The Basics of Blood Alcohol Testing by Gas Chromatography – Part II

September 19th, 2014 Allen Trapp Posted in Blood Test, Chemical Test No Comments »

The various solutes travel through the column at different rates. The fastest moving solute exits (elutes) the column first then is followed by the remaining solutes in corresponding order. After the compounds have been eluted from the end of the column, they must be detected, one at a time. As each solute elutes from the column, it enters the heated detector. An electronic signal is generated upon interaction of the solute with the detector. The size of the signal is recorded by a data system and is plotted against elapsed time to produce a chromatogram.

The plot created by this process is called a chromatogram. The size of the signal is proportional to the amount of a compound in the sample. In conjunction with the data recorder, an integrator is frequently used to provide measurements of the height of the compound’s signal and the time that it took for the compound to elute through the column and reach the detector.  While many types of detectors exist, the most common detector used for the blood alcohol analysis is the flame ionization detector. The flame ionization detector simply burns each organic compound as it elutes from the column. As the compound burns, it produces an electrical signal. The electrical signal is displayed as a “peak” with a known retention time. The period of time between injection and reaching the detector is referred to as the retention time.

The retention time of a compound alone is insufficient to identity of compound. The retention time of a known compound must be compared to the retention time of the unknown compound to determine if the known compound also exists in the testing sample. By comparing the retention time of the compound to a known standard, the compound can be identified. Identifying the compound is the qualitative portion of the analysis.

The concentration of alcohol in a sample is measured by comparing the size of the peak produced by the testing sample to the size of the peak produced by different known concentrations of alcohol.   Measurement of the amount of the compound in the sample is the quantitative portion of the analysis.  Each compound has a different retention time with a particular mobile phase, stationary phase, and temperature. If testing conditions change, identifying the compound is not possible. Therefore, the instrument must be periodically tested with a known specimen to ensure the testing conditions have not changed and the calibration of instrument remains intact.

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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The Basics of Blood Alcohol Testing by Gas Chromatography – Part I

September 19th, 2014 Allen Trapp Posted in Blood Test, Chemical Test No Comments »

The first stage of sample testing is the injection of the sample into the injector port. The sample is introduced into the injector port with a syringe or an exterior sampling device known as a pipette. The injector port is a hollow, glass-lined cylinder that is heated to 150-250°C which causes the sample to vaporize.

Most blood alcohol analyses are performed via headspace gas analysis as opposed to direct injection. A small amount (approximately 0.10 milliliters) of blood is diluted with water to about 1.0 milliliter in volume. The sample is placed in a sample vial and the cap is crimped and placed in an auto sampler with an incubating chamber set at a constant temperature. When the sample has reached equilibrium (when the rate of ethanol evaporation equals the rate of condensation in the sample vial), a sample of the gas above the liquid is withdrawn and injected into the gas chromatograph.

At this stage of the analysis Henry’s Law is in effect. Henry’s Law is a chemical principle that describes therelationship of volatile compounds in dilute aqueous solution at equilibrium.  Next, the vapors of the sample are carried into the column by a carrier gas.  The transportation of the vapors by the carrier gas, usually hydrogen, helium, or nitrogen is frequently referred to as the mobile phase. The carrier gas flows into the injector port, through the column, which is maintained by a temperature controlled oven, and then into the detector. The solutes travel through the column at a rate primarily determined by their physical properties, and the temperature and composition of the column. The column is packed or coated. This is commonly referred to as the stationary phase.

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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The Very Basics of Blood Testing

July 21st, 2014 Allen Trapp Posted in Blood Test No Comments »

     A proper blood sample collection must accomplish three things. First, the collection method must protect the integrity of the sample from anything that could change the alcohol concentration of the blood. Second, the method of collection must provide a sufficient quantity of blood for the testing process. Third, the collection process must be medically safe for the subject and for storage. The blood testing kit must not be expired or have contamination.

     In most states, the testing of a suspected impaired driver begins with the blood draw. The suspect is transported to the jail where an on duty nurse secures a sample of the suspect’s blood. The blood can often times be secured by a registered or licensed nurse at a local hospital. Once the blood is secured it should be placed in an area where it can remain stable. The sample should also remain tamper free by methods such as tamper resistant seals or under lock and key by a single evidence custodian. The sample is then transported to the appropriate agency for testing and analysis. In most states, the testing of a suspect’s blood is governed by rules of the state crime laboratory, the Department of Health or the Department of Public Safety. Once the sample reaches the agency, the sample is received by a person who will accept responsibility for the assignment of a case number or other identifying tracking feature. The sample is then placed in storage where it will remain for a period of time prior to testing. Once the testing procedure begins the sample will be placed in an identifying slot where analysis can take place. The testing device and the method used must assure accuracy and reliability by having constant controls, machine calibration and peer review. The results are then reported to the requesting agency. As in standardized field sobriety administration, the failure at any stage to comply with common sense and validated scientific procedure can compromise the validity of the end result.


 

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Quick Look at Continuing Breath Alcohol Test Problems

April 10th, 2014 Allen Trapp Posted in Breath Tests, Chemical Test, Intox 5000 No Comments »

It is now well established that a subject’s manner and mode of breathing just prior to providing breath for analysis can significantly alter the concentration of alcohol in the breath sample.  Hyperventilation has been shown to lower the breath alcohol concentration by as much as 20%.  Holding your breath for a short time (20 seconds) before exhalation increases the alcohol concentration in exhaled air by as much as 15%. Be on the lookout for forced agreement between the two breath samples. An officer can watch the BrAC rise on the second sample. When it gets close to the reading of the first sample, he can tell the subject to stop blowing, to ensure that the two samples are not more than .02 apart.

Since at least 1950 34°C has been the accepted breath temperature used for breath testing purposes. Professor Harger made this decision in 1950 after examining six subjects whose recorded range was between 31°C and 35°C. However in 1996, a much larger study of 700 subjects concluded that the average was 35°C-a full degree higher than Harger’s adopted temperature. Fox & Hayward compared the effects of hyperthermia and hypothermia on breath alcohol results. They found that average increase in Breath Alcohol Concentration over Blood Alcohol Concentration was 8.6°C for each degree Celsius increase in deep-core body temperature.

These are just two of the more basic issues we encounter in DUI defense. Although some lawyers think “anyone can do DUI,” the odds are that those lawyers are not familiar with these issues and will not invest the work required to gain the knowledge. No matter where you are, if you interview a lawyer and he or she cannot discuss these matters, keep looking.

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Roadside Saliva Tests for Drugs- Coming Soon

April 9th, 2014 Allen Trapp Posted in Chemical Test, Driving under the Influence of Drugs No Comments »

The Federal Government is stepping up its focus on drugged driving and the use of roadside tests of saliva to screen for drugs. The Office of National Drug Control Policy working with the Department of Transportation have taken steps to address drugged driving, and several studies have been published. The National Roadside Survey of Alcohol and Drug Use by Drivers, published in 2007, concluded that about one in eight nighttime drivers on the weekend tested positive for illicit drugs.

Drug Testing and Drug-involved Driving of Fatally Injured Drivers in the United States: 2005-2009, found that roughly one in four of fatally injured drivers who tested positive for drugs were under the age of 25.  In 2009, narcotics and cannabinoids accounted for almost half of all positive results. In that same year, eighteen percent of all fatally injured drivers’ nationwide tested positive for drugs at the time of the crash. In addition, The Institute for Behavior and Health published Drugged Driving Research: A White Paper. That paper concluded that drugged driving was a significant domestic and international problem.

Also, there are many drugs with potential impairing effects being prescribed at a rate higher than at any time in our history. The number of narcotic analgesics (e.g., hydrocodone, oxycodone) prescribed over the past decade has skyrocketed. Part of his increase is attributable to an aging population, but many of these drugs find their way into the hands of younger drivers.

Accordingly, drug impaired driving has been thrust into the spotlight of law enforcement, talk show hosts, and lobbyists. Moreover, federal agencies under the name “National Drug Control Strategy” announced their goal is not only to reduce drugged driving by ten percent by 2015, but also to put the prevention of drugged driving on the same level with drunk driving prevention. Included in their strategy was the development of “standard screening methodologies for drukg testing labs to use in detecting the presence of drugs.” This means the roadside saliva tests for drugs, which are already in use in 14 states, will be coming to a roadway near you soon.

 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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More on Hospital Blood Tests for Alcohol

April 5th, 2014 Allen Trapp Posted in Blood Test No Comments »

In an enzymatic test, the type customarily performed when a patient is brought into the emergency room at a hospital, the analysis for alcohol concentration is typically performed on serum or plasma samples, so it is important that you do not assume that the test was performed on whole blood. To measure the alcohol concentration through an enzymatic assay test, the serum or plasma is combined with an enzyme, alcohol dehydrogenase, to form acetaldehyde. Coincidentally, acetaldehyde is the first and most important metabolite of ethyl alcohol.

During this process, nicotinamide adenine dinucleotide (NAD) is converted to NADH. The concentration of NADH is measured to determine the alcohol concentration. Plasma and serum are quite different and have different water content levels. Because alcohol distributes to the different components of the blood according to the water content, the relative water content level of plasma and serum is an important consideration.

Plasma and serum have nearly the same ratio of water to blood and should produce similar alcohol concentrations. The ratio of serum to whole blood varies widely, with at least one study showing the ifference can be as great as 49%. However, a statistical average of about 1.18 seems to be indicated.

The serum or plasma alcohol test is indirect. The amount of NADH, which is an enzyme, is measured spectroscopically at the 340 nanometer wavelength. The amount of NADH present is supposed to be proportionate to the amount of alcohol converted by ADH to acetaldehyde. However, when lactic acid is produced due to stress on muscles resulting from an injury or when ringers lactate is administered by paramedics, LAD will also react with ADH and be read as ethyl alcohol by the enzymatic tests.

In most cases these hospital reports will have “Not for Legal Purposes” written or stamped across the front. However, do not be surprised if zealous prosecutors attempt to use them, and at least in Georgia, they will usually be admissible. Therefore, defense counsel must be prepared to deal with them.


Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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New Breath Testing Device, Intoxilyzer 9000, Coming to Georgia

December 14th, 2013 Allen Trapp Posted in Breath Tests, Chemical Test No Comments »

     Between now and the end of 2015 every Intoxilyzer 5000 in Georgia will be replaced by the Intoxilyzer 9000.  The Division of Forensic Sciences claims the new breath testing instrument is very accurate; however, the handful of “experiments” done during the evaluation period does not support DOFS claims. Their initial experiment on February 15, 2012, was limited to three drinking subjects who were tested at different time intervals and asked to provide both a “minimum exhalation” (instructed to stop blowing when the delivered sample volume was between 1.1 and 1.5 liters) and a “maximum exhalation” (blow, blow, blow). The only female subject was tested 15 minutes after her last drink, and her results were .063 and .073. One of the young male subjects, tested at 30 minutes after he stopped drinking, registered .042 and .045. The last young man, tested 24 minutes after his last drink, blew a .056 followed by a .064. Clearly, neither the first nor the last subject’s test results were within 5 percent of the mean. DOFS seems to have ignored their own requirements, but these results certainly justify encouraging subjects to blow until they cannot blow any longer if your objective is to obtain convictions.

Unlike the Intoxilyzer 5000-EN the new device will print a breath volume for each test. When the 5000-EN was first delivered to DOFS in 1998, it did the same. However, Jim Panter, head of the Implied Consent section at the time, ordered that this capability be disengaged when a person provided an adequate sample because it was “confusing.” Therefore, the 5000-EN only printed a breath volume (in theory) when it reported an insufficient sample. The 9000, as currently configured, will print a breath volume for all cases. The Operator’s Manual instructs officers to encourage subjects to provide a maximum exhalation, because “the longer you blow, the higher you go.

The Division of Forensic Sciences maintains that a person’s breath alcohol concentration is ultimately the product of a continual exchange of ethanol between the blood and breath that occurs in the pulmonary alveoli. DOFS acknowledges that some (“a substantial amount of”) alcohol can be lost to the cooler airway surfaces as the breath moves through the respiratory tract. What they do not acknowledge is the work of Dr. Michael Hlastala, which establishes the alcohol is also “picked up” as a breath sample travels up the respiratory system. He has also demonstrated that true alveolar air cannot be obtained, contrary to assumptions made by chemists sixty years ago, but those assumptions continue to dominate the world of breath alcohol testing.

      Another crucial area examined by DOFS during the evaluation phase was the potential for other volatile organic chemicals to interfere with test results. Few of the experiments were conducted when ethanol was present along with the other chemical. Nevertheless, there some notable findings. Acetaldehyde did not trigger an interferent message until it was present in a concentration of .06g/dl. However, at a concentration of .05, it generated a BrAC of .007.  Acetone did not generate a BrAC reading but was also not detected as an interferent until it was present in a concentration .10g/ml. Other substances such as ethylacetate, toluene, and isobutanol triggered error messages in concentrations as law a .01, while methanol was detected at .02. On the other hand, MEK did not trigger either a reading or an error message at concentrations lower than .10g / ml, once again in the absence of alcohol. Methylene chloride did not produce a reading or an error message at levels up to and including .10g/ml. 

       A number of other experiments were performed. One that caught our attention was the linear range test conducted on February 10, 2012. With a Guth simulator solution heated to 33.9 degrees Celsius, twenty tests were conducted, with an expected value of .08. Only two returned readings under 08, six readings were exactly at .08, and twelve were in excess of .08. Since this machine, like every CMI product on the market, assumes a breath temperature of 34 degrees, these results could be invaluable for a breath temperature defense at low readings. As an aside, the limit of detection shown by the one experiment shows that the lowest number detected was a .013, which was reported as .010.

       A number of states (e.g., South Carolina, Oklahoma) have been downloading breath test data to a central repository for years. DOFS has insisted that the handwritten logs maintained by the individual departments was sufficient, despite obvious omissions a number of us have encountered. One of the criteria for approval of the new Georgia breath testing device was the capability of the device to download data. The Georgia Breath Test Transition Implementation Plan dated June 15, 2012, states that the Division of Forensic Sciences will obtain the COBRA instrument database system for data retrieval from field instruments and seat licenses for each of the Area Supervisors. How this database will be employed remains to be seen, but if done properly it will enable us to detect ongoing problems with particular machines that are currently very difficult to identify. We do know that all Intoxilyzer 9000’s must be connected to the DOFS network through a LAN or data connection by July, 2015. Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

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Warrantless Blood Draws: Supreme Court Has Doubts.

April 18th, 2013 Allen Trapp Posted in Blood Test, Case Law Update No Comments »

Just this week the U.S. Supreme Court decided the case of Missouri v. McNeely.  The Court held that the mere passage of time (resulting in the metabolism of alcohol) did not justify a warrantless blood draw.  The Court did not outlaw all non-consensual warrantless blood testing in DUI cases, but they should now be rare across the country.  The Court disagreed with the State of Missouri, which argued that the passage of time created an “exigency” which justified the failure to obtain a warrant.  Georgia law did not purport to allow forced blood testing without a warrant, but some aspects of our implied consent law may now be called into question. 
Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

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At Least One Court Insists on Valid Blood Tests

April 18th, 2013 Allen Trapp Posted in Blood Test, Case Law Update No Comments »

Hunter v. State, 55 A.3d 360. Del. Supr., (2012).

The Supreme Court of Delaware found that the admission of a test result that was not in compliance with the manufacturer’s requirements.? Furthermore, this error jeopardized the fairness of the trial.? Specifically in this case, using the expired vacutainer tubes in the blood test kit was in direct contravention of the manufacturer’s specification sheet for the vacutainer tubes. The same was true of shaking the tubes vigorously, which was also in direct violation of the manufacturer’s instructions for use of the kit.
Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

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Acetone in Blood Alcohol Tests

February 4th, 2011 Allen Trapp Posted in Blood Test, Chemical Test No Comments »

     Something we are seeing more frequently in gas chromatograms, the charts that show how much of certain substances were found in a person’s blood by the state crime lab, is the presence of acetone.  Sometimes, the crime lab actually reports the amount of acetone in their two-page summary, which is all that most prosecutors or defense attorneys ever see, but more often than not they don’t.  We have also seen a number of tests with isopropyl alcohol present in the blood.

When acetone and isopropyl alcohol are present, it means that the person is probably an uncontrolled diabetic.  Acetone alone is also indicative of this problem.  So what impact does diabetes have on a blood test?  It means that the person has an elvated glucose (sugar) level in the blood, and that sugar with just a little help from an organism known as candida albicans will be fermented into alcohol.  In other words, the sugar in the blood of an uncontrolled (and sometimes undiagnosed) diabetic will be converted to alcohol, which will result in an erroneously high result.  This is particularly true if the blood is not refrigerated, which it never is while it spends three to four days in transit to the crime lab.  The blood alcohol level reported will not be adjusted to reflect the increase in the amount of ethyl alcohol in the blood caused by the endogenous production of alcohol.

The bottom line is that innocent people will be convicted.  An attorney who knows what to look for and a highly qualified forensic toxicologist who knows how to find it are your best protection.
Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

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Blood Alcohol Tests: The Hematocrit Conundrum

October 8th, 2009 Allen Trapp Posted in Blood Test, Chemical Test 1 Comment »

     Whole blood is comprised of red and white blood cells, platelets and other clotting and cellular material, dissolved salts, amino acids, fats, and water.  Those solid materials are frequently referred to as “hematocrit.”  The hematocrit level is, therefore, the percentage of the total volume of blood taken up by the solid particles.  Determining a person’s hematocrit level at the time the blood is drawn is the only way to know what the correct conversion ratio is for the person who was tested at the time of the blood alcohol test.

     The average hematocrit for men is 47% with a “normal” range between 42% and 52%.  The average for women is 42% with a range from 37% to 47%.  Studies have shown, however, that over time an individual’s hematocrit can vary by up to 15%. 

     In general, the higher the hematocrit level, the higher the reported blood alcohol concentration in a serum or plasma test, which is the kind most frequently encountered in a hospital setting.  The higher someone’s hematocrit level, the less liquid we can expect to find in their blood.  Since the alcohol will migrate or remain with the liquid portion of the blood, a person with a higher hematocrit will have a higher blood alcohol test result when that blood alcohol test is a plasma or serum test performed in a hospital. 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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More on Breath Temperature

July 24th, 2009 Allen Trapp Posted in Breath Tests, Intox 5000 No Comments »

     As far back as the 1930’s it was recognized that re-eqilibration of the alcohol and breath occurs at the lower temperature (as opposed to core body temperature) of the upper respiratory tract during expiration in such a manner that temperature controls the alcohol content of the expired alveolar air.  In the earliest “drunk-o-meter” invented by Professor Rolla Harger of Indiana University it was assumed that 61.5% of the collected breath sample was alveolar air and that 2100:1 was the appropriate partition ratio.  Partition ratio in this instance refers to the amount of alcohol in the blood compared to the amount in the breath.

     During a twenty-year period he and his colleagues conducted numerous experiments, which confirmed that the partition ratio varies at different temperatures.  In other words, breath alcohol test results will be different at different temperatures.  During all of this testing it was assumed that the average expired breath temperature was 34 degrees centigrade (Celsius), which in turn led to the conclusion that the average blood:breath partition ratio for breath alcohol testing is 2100:1.  The National Safety Council adopted this number in 1952, and so it has become engraved in the statutes of the several states over the last half century. 

     Researchers have questioned the use of a constant breath temperature and partition ratio since at least 1975.  Beginning in that year leader experts in the field began to question whether airway alcohol exchange played a bigger role in breath alcohol testing than was previously recognized.  More and more research has proven that the average expired breath temperature is closer to 35 degrees Celsius, including the German study of 1995 and a similar study sponsored by the Alabama Department of Public Safety three years later.

     As a result of the Alabama study that state adopted the Draeger 7110, which makes an adjustment for an elevated breath temperature.  In fact, the Alabama testing sequence includes two breath samples (like Georgia), two methods of analysis for every breath test, specifically infrared and fuel cell (unlike Georgia), breath temperature monitoring and correction for each breath test (unlike Georgia), and two calibration checks at .02 and .08 at the time of each breath test (unlike Georgia).  In addition, a comprehensive data collection package including breath exhalation profiles was included in the software designed for Alabama DPS (unlike Georgia).  The downloaded data includes a total review of all breath tests in the State (unlike Georgia).   This enables the state to identify and address both instrumental and operational problems.  In Georgia there is a handwritten log on which officers may make entries, but nobody knows how often it is used or how often it is ignored. 

     The Alabama program is truly a model program other states should emulate.  Before switching to the Draeger, Alabama (like Georgia) used the Inoxilyzer 5000.  That makes me wonder: If it’s not good enough for Alabama, why are we still using it?

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Linearity in Blood Alcohol Testing

June 28th, 2009 Allen Trapp Posted in Blood Test, Chemical Test No Comments »

     Linearity is determined by testing known samples of various concentrations, which should ensure that the tests of other samples of unknown concentrations should yield accurate results.  Linearity enables an analyst to have confidence in the results of a particular test based on the results of other tests.  For example, if a known alcohol concentration of .10 is determined to be .10 and a known concentration of .20 is determined to be .20, this greatly increases the likelihood that a blood alcohol reading of .15 is accurate.

     In most cases the linearity of a gas chromatograph is checked at the beginning of each set of tests (a “run”) by injecting calibrators of varying amounts in the GC.  By plotting the amount of each calibrator versus their relative instrument responses, a linear relationship may be established.  The concept of linearity is associated with the “range” of the instrument, which is the interval between the highest and lowest concentrations that have been determined to be not only linear but accurate and precise.  Accuracy means that the testing device has correctly determined the true result, while precision is the ability of the instrument to replicate the test result.  Therefore, even if a blood alcohol test is “precise,” that merely means that the testing instrument has printed the same result more than once.   As defense attorneys we concentrate on accuracy – whether it can be proven that a blood alcohol test result has determined the correct result.

     It is generally agreed that good laboratory practice requires the use of six calibrators spanning the range of 50 to 150% of the expected range of results the analyst expects to encounter in typical cases.   In other words, the concentration of the calibrators should be such that they bracket the anticipated concentration of the specimen.   The Laboratory Guidelines of the Society of Forensic Toxicologists recommends “at least three calibrators.”  If any result exceeds the range, the substance being tested should be diluted and retested.  If the concentration of the specimen is less than that of the lowest calibrator, in most cases an additional calibrator below the expected range of the analyte in the sample should be set up. 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Blood Tests: The Differences Between Whole Blood, Serum, and Plasma

May 1st, 2009 Allen Trapp Posted in Blood Test, Chemical Test No Comments »

     If there is no anti-clotting agent in a tube used to collect blood, the blood will clot (due to the presence of fibrinogen in the blood). Upon centrifugation of the tube, the clear yellow liquid at the top is called serum and contains little or no fibrinogen because the fibrinogen has been used up in the clotting of the blood cells. A sample of the serum can then be removed for analysis of its serum alcohol concentration.

     If there is an anti-clotting agent in the tube, the blood should not clot if properly mixed (tube inverted a few times). The tube can then be either shaken and a sample of the whole blood can be then be removed for analysis of its blood alcohol concentration, or the tube can be centrifuged. Upon centrifugation of the tube, the clear yellow liquid at the top is call plasma and contains about 0.34 grams of fibrinogen per 100 mL of plasma. A sample of the plasma can then be removed for analysis of its plasma alcohol concentration.

     Because serum and plasma only differ by the absence or the presence of a trace amount of the fibrinogen protein, the serum alcohol concentration and the plasma alcohol concentration should be essentially identical. However, due to their higher water content than whole blood, the alcohol concentration in either serum or plasma should be about 18% greater on average than the actual whole blood alcohol concentration.No forensic testing laboratory would try to measure the alcohol concentration in a blood clot which, because of its relatively low water content, would be relatively low in alcohol concentration compared to the whole blood alcohol concentration.

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Blood Alcohol Tests: Collecting the Blood

March 23rd, 2009 Allen Trapp Posted in Blood Test, Chemical Test 1 Comment »

     The first step in the blood collection process is decontamination of the area where the blood will be drawn.  In clinical use a prepackaged 70% isopropyl alcohol pad is the preferred antiseptic.  However, Betadine (povidone-iodine) is the swab of choice for forensic blood draws.  If Betadine is used, it must be allowed to dry prior to the puncture.  Studies have shown that sloppy swabbing of an injection site will increase a blood alcohol concentration.

     Most forensic laboratories purchase 10 milliliter gray top tubes containing 100 mg. sodium floride, a preservative, and 20 mg. potassium oxalate, an anti-coagulant.  Therefore, when 10 ml. of blood is drawn, the concentration of preservative is one percent.  A tube with an anti-coagulant should be inverted at least eight times (eight to ten is usually recommended).  If this is not done, the anti-coagulant will not properly mix, resulting in a low concentration, which in turn can lead to microclotting and an inaccurate result.  This is not just the wishful thinking of a defense attorney but is included in the instructions issued by the manufacturer of the blood alcohol collection tubes used in Georgia. 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website

    

   

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Urine Testing: The Basics

March 19th, 2009 Allen Trapp Posted in Driving under the Influence of Drugs, Urine Test No Comments »

     Urine samples are usually tested for drugs by using a screening test followed by gas chromatography-mass spectroscopy (GCMS).  The screening test is normally an enzymatic method of analysis that determines if the “signal strength” is at or above a cut-off level.  These tests employ reagents that interact with several different but related compounds (e.g., metabolites) and measure the total “signal strength” of all those compounds. 

     GCMS should be able to identify both the parent drug and any metabolite(s).  If a parent drug is identified, the metabolite should also be present.  For example, if a urine sample is positive for methamphetamine, it should also be positive for amphetamine. 

     In order for a test result to be reported as positive the amount of a compound should equal or exceed the cut-off level.  If the cut-off limit for the GCMS is not met, the result should be reported as negative.   In other words, sound science dictates that reports reading “lower than the lowest calibrator” should not be reported as positive.

     One final word about metabolites: Most metabolites are less psychoactive than the parent drug or are inactive, which means that they have no impact on the person.  If only an inactive metabolite such as carboxy THC is found in a urine sample, the metabolite did not affect driving. 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Combined Influence of Alcohol and Drugs

March 19th, 2009 Allen Trapp Posted in Blood Test, Chemical Test, Driving under the Influence of Drugs No Comments »

     We are seeing more arrests for DUI where the breath alcohol concentration is not consistent with the manifestations of impairment described in the arrest report or captured on video.  In some, but not all of these cases, the culprit is detected by a blood test, and that culprit is some drug other than alcohol that the client has consumed.  As more and more people take selective serotonin reuptake inhibitors (SSRI’s) such as Paxil and Prozac, we will see more and more of these cases.

     Alcohol and many drugs do not simply have an additive effect; they have a synergistic effect.  That is to say that the effects of the two substances are not merely added together but are essentially multiplied.  When even an adult dose of acetaminophen may produce impairment equivalent to a BAC of .05, it is not difficult to understand how prescription medications combined with alcohol can cause serious impairment. 

     One of the other commonly abused drugs is oxycodone.  It is the narcotic found in Percoset (with acetaminophen) and Percodan (with aspirin).  It is a synthetic opioid and like its natural cousins can cause addiction and then withdrawal symptoms. 

     When we represent an individual with these drugs in his or her system at the time of arrest, it is almost always necessary to retain a pharmacologist or toxicologist.  Otherwise, an employee of the state crime lab will be the only “expert” in the courtroom, and that employee’s testimony, if unrefuted, will seal the defendant’s fate. 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Does the Breath Test Really Measure Deep Lung Air?

March 11th, 2009 Allen Trapp Posted in Breath Tests, Chemical Test, Intox 5000 No Comments »

     One of the assumptions upon which breath alcohol testing has rested since the 1950’s is the belief that the instruments measure “deep lung” or alveolar air.  This outdated assumption has been eroded as research over the past two decades has yielded a greater understanding of the exchange of highly soluble gases by the lungs.  No longer can it be assumed that alveolar air is in equilibrium with blood alcohol simply because the breath test reading reaches a plateau. 

     The findings of Dr. Michael Hlastala of the University of Washington confirm that during inspiration the relatively cool and dry air being inhaled becomes warmer and absorbs liquid in the airways.  This air also absorbs soluble gas dissolved in the airway tissue.  During exhalation the air is cooled and dehumified.   The alcohol present in a breath sample comes entirely from the lining of the airways.  This mucus and tissue, not the blood in the lower part of the lungs, is the source of “breath alcohol concentrations.”

     Further research has shown that breath alcohol concentration continues to rise as a person exhales until he or she cannot exhale any longer, which causes the flattening or plateau of the breath alcohol concentration.   It has also been confirmed that the average directly measured partition coefficient for alcohol in blood at 98.6 degrees Fahrenheit is 1756:1, not  2100:1 as asssumed by the Intoxilyzer 5000.   Also of significance is the discovery that an increase in exhaled volume beyond the minimum required by a breath testing instrument results in an increased breath alcohol reading and a decreased blood to breath partition ratio.  For those with smaller lung capacity, these findings also have negative consequences because a greater portion of their vital capacity (maximum volume of air that can be inhaled and exhaled) is necessary in order to generate a printed result.  On the other hand, those with larger lungs will benefit from an unfair advantage. 

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Alcohol is not Always Ethanol

March 11th, 2009 Allen Trapp Posted in Breath Tests, Chemical Test, Intox 5000 1 Comment »

     Ethanol or ethyl alcohol contains two carbon atoms linked to hydrogen atoms (methyl groups) and one oxygen atom linked to a hydrogen atom (hydroxyl group).  Most infrared breath testing devices rely upon the absorption of light at the 3.39 and 3.48 micron wavelengths, which are characteristic of the carbon-hydrogen bond,  for the determination of breath alcohol concentration.   However, at these wavelengths the infrared energy will be absorbed by many organic molecules containing carbon atoms bonded to hydrogen atoms, including hexane, toluene, and methyl ethyl ketone. 

     Experiments have shown that the Intoxilyzer 5000 will report these substances as ethyl alcohol and will print what purports to be a breath alcohol concentration.  In other words, the results for substances other than ethyl alcohol are reported as alcohol.  The research leaves little doubt that the instrument simply cannot distinguish the different alcohols from each other.   The numerical results are always reported as grams of alcohol per 210 liters of breath even when there is no ethanol in the breath sample.  

     The results for these interfering substances once again demonstrate the non-specificity of the Intoxilyzer 5000 and any other breath analyzer that relies on the the absorption of energy by the carbon-hydrogen bond in the 3.39 and 3.48 micron range.   

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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Infrared Breath Testing Devices: Common Problems

October 21st, 2008 Allen Trapp Posted in Breath Tests, Chemical Test, Intox 5000 No Comments »

     A major issue with infrared breath testing devices is that they not only detect the ethyl alcohol found in alcoholic beverages but also in other substances that have a similar molecular structure. Stated differently, these devices identify any compound containing the methyl group molecular structure. And the issue with this is that more than one hundred compounds can be found in a human’s breath at any one time and 70% to 80% of these compounds contain the methyl group molecular structure. The consequence of this is that these methyl group molecular structures will be incorrectly identified and labeled as ethyl alcohol. Interestingly, the more ethyl group substances the breathalyzer detects, the higher the false blood alcohol content estimate will be.

     The National Highway Traffic Safety Administration (NHTSA) has found that people who are diabetics or dieters can have acetone levels that are hundreds, if not a thousand of times higher than people who are not diabetics or dieters. The key issue here is that acetone is one of the many substances that can be falsely detected as ethyl alcohol by some breathalyzers.

     There’s also a variety of products found in the environment that can lead to erroneous BAC results with these machines. Some of these products include substances or compounds found in cleaning fluids, celluloid, gasoline, paint removers, and in lacquers. Other common substances that can result in false BAC levels are alcohol, vomit, or blood in the person’s mouth. False BAC readings can also be caused from electrical interference, dirt, smoke, cell phones, police radios, moisture, and tobacco smoke.

     Infrared breath testing devices can be very sensitive to temperature and will result in false readings if they are not adjusted or recalibrated to compensate for ambient or surrounding air temperatures. Moreover, the temperature of the person being tested is also significant. More specifically, each degree (in Centigrade) in the subject’s body temperature above 34 C (98.6 Fahrenheit)  can result in a relatively large elevation (about 8.6%) in apparent BAC.

Written by Allen Trapp who is board certified by the National College for DUI Defense and the author of Georgia DUI Survival Guide Visit Website
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