Lecture on Analytical Chemistry in BAC testing Part 5

The above is Part Five from a lecture given by Attorney Justin J. McShane before the North Carolina Advocates for Justice “Advanced DWI Seminar”. This seminar happened on February 26, 2010. It was organized and hosted by John K. Fanney, Esquire of Fanney & Jackson, P.C. The following is a transcript of this video:

So to really understand what we are talking about here, you have to understand a little bit of science. What I mean by that is the distinction that is up here between whole blood, plasma blood, and serum blood. It is visually different. Over here is whole blood.  That means basically what came out of your arm and what got into the tube. Two other types of blood are plasma blood and serum blood. This is what they are doing a testing of over in the lab for hospital blood testing. They are visually different. Serum blood testing has a clot that is right there with the separation on the top. You can read what the components are as far as the difference between plasma and serum. But the most important thing to recognize is, like Sesame Street: “One of things is not like the others, one of these things…” This is whole blood.  It is visually different from plasma, visually different from serum blood.

I’m going to tell you that when they make the conversion between plasma and serum blood back into whole blood, because whole blood is what statutes are based upon.  If you are .08 state, which all states are – my state has different tiers, .08, .10. .16 – that conversion back between plasma blood and serum blood, if you believe it’s possible to do, results somewhere in the magnitude of a 59% overstatement. That means what comes out of their machines at the end of their process is about 59 % too much. It is 59% overstated and I am going to show you why. That’s because you are not testing the whole blood.  You are removing things out of it. What is important is for you to know the process so you can recognize when it is not a whole blood test. Because whole blood is what a conviction is based upon.  Meaning grams percent inside as an expression of weight, of volumetric weight, of whole blood as opposed to serum or plasma. If you have a plasma result or you have a serum result, it shouldn’t be reported in court as a whole blood result, but they do it all the time and I will show you how they do that.

This is what happens with the lab scientists. The lab scientist gets a nice, pretty, gray tube top  This is a pipette.  This is a solution and the solution has an acronym that’s called TCA (trichloroacetic acid).  What that is designed to do, it’s called a deproteinizing agent. Inside of our blood we have proteins, and what needs to be removed in order for these types of machines to work are the proteins because it interferes with getting a result at the end of the day. What happens is they take the pipette.  They load it up with TCA and then they put it in a tube. That is the first step that’s there.  What they do after that, they take that, they bring it over to what’s called a vortexer. What a vortexer does is it mixes up the TCA that’s inside of there. That takes the TCA, just like oil and water, and mixes it up so that it is homogenous, meaning it’s all the same type of thing mixed in there. It forms a pellet at the bottom because you are removing the protein. The protein binds, because of TCA and goes to the bottom.  You can see a pellet.

Next they take it over to a device called a centrifuge. The important thing to know about the centrifuge is that once it goes in there they load up a bunch of samples all at the same time and they spin it at a 450 angle. Has anyone seen the movie Spies Like Us? Remember that scene when they go to the centrifuge and the guy’s face is all getting smushed back and everything like that? That is a centrifuge. It is the same thing that happens here. Through the force that goes on when it spins around, what ends up happening is the lighter stuff goes to the top and the heavier stuff goes to the bottom. It’s pretty simple. It creates a very visible, distinguishable separation that’s there. This is what it looks like when it spins in there. There are variables that go in there. If you don’t spin it the right way then it’s no good.

The whole point is that after it comes out of the centrifuge, you can see the separation that’s there between the yellow viscous material, the plasma at the top; and at the bottom you can see what’s out there. So again, it turns into that distinction between the red blood cells, the heavier stuff’s at the bottom, the lighter stuff’s at the top.

I bring this all to you so that you can understand this next, most fundamental step. This is the most important step and this is how you are going to get them, and you are going to show in this process that it is not a whole blood result. It is the single biggest way that I know how to win these types of cases. If all you have to do is show that it is not a whole blood result and they don’t have someone to come in and testify scientifically as to their conversion rate because it is not whole blood.

It comes down to this nice little dirty secret. It’s centrifuged.  It’s separated, and what they do is they take the pipette and draw up just…  And it is called aspirating the supernate. If you are reading through your SOP’s (Standard Operating Procedures) of the hospitals, if you see the word supernate, you won. You don’t have to know anything else – just look for that word “supernate”. You aspirate, which means you draw up the supernate, which is only this yellow component. You don’t care about the rest. Then what you do after that – it goes over there into your specimen jar, and  then you take the rest of it.  Because you’re only taking the yellow viscous material, not all of it, just a very small portion of it, about that much into there.  You take the rest of it and you throw it away. That’s what they do in these labs.

They take the rest of the stuff, meaning the red blood cells, meaning the fibrin, meaning the proteins and they throw it away.  It never makes it to the analyzer. Then in your pipette is only that yellow viscous material. They take it over to an analyzer.  This is a Dade Dimension RXL Max, a highly complicated machine, at least it looks that way.  But the most important thing to know is that it is only testing, through that reagent process which we’ll go over in a minute, the yellow viscous material that is contained inside. So what ends up happening is, and this is an important distinction right here, is that the only thing that makes it to the machine, out of all the blood, out of your entire blood, is that yellow part, the plasma part.  So it is not a test on whole blood. It is a test on the yellow part or the supernate. That is the most important thing to take away from here.

But as we will see, there is a big difference between what happens in the clinical world and the forensic world. This is an interface that’s called the Laboratory Information System. The Laboratory Information System is a computer. This machine prints out little tickets, kind of like a BAC DataMaster or an Intoxilyzer or something like that.  But the Laboratory Information System is an external thing that doesn’t integrate with it. Someone sits there and puts in the hand input. It’s not connected to the machine, and reports the particular results. That’s what ends up happening, is they only test the yellow part of it.  And it is most distinctly, as you can see, it’s not whole blood.   It’s not whole blood.

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