Inherent Error Rate In Blood and Breath Alcohol Testing

Even if you assume that maintenance and calibration of the breath machine is perfect, the breath or blood test is administered exactly according to procedure, and no background or physiological factors exist that would produce false results. An inherent error still exists as to both blood alcohol testing procedures. Most experts agree the inherent error rate is about +/- .02% for DUI breath testing and +/- .01% for DUI blood testing. Any breath or blood result should be reported with a margin of error.  For example, a breath test should read 0.08% +/- 0.02%.  this means you can be as high as a 0.10% or as low as 0.06%.  Scientifically, that’s as good as the government’s breath testing results get and that is why many innocent people plead guilty to DUI because they are unaware of these problems with the government’s tests.

Rising Blood Alcohol Level

To be guilty of DUI, you have to have a blood alcohol concentration over 0.08% at the time of driving. If your blood alcohol concentration is rising when you are given the chemical test, you may have been under the legal limit at the time of driving. For example, you could blow a 0.11% at the police station but be 0.07% BAC when you got pulled over. Why? Because your blood alcohol level can increase by 0.02% or more an hour.  If 2 hours pass from the time you are stopped until the time you are given a chemical test, you could easily rise from 0.07% to 0.11% BAC.  Alcohol takes as long as three hours or more to fully absorb into your bloodstream and create your peak blood alcohol level. This is critical if the DUI traffic stop occurred relatively soon after you finished drinking. You can see that even if your BAC was above .08% when the blood draw or breath test occurred at the police station (or hospital), it may well have been below .08% when you were actually driving. There is no law against having a BAC above .08% at a police station; it’s only the blood alcohol level while actually driving that counts for DUI purposes.

Title 17 Regulations – Breath/Blood Testing Requirements 

California Code of Regulations Title 17 sets forth procedures that must be followed by the government when they collect breath and blood samples.  State law requires that breath and blood tests follow strict procedures because of the high potential for inaccurate test results when proper procedures are not followed.  If the government can’t prove beyond a reasonable doubt that they complied with State law, you can win because the forensic evidence is compromised.

Title 17 Regulations – 15 minute Observation period   

The law requires that a person given a breath test be placed under continuous observation for at least fifteen minutes prior to collection of the breath sample.  (CCR Title 17, Sec. 1219.3).  The 15-minute observation period is required for 2 reasons, to make sure there is no mouth alcohol to contaminate the breath sample, and to make sure the person has not ingested alcoholic beverages or other fluids, regurgitated, vomited, eaten, or smoked which could also contaminate the breath sample.  In most DUI cases, the first breath test given by the side of the road is given before 15 minutes has elapsed making its results suspect. In other cases, people will smoke, have gum, or chew tobacco during the 15-minute observation period.  This violates the legal requirements for breath testing and requires a new 15-minute observation to begin upon removal of the foreign substance.  Finally, many officers do not continuously monitor the person for the 15-minute observation period because they are busy doing their DUI investigation and paperwork. If the government can’t prove beyond a reasonable doubt that they complied with the 15-minute observation period, you can win because the forensic evidence is compromised.

Title 17 Regulations – Accuracy checks    

On all breath devices used in California there must be periodic accuracy checks conducted every 10 days or 150 tests, whichever comes first.  In many cases, the accuracy checks are out of compliance resulting in unreliable test results.  It’s important to check the accuracy check records in every case.  If the government can’t prove beyond a reasonable doubt that they complied with the required accuracy checks, you can win because the forensic evidence is compromised.

Title 17 Regulations – Blood Testing

A DUI blood sample must be taken from a vein and not an artery, and only authorized persons are allowed to take a forensic blood draw (CCR Title 17, Sec.1219.1(a)); no alcohol or other volatile organic disinfectant shall be used to clean the skin where a specimen is collected, only aqueous benzalkonium chloride (Zephiran), aqueous merthiolate or other suitable aqueous disinfectant shall be used (CCR Title 17, Sec.1219.1(c)); the blood shall be mixed with an anticoagulant and a preservative (CCR Title 17, Sec.1219.1(c)(2)).  These are the main legal requirements of a valid DUI blood draw.  If the government can’t prove beyond a reasonable doubt that they complied with blood collection requirements, you can win because the forensic evidence is compromised.

Failure To Comply With California’s Title 17 Regulations

A failure to follow the regulations can result in inaccurate alcohol test results.  That is why in a California DUI case, if the evidence demonstrates that the person administering the tes,t or agency maintaining the testing device, failed to follow Title 17 regulations the jury is given an instruction that states “In evaluating any test results in this case, you may consider whether or not the person administering the test or the agency maintaining the testing device followed the regulations of the California Department of Public Health [Title 17].”   The most important sections relevant to DUI testing are as follows: 

California Code of Regulation 1215.1

(c) “Breath Alcohol Analysis” means analysis of a sample of a person’s expired breath, using a breath testing instrument designed for this purpose, in order to determine the concentration of ethyl alcohol in the person’s blood.

(d) “Concentration” means the weight amount of alcohol contained in a unit volume of liquid or a unit volume of gas under specified conditions of temperature and pressure; in the case of a solid tissue specimen, “concentration” means the weight amount of alcohol contained in a unit weight of specimen.

1219.1. Blood Collection and Retention.

(a) Blood samples shall be collected by venipuncture from living individuals as soon as feasible after an alleged offense and only by persons authorized by Section 13354 of the Vehicle Code.

(b) Sufficient blood shall be collected to permit duplicate determinations.

(c) Alcohol or other volatile organic disinfectant shall not be used to clean the skin where a specimen is to be collected. Aqueous benzalkonium chloride (zephiran), aqueous merthiolate or other suitable aqueous disinfectant shall be used.

(d) Blood samples shall be collected using sterile, dry hypodermic needles and syringes, or using clean, dry vacuum type containers with sterile needles. Reusable equipment, if used, shall not be cleaned or kept in alcohol or other volatile organic solvent.

(e) The blood sample shall be deposited into a clean, dry container which is closed with an inert

stopper.

(1) Alcohol or other volatile organic solvent shall not be used to clean the container.

(2) The blood shall be mixed with an anticoagulant and a preservative.

(g) In order to allow for analysis by the defendant, the remaining portion of the sample shall be retained for one year after the date of collection.

(2) Whenever a sample is requested by the defendant for analysis and a sufficient sample remains, the forensic alcohol laboratory or law enforcement agency in possession of the original sample shall continue such possession, but shall provide the defendant with a portion of the remaining sample in a clean container together with a copy

1219.3. Breath Collection.

A breath sample shall be expired breath which is essentially alveolar in composition. The quantity of the breath sample shall be established by direct volumetric measurement. The breath sample shall be collected only after the subject has been under continuous observation for at least fifteen minutes prior to collection of the breath sample, during which time the subject must not have ingested alcoholic beverages or other fluids, regurgitated, vomited, eaten, or smoked.

1221.4. Standards of Procedure.

(a) Procedures for breath alcohol analysis shall meet the following standards:

(1) For each person tested, breath alcohol analysis shall include analysis of 2 separate breath samples which result in determinations of blood alcohol concentrations which do not differ from each other by more than 0.02 grams per 100 milliliters.

(2) The accuracy of instruments shall be determined.

(A) Such determination of accuracy shall consist, at a minimum, of periodic analysis of a reference sample of known alcohol concentration within accuracy and precision limits of plus or minus 0.01 grams % of the true value; these limits shall be applied to alcohol concentrations from 0.10 to 0.30 grams %. The reference sample shall be provided by a forensic alcohol laboratory.

1. Such analysis shall be performed by an operator as defined in Section 1221.4 (a)(5), and the results shall be used by a forensic alcohol laboratory to determine if the instrument continues to meet the accuracy set forth in Section 1221.4 (a)(2)(A).

(B) For the purposes of such determinations of accuracy, “periodic” means either a period of time not exceeding 10 days or following the testing of every 150 subjects, whichever comes sooner.

(3) Breath alcohol analysis shall be performed only with instruments for which the operators have received training, such training to include at minimum the following schedule of subjects:

(A) Theory of operation;

(B) Detailed procedure of operation;

(C) Practical experience;

(D) Precautionary checklist;

(E) Written and/or practical examination.