Lecture on Analytical Chemistry in BAC testing Part 13

The above is Part Thirteen 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:

In the interest of time… I am dedicated to getting this done under time. Hemeoconcentration is outlined in here.  You can read it on your own.

Immediate inversion. How to stop Candida Albican and blood clotting from happening is through immediate inversion. That means, as soon as it comes out of the person’s arm you have to invert the tube. You will never be able to crush a phlebotomist in court.  The only thing you are going to be able to do is look like you are a meanie to them. I always ask them in an open question,

“What did you do with the blood after you got it out?”

“I put it in the tray”

“Are you sure?”


“Are you double sure?”


“That’s the way you always do it?”


Get them committed to that.  There is no inversion there.  Leave it alone.

Or number two:

“I took it and inverted the tube.”

And they will show you shaking it up and down. That can cause hemolysis but more important, it is the wrong way of doing it.

This is the way it is supposed to be done as opposed to what they actually do. They take it out of the arm, take the needle out and either do nothing or shake it up and down. That is not the right way to do it. That is not mixing it. That is not the proper way of mixing it. Instead what they should do after they take it out of the arm, remove the needle, gently invert it. I want you to watch this and see how long it takes to do this because it takes a long time to do this properly. You are trying to get those salts at the bottom to evenly distribute throughout the blood. That is only done by doing it slowly so that the bubble that is there transverses the entire thing and evenly distributes it. It takes forever.

Do not be afraid of the phlebotomist and the open ended question because even if they know they are supposed to invert the tube, or the DA tells them to make sure they remember that that they inverted the tube, have them show it in front of the jury and they will likely only do it three times or less. Not the magic eight times. Eight times is the key, which is what the manufacturer says. It takes forever.  It is still going on right now. The reason why is because of clotting. If you don’t have the correct activation of the tubes, not only is Candida Albican a problem but so is clotting. You will get a state scientist or a supposed scientist who will come in and say, “I can always spot clots.  No problem.  It is no issue.  I can always see it.”  Yes, you are right, you can, that is a clot right there. If it is inside the tube, you are not going to be able to spot it. It can cause great problems because it converts what is supposed to be a whole blood sample into a serum sample. Remember, a serum sample is over reported as we talk about earlier. You need to have inversion.

Short draw versus long draw has to do with salting out, which we will get to in a minute.

Once of the important things you have is that no phlebotomist is ever going to remember your guy or this tube as opposed to anything else. This lends itself to a great amount of cross examination which is, “You do not remember my guy.  You don’t know my guy.  And you don’t remember anything about this tube. The only thing you are going to tell me is that this is the way you always do it but you never make a mistake.” That is basically what they are going to try to sell to the jury.  Their habit.  Their custom, their perfection.

That is one way but another way to take a look at it is, in your closing look at it very closely. In criminal law there is not the presumption that the analyst did it right. There is not presumption that the tube was inverted. There is no presumption that there wasn’t Candida Albican. There is only one presumption in a criminal case and only one, the presumption of innocence. You cannot presume that the people in the lab did it right. You can believe they meant to do the right thing but you have to prove it.

Specimen collection.  We talked about some of those things.

The difference between a technologist, a machine operator, and an expert. Do not let a machine operator come in and try to tell you about salting out or any of these other things that we went through.

Pipetting, all these are dependent upon how much volume you get. It is like baking a cake.  If you don’t do it the right way, then you are going to get something wrong. Those are analytical things.

Hemolysis we touched on already. You can read about that.  Hematocrit you can also read about.

What I really want to do here is talk to you about my second to last concept.  The problem of salting out. If you remember in this particular slide how we arrived at getting a gas chromatography type of result and how it elutes out the chemicals and that is based on the head space, the partitioning that occurs. If the draw is too low, meaning that instead of 10 milliliters  you are getting 6, 5, 4 it lends itself to what is called salting out effect.

As we had talked about before, it is the heating, the incubation that has the analytes of interest that we are looking for going up into the gaseous phase, to the top phase. On the left hand side is what we would expect to see if everything was normal and right. In a short draw, the salt is in that same tight space, like a very enclosed closet.  There is too much ethanol pushed out of the liquid phase and it creates the salting out effect. The salting out effect means that it reports too much. It is not important for you to understand the process but important to understand that the low blood sample amount, instead of the 10 mL, if it is 6, 5 or 4 that is no good.

Chain of custody, I think most people know chain of custody and how important it is but one of the things that I think is very important is to take a look at the magic number and how we arrive at it and what that means. I was hoping to show you is this.

[TV Clip]

What they are doing is pulling a magic number out of the hat. You have to understand the process of how it goes and the uncertainty. The big thing to know is that at the end of the process, you cannot let them come into the court and say that it is a .162 without saying it is a plus or minus amount and that over a period of time there is enough variance there. Measurement is a single representation in time and has to do with accuracy and precision.

What we constantly deal with and what we constantly fight against is the conflict between the war on DUI and the war on truth and the dueling axes that go along with that. Sometimes you feel like you are the person in the middle.

The most important thing that I hope you take away from this lecture is that there is a whole world of analytical chemistry out there. Do not accept a number being reported as a .162 as an absolute any more than you would a police report that says your guy is guilty of DUI. You need more information. You need to peel back the onion. You need to take a look at it.

I would like to thank you for your time. My name is Justin McShane and I am so happy to be here with you.

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