In Georgia, as in many other jurisdictions, DUI blood samples are typically tested for alcohol content using published processes by the Georgia Bureau of investigation. The procedure generally involves several key steps:

1. Collection and Preservation of the Sample: The blood sample is not always collected in a controlled and sterile environment like a hospital and not always by a trained medical professional like a nurse. It’s important that the blood is drawn in a way that prevents contamination or fermentation. The sample is often preserved with anticoagulants and preservatives (Like Sodium Fluoride 15mg, Potassium Oxalate 12mg) to prevent the blood from clotting and to inhibit microbial growth, which can produce alcohol post-drawing.
2. Chain of Custody: Maintaining a strict chain of custody is crucial. This means that from the moment the blood is drawn until it’s analyzed, every transfer of the sample is documented and accounted for. This ensures the integrity of the sample and is crucial for legal purposes. This is often a source of potential error
3. Transport and Storage: The sample is securely transported to a testing facility. It must be stored at a proper temperature until analysis to prevent decomposition or other changes. The GBI sends blood samples through the regular mail, unfrigerated even in the oppressive heat of a Georgia summer.
4. Analysis: The most common method for analyzing blood alcohol content (BAC) is Gas Chromatography/Mass Sprectrometry (GC/MS). In this process:The blood sample is vaporized.
   • The vaporized sample is then passed through a column in the gas chromatograph.
   • Different substances in the sample, including alcohol, travel through the column at different speeds and are detected and quantified.
   • The amount of alcohol is then measured, and the BAC is calculated.
   • Mass spectrometry (MS) is a powerful analytical technique used to measure the masses within a sample and confirm the compound measured in the gas chromatography peak. It works by ionizing chemical compounds to generate charged molecules or molecule fragments and then measuring their mass-to-charge ratios and comparing them with known samples. There are several extensive mass spectral libraries and databases, such as the NIST/EPA/NIH Mass Spectral Library, the Human Metabolome Database (HMDB), and the MassBank database. These libraries contain reference spectra for thousands of different compounds and are widely used for compound identification. The GBI does not want to pay for NIST/EPA/NIH Mass Spectral Library so they have made their own MS sample library. The other two databases are free. Can you say GBI Homebrew?
5. Interpretation of Results: A toxicologist or a trained professional interprets the results. They write up an official report that is stripped of all data and just types in the result on official letterhead. To see the actual results, you must obtain the “lab pack,” “data pack” and “calibration pack.” The legal limit for blood alcohol content in Georgia, as in most U.S. states, is 0.08% for drivers aged 21 and over, and lower for commercial drivers (0.04 grams) and those under 21 (0.02 grams).
6. Reporting: The final step is the creation of a conclusory report with no underlying data that details the findings. There are actual two blood alcohol results generated which are averaged together and then rounded up. This report can be used as evidence in legal proceedings.

However, there are some general critical areas of error to be aware of when interpreting GC/MS data:

1. Misidentification of peaks: Attributing a peak to the wrong compound can lead to inaccurate conclusions about the sample composition. This can occur due to relying solely on retention times for identification, overlooking coelution (where two compounds elute or leave the column or tube at the same time), or misinterpreting mass spectral data.
2. Improper quantification: Quantifying the amount of a specific compound in the sample requires careful consideration of various factors, including calibration standards, response factors, and injection volume. Errors in these areas can lead to over- or underestimating the actual concentration.
3. Ignoring blank contamination: Background contamination from the instrument or analysis process can contribute to peaks in the chromatogram. Failing to account for this contamination can lead to misinterpreting the presence or amount of certain compounds in the sample.
4. Overlooking limitations of the technique: GC/MS, like any analytical technique, has limitations. Attorneys should be aware of these limitations and avoid drawing conclusions beyond the scope of the data. For example, GC/MS may not be able to detect certain types of compounds or may not be able to distinguish between structurally similar compounds.

It’s important to remember that interpreting GC/MS data is a complex task that requires a combination of knowledge, experience, and careful attention to detail. By being aware of these common errors, attorneys can help to ensure the accuracy and reliability of their results and make sure that their clients are not convicted using unreliable information or data.

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