Effect of hyperthermia on breath-alcohol analysis

Mild hyperthermia to the extent of a 2.5 degrees C increase above normal body temperature was produced by immersion of ethanol-intoxicated subjects in a warm water bath. Hyperthermia did not influence the blood-alcohol decay curve of the subjects. Hyperthermia did cause a significant distortion of the breath-alcohol decay curve, up to as much as a 23% increase above blood-alcohol concentration. The magnitude of this distortion effect was calculated to be a 8.62% increase in breath-alcohol concentration over blood-alcohol concentration for each degree C increase in core body temperature. The forensic relevance of these results is that further support is given to previous recommendations that temperature monitoring be included in procedures for breath-alcohol analysis. This leads to the recommendation that mouth temperature be measured before breath sampling to screen for abnormal body temperature and to allow for potential use of a "temperature correction factor." This modification to existing analytical procedures would optimize the reliability of breath-ethanol analysis for prediction of blood-ethanol concentration.     

Effect of hypothermia on breath-alcohol analysis

Mild hypothermia, induced by experimental immersion of ten subjects in cold water, distorted the decay curve of breath ethanol of intoxicated subjects by as much as 22% while not altering overall ethanol clearance rate. The results provide in vivo verification of the in vitro temperature correction factor of 6.8% X degrees C-1, and support previous recommendations that temperature monitoring be included in procedures for breath-ethanol testing. We recommend that mouth temperature be obtained before breath sampling to screen for abnormal body temperature and to allow for potential use of a temperature correction factor. This modification to existing analytical procedures would help to optimize the reliability of breath-ethanol analysis in predicting blood-ethanol concentration.     

Reliability of breath-alcohol analysis in individuals with gastroesophageal reflux disease.

Gastroesophageal reflux disease (GERD) is widespread in the population among all age groups and in both sexes. The reliability of breath alcohol analysis in subjects suffering from GERD is unknown. We investigated the relationship between breath-alcohol concentration (BrAC) and blood-alcohol concentration (BAC) in 5 male and 5 female subjects all suffering from severe gastroesophageal reflux disease and scheduled for antireflux surgery. Each subject served in two experiments in random order about 1-2 weeks apart. Both times they drank the same dose of ethanol (approximately 0.3 g/kg) as either beer, white wine, or vodka mixed with orange juice before venous blood and end-expired breath samples were obtained at 5-10 min intervals for 4 h. An attempt was made to provoke gastroesophageal reflux in one of the drinking experiments by applying an abdominal compression belt. Blood-ethanol concentration was determined by headspace gas chromatography and breath-ethanol was measured with an electrochemical instrument (Alcolmeter SD-400) or a quantitative infrared analyzer (Data-Master). During the absorption of alcohol, which occurred during the first 90 min after the start of drinking, BrAC (mg/210 L) tended to be the same or higher than venous BAC (mg/dL). In the post-peak phase, the BAC always exceeded BrAC. Four of the 10 subjects definitely experienced gastric reflux during the study although this did not result in widely deviant BrAC readings compared with BAC when sampling occurred at 5-min intervals. We conclude that the risk of alcohol erupting from the stomach into the mouth owing to gastric reflux and falsely increasing the result of an evidential breath-alcohol test is highly improbable.     

Statistical evaluation of standardized field sobriety tests

Standardized Field Sobriety Tests (SFSTs) are used as qualitative indicators of impairment by alcohol in individuals suspected of DUI. Stuster and Burns authored a report on this testing and presented the SFSTs as being 91% accurate in predicting Blood Alcohol Concentration (BAC) as lying at or above 0.08%. Their conclusions regarding accuracy are heavily weighted by the large number of subjects with very high BAC levels. This present study re-analyzes the original data with a more complete statistical evaluation. Our evaluation indicates that the accuracy of the SFSTs depends on the BAC level and is much poorer than that indicated by Stuster and Burns. While the SFSTs may be usable for evaluating suspects for BAC, the means of evaluation must be significantly modified to represent the large degree of variability of BAC in relation to SFST test scores. The tests are likely to be mainly useful in identifying subjects with a BAC substantially greater than 0.08%. Given the moderate to high correlation of the tests with BAC, there is potential for improved application of the test after further development, including a more diverse sample of BAC levels, adjustment of the scoring system and a statistically-based method for using the SFST to predict a BAC greater than 0.08%.     

Evaluation of breath-alcohol instruments. IV. Roadside tests with Alcolmeter pocket model

This paper reports results from a field trial with a breath-alcohol screening device--Alcolmeter pocket model. Breath tests were made with drivers apprehended during routine controls (road-blocks), for traffic violations and those involved in traffic accidents. Of 908 roadside breath tests made with chemical reagent tubes, 343 showed zero alcohol (no colour change) and these results were confirmed by Alcolmeter. Alcohol was detected in 191 tests but the level was judged as being below the legal limit of 0.50 mg/ml. The Alcolmeter results, however, ranged from 0 to 1.22 mg/ml (mean 0.21 mg/ml) and 15 individuals (7.8%) were above the legal limit. There were 373 positive chemical tube breath screening tests whereas in 5 cases (1.3%) Alcolmeter indicated a blood-alcohol level below 0.50 mg/ml. Duplicate determinations with the Alcolmeter device were highly correlated r = 0.93 +/- 0.02 (+/- S.E.), P less than 0.001. The standard deviation of a single breath-alcohol analysis under field conditions was +/- 0.10 mg/ml which corresponds to a coefficient of variation of 10%. The time interval between positive roadside breath test and blood-sampling ranged from 5 to 220 min (median 62 min). The results were therefore adjusted by 0.15 mg/ml per hour to compensate for ethanol metabolised between the time of sampling blood and breath. The corrected blood and breath values were well correlated r = 0.84 +/- 0.03, P less than 0.001 but the predictive power of the regression relationship was poor. The regression equation was y = 0.27 +/- 0.65x and the standard error estimate was +/- 0.21 mg/ml at the mean concentration of ethanol of 1.0 mg/ml.     

Observations on the specificity of breath-alcohol analyzers used for clinical and medicolegal purposes

This paper deals with the application of three kinds of breath-alcohol analyzer for clinical and medicolegal purposes. The limited specificity for analyzing ethanol in expired breath has given misleading information with potential serious consequences. Three different methods of alcohol analysis are reported: semiconductor sensing (Alcotest 7310), electrochemical fuel cell (Alcolmeter SM-1), and infrared (IR) absorptiometry (IR Intoximeter 3000). Methanol could not be distinguished from ethanol with any of these breath-test instruments. When nonspecific techniques of ethanol analysis are used, the results must be considered with caution when interfering substances expelled in breath cannot be excluded.     

An application of probability theory to a group of breath-alcohol and blood-alcohol data

Many jurisdictions have "per se" driving-while-intoxicated (DWI) status expressed in terms of a blood-alcohol concentration (BAC) standard (in grams per 100 mL or the equivalent). Since breath-alcohol (BrAC) analysis is typically employed to determine BAC, there is often challenge to the use of an assumed 2100:1 conversion ratio. This concern may be relevant in light of considerable data that show a low percentage of cases in which BrAC greater than BAC, and this concern increases when the BrAC is used to predict BAC in the context of "per se" legislation. Probability theory provides a basis for estimating the likelihood of an individual having a BrAC greater than or equal to g/210 L with a corresponding BAC less than 0.10 g/100 mL. Actual field data from the state of Wisconsin (n = 404) were evaluated to determine the probability of this occurrence. The probability for this occurrence involves the multiplication law for independent events. The computed probability from the data was 0.018. The actual number of occurrences where BrAC greater than or equal to 0.10 g/210 L and BAC less than 0.10 g/100 mL was 5, resulting in a probability of 0.012. The concern of having BrAC greater than BAC at the critical "per se" level has a very low probability of occurrence, which thus supports the reasonableness of "per se" DWI legislation based upon a blood-alcohol standard determined by breath-alcohol analysis.     

A test of sex determination from measurements of chest radiographs

Sexually dimorphic distinctions within the human thoracic area may include morphological as well as metric differences in the sternum and 4th rib. This research assesses the validity of a set of previously published measurements from chest radiographs and their use in contemporary forensic situations. The chest plates from 130 adult individuals of a known sample undergoing medico-legal post-mortem examination were examined at autopsy. Thoracic radiographs were taken using a Faxitron cabinet X-ray machine at 40 kV using Kodak Diagnostic Film Ready Pack X-Omat TL. Measurements were taken to the nearest millimetre using a sliding calliper. Logistic regression analysis of measurements of the sternum and 4th rib was undertaken to determine sex. Using 4th rib width and sternal area, sex was predicted at an accuracy of 95.8% for males and 90.3% for females.     

Evaluation of breath-alcohol instruments. III. Controlled field trial with Alcolmeter pocket model

A breath-alcohol screening device, Alcolmeter pocket model, was evaluated in a controlled field trial with policeman operating the instruments. The results of tests made with subjects before they drank alcohol were always zero. The standard deviation (S.D.) of breath alcohol determinations increased with increase in the concentration of alcohol in the sample, being 0.036 mg/ml at a mean blood-ethanol concentration of 0.53 mg/ml. The S.D. varied among subjects tested (from 0.022 to 0.053 mg/ml) as well as among the instruments used (from 0.023 to 0.054 mg/ml). The breath test results were on average less than the actual blood-ethanol concentrations when a 2100: 1 blood/breath ratio was used to calibrate the Alcolmeter device. Blood ethanol (x) and Alcolmeter readings (y) were highly correlated (r = 0.95 +/- 0.018) and the regression equation was y = -0.017 + 0.95x. At a mean blood-ethanol concentration of 0.50 mg/ml, the Alcolmeter instrument will indicate 0.46 mg/ml on average. The standard error estimate was 0.085 mg/ml, being 17% of the mean Alcolmeter reading and this corresponds to 95% confidence limits of +/- 0.17 mg/ml. The results of this study show that Alcolmeter pocket-model is a useful device for breath-alcohol screening purposes at a blood-alcohol level of 0.50 mg/ml. A blood/breath ratio of 2300 should be used to calibrate the Alcolmeter device.     

An evaluation of determination of handedness using standard osteological measurements

Numerous studies have assessed side dominance assuming arm bones on the side of handedness will be larger, but concerns over sample size or replicability of measurements usually emerged. Attempting to improve upon these limitations, this investigation analyzes patterns of side difference for standard length and transverse dimensions of the scapula, clavicle, humerus, ulna, and radius for 137 individuals of known handedness. The results showed that with few exceptions, the right side of the skeleton was consistently larger in most individuals regardless of side dominance. Combinations of other measurements previously suggested to be indicative of handedness as well as the use of discriminant analysis also failed to provide reliable estimators. These findings are likely related to the fact that activities of modern individuals are generally not sufficiently unilateral in their stresses to cause asymmetrical development in the arm bones. Therefore, it is recommended that other means be developed to assess side dominance.     

Evaluation of methyl tert-butyl ether (MTBE) as an interference on commercial breath-alcohol analyzers.

Anecdotal reports suggest that high environmental or occupational exposures to the fuel oxygenate methyl tert-butyl ether (MTBE) may result in breath concentrations that are sufficiently elevated to cause a false positive on commercial breath-alcohol analyzers. We evaluated this possibility in vitro by establishing a response curve for simulated breath containing MTBE in ethanol. Two types of breath-alcohol analyzers were evaluated. One analyzer's principle of operation involves in situ wet chemistry (oxidation of ethanol in a potassium dichromate solution) and absorption of visible light. The second instrument uses a combination of infrared absorption and an electrochemical sensor. Both types of instruments are currently used, although the former method represents older technology while the latter method represents newer technology.The percent blood alcohol response curve was evaluated over a breath concentration range thought to be relevant to high-level environmental or occupational exposure (0-361 microg/l). Results indicate that MTBE positively biases the response of the older technology Breathalyzer when evaluated as a single constituent or in combination with ethanol. We conclude that a false positive is possible on this instrument if the MTBE exposure is very high, recent with respect to testing, and occurs in combination with ethanol consumption. The interference can be identified on the older technology instrument by a time dependent post-reading increase in the instrument response that does not occur for ethanol alone. In contrast, the newer technology instrument using infrared and electrochemical detectors did not respond to MTBE at lower levels (0-36 microg/l), and at higher levels (>72 microg/l) the instrument indicated an "interference" or "error". For this instrument, a false positive does not occur even at high MTBE levels in the presence of ethanol.     

Field performance of the Intoxilyzer 5000: a comparison of blood- and breath-alcohol results in Wisconsin drivers

Intoxilyzer 5000 and blood-alcohol results from drivers arrested for operating a motor vehicle while intoxicated and for related offenses were compared during a two-year period. Three hundred and ninety-five pairs of results were studied. The breath- and blood-alcohol specimens in this study were collected within 1 h of each other. The mean blood-alcohol concentration obtained was 0.180 g/dL, with a range from zero to 0.338 g/dL. By comparison, the mean Intoxilyzer 5000 result was 0.16 g/210 L with a range from zero to 0.32 g/210 L. Compared with the blood-alcohol result, Intoxilyzer 5000 results were lower by more than 0.01 g/210 L 67% of the time, within 0.01 g/210 L 31% of the time, and higher by more than 0.01 g/210 L 2% of the time.     

盗窃案件现场检材提取与DNA检测结果的统计分析

目的统计分析1574例盗窃案件中提取的2496个现场生物检材,为提高DNA在盗窃案件侦破中的应用成效提供参考。方法根据2496个生物检材的类型、现场提取方法、重点提取部位、DNA检测结果等进行统计和分析比较,总结常见类型盗窃案件现场生物检材的主要发现提取部位以及不同方法提取的现场生物检材DNA检出率。结果接触类检材已成为盗窃案件最多见的生物检材类型,但检出率仍然较低,对混合分型应进一步分析筛选以提高DNA的认定率;不同方法提取的现场生物检材在DNA检出率方面存在统计学差异,接触类生物检材以植绒拭子和原物提取的方式为首选;现场生物检材的主要发现提取部位根据盗窃案件的类型不同有所侧重。结论现场勘查人员在盗窃案件中发现和提取到有价值的生物检材是提高DNA检出认定能力的关键因素,应着力培养现场勘查人员的微量生物物证意识,提高现场勘查人员提取和处理微量生物检材的能力。     

Breathalyzer accuracy in actual law enforcement practice: a comparison of blood- and breath-alcohol results in Wisconsin drivers

Breathalyzer and blood-alcohol results from drivers arrested for operating a motor vehicle while intoxicated and for related offenses were compared during a two-year period. Four hundred and four pairs of breath- and blood-alcohol results from specimens collected within 1 h of each other were studied. Blood-alcohol concentrations ranged from zero to 0.421% weight per volume (w/v). Breath-alcohol concentrations ranged from zero to 0.44 g/210 L. The mean Breathalyzer result was 0.16 g/210 L. The mean blood-alcohol result was 0.176% w/v. Compared to the blood-alcohol result, Breathalyzer results were lower by more than 0.01 g/210 L 61% of the time, within 0.01 g/210 L 33% of the time, and higher by more than 0.01 g/210 L 6% of the time.     

Determination of stature from skeletal and skull measurements by CT scan evaluation

The aim of this article is to find a correlation between height and femur/skull measurements through Computed Tomography (CT) scans and derive regression equations for total skeletal height estimation in the Caucasian population. We selected 200 Caucasian patients from March 2010 to July 2011 who had to perform a CT scan for cancer restaging. The mean age is 64.5 years. Both sexes are represented by the same number of persons. Patients have executed a total body CT scan with contrast; once scan accomplished, we measured height through a digital scales. We analyzed CT scans of each patient, obtaining multiplanar reconstruction in sagittal and coronal planes with 1mm of thickness, and we measured 10 diameters of skull and femur. Then we performed a single and a multiple regression analysis considering the three diameters that better correlated with height. The skeletal diameters with the highest correlation coefficients with stature were femur lengths, length of cranial base (Ba-N), and distance from the posterior extremity of the cranial base to the inferior point of the nasal bone (Ba-NB). Although both femur and skull are skeletal segments used for stature estimation, in our sample femur gave stronger correlation with height than skull. h=35.7+1.48·BaN+2.32·BaNB+2.53·FEM and h=3.06·FEM+72.6 are the formulae that provided the most accurate stature assessment using multiple and single regression analysis respectively.     

抗人Tf及抗人Hb试剂盒的比较

目的研究比较抗人Tf(转铁蛋白)和抗人Hb(血红蛋白)试剂盒的实验方法。方法采用胶体金标记单克隆抗体结合免疫层析技术,对不同稀释度的人血、动物血进行检测,并对保存时间、溶解度等影响因素进行研究。结果抗人Tf和抗人Hb试剂盒同样具有简单、快速、灵敏、稳定、特异性好的优点,但抗人Tf试剂盒能检测出陈旧及难以溶解血痕。结论抗人Tf试剂盒适用于法医物证的血痕种属检验。     

Statistical evaluation of the evidential value of human hairs possibly coming from multiple sources

A concept of the mathematical evaluation of human hair evidence is derived. This concept can be realized in a special computer program, the output of which is an incrimination probability. The problems of not knowing the true number of sources and the correct partition of hairs corresponding to their sources are solved from the point of view of avoiding an unjustified incrimination.