Comments on: Blood Alcohol Tests: The Hematocrit Conundrum http://gaduiblog.com/2009/10/08/blood-alcohol-tests-the-hematocrit-conundrum/ A Guide for Everything Related to DUI in Georgia Fri, 18 May 2012 05:18:22 +0000 http://wordpress.org/?v=2.2.1 By: justin@themcshanefirm.com http://gaduiblog.com/2009/10/08/blood-alcohol-tests-the-hematocrit-conundrum/#comment-52887 justin@themcshanefirm.com Thu, 22 Oct 2009 15:30:17 +0000 http://gaduiblog.com/2009/10/08/blood-alcohol-tests-the-hematocrit-conundrum/#comment-52887 Great post. I would like to take it one step further. These are, of course, things that you know as you and I have spoken about it many a time. But the other issue is the validation of the science and whether or not it meets a Frye/Daubert challenge. Hospital blood is, of course, a colormetic spectrophometric enzyme reagent reaction test (the hospital blood plasma or blood serum test). Preamble: As long as you see this following chart in the insert , then the argument infra is sound Ethyl Alcohol+ NAD+ ----> Acetaldehyde+NADH+H+ PART ONE: The answer is there is no answer… First, there is absolutely no consensus in the scientific community as to the proper conversion factor. There is no number. Therefore, as there is no scientific agreement, then no number should be used by the Courts. It is a basic Daubert/Frye matter. The government as the proponent of the evidence has the burden to prove it is reliable and based on sound science. The very fact that there are studies that go as low as 1.10 overstatement to as high was 1.59 make it so. That is a 69% swing. Come on. The conversion factor depends on hematocrit (packed cell volume) entirely (well almost entirely, but for the sake of brevity it is the most important part). Serum or plasma (almost-one article had a statistical artifact) always over estimates BAC. Plasma actually more so. If I am forced to use a conversion factor AND THAT IS A BIG IF. I go with Professor Rainey and 1.49 which is the highest peer reviewed article that I could find as the presumption of innocence demands that we give all benefit to the accused. Also Dr. Citron has published a peer reviewed article on it. PART TWO: The answer is the science, the defense is the truth. Here is my logic proof… 1. If you accept as true that these Hospitals perform tests on less than [whole] blood 2. If you accept that these hospitals perform tests on blood plasma Then, would not the following be true… 3. Plasma blood and serum blood are more or less the same (or best case scenario for the defense the conversion is 1:1.04 serum:plasma) according to: Distribution of ethanol and water between plasma and whole blood; inter- and intra- individual variations after administration of ethanol by intravenous infusion Jones, A.W., Hahn, R.G., Stalberg, H.P.(1990),Scandanavian Journal of Clinical and Laboratory Investigation, 50(7), Nov. 775-780. Comparison of plasma, serum, and whole blood ethanol concentrations Winek, C.L., Carfagna, M. (1987), Journal of Analytical Toxicology, 11(6), 267-8. 4. If you accept Rainey’s assertion in Relation between Serum and Whole-Blood Ethanol Concentrations; Petrie M. Rainey: Clinical Chemistry, Vol. 39, No. 11, 1993. (pg 2288-2292) In that study (peer reviewed, scientifically reliable), Rainey studies the relationship between hospital (serum) blood test results and contemporaneous whole blood results. He finds that the median ratio for adjusting serum to whole blood is 1.15. The high of the range was 1.59. 1.49 for the central 99% (or 2 standard deviations) and 1.40 for the central 95%. Therefore, I like to use 1.49. 6. The combination of 1:1.04 serum:plasma and then 1:1.49 whole blood:serum, then mathematically 1.5496 if you really want to stretch. That is EXCLUDING the machine’s in-built range of analytical error, control run specific drift errors, pippetting errors, etc. It also presumes no exogenous alcohol production and perfect collection, inversion, transportation, storage, preparation and analysis. You cannot presume all of those things. There is only one presumption and that is the presumption of innocence. Just a lazy thought on a Thursday mid-morning. Thanks for the post. This blog is a wonderful resource. Justin J. McShane, Esquire http://www.paduiblog.com Great post. I would like to take it one step further. These are, of course, things that you know as you and I have spoken about it many a time.

But the other issue is the validation of the science and whether or not it meets a Frye/Daubert challenge. Hospital blood is, of course, a colormetic spectrophometric enzyme reagent reaction test (the hospital blood plasma or blood serum test).

Preamble: As long as you see this following chart in the insert , then the argument infra is sound

Ethyl Alcohol+ NAD+ —-> Acetaldehyde+NADH+H+

PART ONE: The answer is there is no answer…

First, there is absolutely no consensus in the scientific community as to the proper conversion factor. There is no number. Therefore, as there is no scientific agreement, then no number should be used by the Courts. It is a basic Daubert/Frye matter. The government as the proponent of the evidence has the burden to prove it is reliable and based on sound science. The very fact that there are studies that go as low as 1.10 overstatement to as high was 1.59 make it so. That is a 69% swing. Come on.

The conversion factor depends on hematocrit (packed cell volume) entirely (well almost entirely, but for the sake of brevity it is the most important part). Serum or plasma (almost-one article had a statistical artifact) always over estimates BAC. Plasma actually more so. If I am forced to use a conversion factor AND THAT IS A BIG IF. I go with Professor Rainey and 1.49 which is the highest peer reviewed article that I could find as the presumption of innocence demands that we give all benefit to the accused. Also Dr. Citron has published a peer reviewed article on it.

PART TWO: The answer is the science, the defense is the truth.

Here is my logic proof…

1. If you accept as true that these Hospitals perform tests on less than [whole] blood
2. If you accept that these hospitals perform tests on blood plasma

Then, would not the following be true…

3. Plasma blood and serum blood are more or less the same (or best case scenario for the defense the conversion is 1:1.04 serum:plasma) according to:

Distribution of ethanol and water between plasma and whole blood; inter- and intra- individual variations after administration of ethanol by intravenous infusion
Jones, A.W., Hahn, R.G., Stalberg, H.P.(1990),Scandanavian Journal of Clinical and Laboratory Investigation, 50(7), Nov. 775-780.

Comparison of plasma, serum, and whole blood ethanol concentrations
Winek, C.L., Carfagna, M. (1987), Journal of Analytical Toxicology, 11(6), 267-8.

4. If you accept Rainey’s assertion in Relation between Serum and Whole-Blood Ethanol Concentrations; Petrie M. Rainey: Clinical Chemistry, Vol. 39, No. 11, 1993. (pg 2288-2292)

In that study (peer reviewed, scientifically reliable), Rainey studies the relationship between hospital (serum) blood test results and contemporaneous whole blood results. He finds that the median ratio for adjusting serum to whole blood is 1.15. The high of the range was 1.59. 1.49 for the central 99% (or 2 standard deviations) and 1.40 for the central 95%. Therefore, I like to use 1.49.
6. The combination of 1:1.04 serum:plasma and then 1:1.49 whole blood:serum, then mathematically 1.5496 if you really want to stretch.

That is EXCLUDING the machine’s in-built range of analytical error, control run specific drift errors, pippetting errors, etc. It also presumes no exogenous alcohol production and perfect collection, inversion, transportation, storage, preparation and analysis. You cannot presume all of those things. There is only one presumption and that is the presumption of innocence.

Just a lazy thought on a Thursday mid-morning. Thanks for the post. This blog is a wonderful resource.

Justin J. McShane, Esquire
http://www.paduiblog.com

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