whereas a 3-mg cocaine sample produced the same color sequence as fentanyl.

The stability of ethanol in antemortem blood stored under various conditions has been widely studied. Antemortem blood samples stored at refrigerated temperature, at room temperature, and at elevated temperatures tend to decrease in ethanol concentration with storage. It appears that the stability of ethanol in blood exposed to temperatures greater than 38°C has not been evaluated. The case presented here involves comparison of breath test results with subsequent analysis of blood drawn at the time of breath testing. However, the blood tubes were in a refrigerator fire followed by refrigerated storage for 5 months prior to analysis by headspace gas chromatography. The subject's breath was tested twice using an Intoxilyzer 8000. The subject's blood was tested in duplicate using an Agilent headspace gas chromatograph. The measured breath ethanol concentration was 0.103 g/210 L and 0.092 g/210 L. The measured blood ethanol concentration was 0.0932 g/dL for both samples analyzed. Although the mean blood test result was slightly lower than the mean breath test result, the mean breath test result was within the estimated uncertainty of the mean blood test result. Even under the extreme conditions of the blood kit being in a refrigerator fire, the measured blood ethanol content agreed well with the paired breath ethanol test.

Since the accuracy of headspace gas chromatographic analysis of blood for ethanol concentration has been so well established over the past several decades, it has become commonplace in court proceedings to attack preanalytical handling of the blood samples including the lack of measuring sample temperature prior to sample preparation. The impact on measured ethanol concentration of allowing refrigerated (~4℃) samples varying amounts of time to equilibrate with room temperature, 24, 4, 3, 2, and 1 h, prior to sample preparation was evaluated. Samples were diluted 1:10 with an internal standard using a diluter/dispenser and analyzed using headspace gas chromatography. The mean ethanol concentration measured for the sixteen samples at each of the five equilibration times was 0.153 g/dl. The F-critical from the one-way ANOVA was 2.4937. The calculated F value was 0.4209. Additionally, the effect on measured ethanol concentration of having calibrators at different temperatures than case samples was investigated. Three groups were analyzed: all calibrators, controls, and samples given 24 h to equilibrate with room temperature, all calibrators, controls, and samples prepared immediately after removal from refrigeration, and calibrators sampled immediately after removal from refrigerator with samples and controls allowed 24 h to equilibrate with room temperature. The mean ethanol concentration measured for the thirty blood samples in each of the three groups was 0.197 g/dl. The F-critical from the one-way ANOVA was 3.1013. The calculated F value was 0.0188.Measured ethanol concentrations were insensitive to the variations in preanalytical conditions evaluated in this study.

Ethanol stability in preserved antemortem blood has been widely studied since it is a common practice in cases involving suspected impaired driving to collect antemortem blood in evacuated blood tubes containing sodium fluoride. In some situations, antemortem blood is submitted to a forensic laboratory for ethanol analysis in evacuated blood tubes that contain only an anticoagulant. There has been limited research on ethanol stability in antemortem blood stored without a preservative. On two occasions, antemortem blood was collected from five ethanol‐free individuals into 6‐ml Vacutainer® tubes containing only 10.8 mg potassium EDTA. The blood tubes were spiked with ethanol to approximately either 0.08 or 0.15 g/dl. Dual‐FID headspace gas chromatography was used to analyze 58 blood tubes, 29 from each session, for ethanol 1 day after sample collection and again after 1 year of refrigerated storage (~4°C). Statistically significant decreases in ethanol were detected at the 0.05 level of significance. Mean decreases in ethanol after 1 year of storage for the 0.08 and 0.15 g/dl samples were 0.013 and 0.010 g/dl, respectively. The mean ethanol decrease across all tubes was 0.012 g/dl. The range of decreases for the 58 blood tubes was 0.003–0.018 g/dl. The mean ethanol decreases measured in this unpreserved antemortem blood are comparable in magnitude to those previously observed in antemortem blood containing sodium fluoride after 1 year of refrigerated storage. Ethanol did not increase in the antemortem blood samples despite the absence of sodium fluoride.