| There are several different methods available for | | | | by slight finger pressure on the outer flexible clear |
| alcohol testing. Alcohol can be tested in the blood, | | | | tube to release crystals within the confines of the |
| breath, urine and saliva. | | | | tube. When the subject exhales into the tube, |
| Blood Alcohol Testing | | | | crystals interact with breath vapor and change |
| Blood Alcohol Concentration (BAC) is considered | | | | color from yellow to blue if alcohol is present. If all |
| to be the standard for measuring the degree to | | | | the crystals change color completely, this indicates |
| which an individual is impaired by alcohol. For | | | | that the blood alcohol level of the subject is over |
| years, studies have shown that there is a direct | | | | 0.10%, exceeding the legal limit in most states. |
| correlation between the blood alcohol | | | | Urine Alcohol Testing |
| concentration and the degree to which reactions | | | | Although urine alcohol testing will indicate the |
| and judgments are impaired. The methodology | | | | presence of alcohol of a person, it will not indicate |
| used for blood alcohol testing is Gas | | | | the current condition of the individual. Once |
| Chromatography and is the most accurate | | | | consumed, alcohol enters the blood through the |
| forensic quality test in the industry today. | | | | stomach within 15 minutes, causing immediate |
| However, drawing blood is an invasive and | | | | impairment. It is then metabolized by the body |
| expensive procedure that most companies prefer | | | | and, after 1½ to 2 hours, will begin to show |
| to avoid. | | | | up in the urine. Therefore, urine alcohol does not |
| Breath Alcohol Testing | | | | measure a true condition of the person. The |
| It is well proven that there is a direct correlation | | | | results indicate the condition several hours before. |
| between the blood alcohol concentration of a | | | | Additionally, urine alcohol concentration does not |
| person and their breath alcohol contents. During | | | | directly correspond to blood alcohol concentration. |
| respiration, gas is exchanged from the lungs to | | | | Urine alcohol concentration will vary depending on |
| the blood (primarily oxygen) during inhalation, and | | | | the metabolism of the person and the amount of |
| visa versa (primarily C02) during exhalation. During | | | | fluid in his system. For instance, a person who is |
| this exchange, alcohol in the blood vaporizes and is | | | | slightly dehydrated will tend to have a higher |
| carried out of the lungs in the exhaled breath. | | | | alcohol concentration in his urine than someone |
| There are several types of breath alcohol testers | | | | who has a normal level of fluid in his system. |
| available today. These range from disposable | | | | At least one study has indicated that a false |
| screening testers to the equipment that provides | | | | positive for urine alcohol can occur. High levels of |
| legally admissible results, including very expensive | | | | sugar and acetone in the body can cause |
| digital read-out breath alcohol monitors. These | | | | fermentation in the urine, creating a false positive |
| types of testers fall into three categories: | | | | for urine alcohol. All things considered, the urine |
| - Evidential Breath Testing Devices | | | | alcohol test is the least preferred or perhaps |
| - Non Evidential Portable Hand Held Devices | | | | accurate test available for alcohol testing. It is |
| - Disposable Devices (provides non forensic | | | | worthwhile to read a supporting research paper |
| results) | | | | published in THE AMERICAN JOURNAL OF |
| The evidential breath testing devices are generally | | | | CLINICAL PATHOLOGY: ERRORS OF |
| expensive (costs range from $2000-$5000 per | | | | CONVERTING A URINE ALCOHOL VALUE INTO |
| unit), require regular maintenance, repair and | | | | A BLOOD ALCOHOL LEVEL. SIDNEY KAYE, PH.D., |
| calibration, and must be operated by certified | | | | AND EDUARDO CARDONA, M. S. |
| personnel. Attachments such as sterile mouth | | | | Saliva Alcohol Testing |
| pieces must be used each time a test is | | | | The second type of disposable tester available |
| performed. These units are large table top units | | | | today tests the saliva for alcohol presence. |
| designed to be used in one location. Movement | | | | Although a correlation between blood alcohol |
| can cause a change in calibration which will require | | | | concentration and saliva alcohol concentration is |
| maintenance. | | | | believed to exist, the technology and chemical |
| The portable hand held devices provide fairly | | | | reaction employed has not been proven to be |
| accurate results and are used for screening | | | | accurate or reliable. |
| purposes. By measuring the alcohol content in the | | | | Saliva testers are treated with an enzyme Alcohol |
| breath, a reliable indication of the blood alcohol | | | | Oxidize, which responds to alcohol in proportion to |
| level is achieved. Portables devices are less | | | | the concentration of alcohol in a mixed saliva |
| accurate than evidential devices, however by | | | | sample placed on it. The user estimates the BAC |
| comparing the cost performance ratio, these | | | | by comparing the color change on the test strip |
| devices are affordable and sufficient for personal | | | | patch to standard colors calibrated to correspond |
| usage. Most potable devices are not evidential and | | | | to different BACs. |
| therefore they cannot be used in the court of | | | | Although some saliva testers seem to indicate the |
| law. | | | | presence of alcohol fairly well, the enzyme alcohol |
| The disposable devices are noninvasive, less | | | | oxidize used in these testers is easily effected by |
| accurate and non scalable methods of screening | | | | hot and cold temperatures. Hot temperatures will |
| for alcohol. Can be used to detect the presence | | | | tend to indicate falsely high readings, while cold |
| of alcohol with a rough estimate to the degree of | | | | temperatures will tend to indicate falsely low |
| impairment. Being disposable, the cost per test for | | | | readings. Exposure to temperatures above 80 |
| preliminary screening is considerably higher than | | | | degrees Fahrenheit or to ambient air will destroy |
| the cost of testing using portable devices. | | | | the enzyme alcohol oxidize rendering the tester |
| Here is how they work The ethyl alcohol in the | | | | useless. Most saliva testers give no indication if |
| blood escapes through the lung tissue into the | | | | contamination has occurred, they just will not |
| exhaled breath. The presence of ethyl alcohol in | | | | work. Saliva testers generally have a shelf life of |
| the breath is detectable by a color change of | | | | one year or less. |
| very sensitive chemically coated crystals | | | | Additionally, most saliva testers do not have test |
| contained in the Disposable Breath Analyzer. | | | | results from independent laboratories. |
| Immediately prior to use, the ampoule is ruptured | | | | |