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Could vials used by Fort Worth police alter blood alcohol results? Some experts say yes

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Video of a San Antonio, Texas, driver confronting a man for drunk driving after he crashed into concrete highway divider has gone viral on Twitter. Deandre Lewis filmed the man crash into a barrier on West Military Drive on Feb. 27. KSAT reported

Vials that have been used for years by Fort Worth police to collect blood from suspected drunken drivers may be affecting the reliability of blood alcohol test results, according to a defense attorney and experts interviewed by the Star-Telegram.

To save money, the department has been using the smaller vials and assembling its own kits to test blood samples for alcohol concentration rather than buying ones already made.

But some experts say those smaller tubes contain far less of the additive needed to help prevent fermentation. Fermentation, they say, could result in a higher blood alcohol concentration result.

“You’re talking about people’s freedom,” said Dr. Jimmie Valentine, a medical pharmacology and toxicology consultant based in Gulfport, Mississippi. “If you wrongly convict them, you’ve convicted somebody ... on bad science. That’s not acceptable.”

Defense attorney Frank Sellers said he noticed the smaller vials when he was defending a 33-year-old Lubbock man in a misdemeanor DWI trial last month.

“When they brought the vials out with the officer, I went up and I looked at it and I knew immediately it as the wrong vial and there was a problem,” Sellers said.

But the Tarrant County District Attorney’s office, Fort Worth police and its crime lab stand behind the use of the smaller vials.

“We agree with the judge in the trial that the Fort Worth Crime Lab is not and was not using the wrong tubes,” said Samantha Jordan, a spokeswoman with the District Attorney’s Office. “This was simply a defense ploy that the jury didn’t buy.”

Though the defendant was ultimately found guilty of driving while intoxicated, Sellers said jury members told the judge after the trial that they disregarded the blood test in reaching their verdict.

Criminal Court 4 Judge Deborah Nekhom, who presided over the case, did not return messages from the Star-Telegram seeking comment.

In the weeks since the trial, Sellers said he has not heard of any changes taking place, nor seen any Brady notices being issued by the District Attorney’s office in regards to the smaller vials. Under Brady disclosure, named for the U.S. Supreme Court ruling Brady v. Maryland, prosecutors must make available to the defense any exculpatory or impeaching information and evidence that is material to the guilt, innocence or punishment of a defendant.

“I’m not going to tell an elected official how to do their job but I think the appropriate legal move is to get to the bottom of how many cases have tubes that are inappropriate for forensic analysis and those blood tests just simply need to be thrown out,” Sellers said. “At the very least though, it’s Brady material that needs to be brought to the attention of the defense lawyers and the defendants who have affected cases.”

Blood collection standards

At issue is the recommended amount of sodium fluoride — a powder additive that helps prevent new alcohol from being formed in the sample through fermentation.

“That’s particularly important in a toxicology test because blood samples, in particular, are subject to what’s called in-vitro changes,” said Janine Arvizu, an Albuquerque-based chemist and auditor who testified on behalf of the defense in last month’s trial. “Those are actual chemistry changes that happen inside the tube after the blood is collected.”

Recognized consensus standards of the Clinical and Laboratory Standards Institute advise that blood specimens expected to be stored for more than 48 hours should be preserved with higher concentrations of sodium fluoride — 10 milligrams per milliliter.

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A 10-milliliter tube used by Arlington police to draw blood of suspected intoxicated drivers. Courtesy Arlington Police Department

The 10-milliliter vials typically used in the kits are made of glass and have a gray rubber stopper that creates a vacuum seal. They contain the recommended 100 milligrams of sodium fluoride and 20 milligram of potassium oxalate, an anticoagulant.

The smaller tubes used by Fort Worth police are made of plastic and also have a gray vacuum-seal lid. These tubes contain 12 milligrams of potassium oxalate and only 15 milligrams of sodium fluoride — a quarter of the recommended amount.

“The 6-milliliter tube that they’re using is designed to to be used clinically to do glucose analyses in a patient,” Valentine said. “It contains less sodium fluoride and less potassium oxalate than is deemed necessary to prevent the sample from fermenting.”

Arvizu agrees.

“Even if the lab does a perfect job and they analyze that blood in that tube just perfectly, the blood in the tube may not represent what was in the person, and that’s what matters for a forensic test,” she said.

If fermentation occurs, experts say, a higher blood alcohol level could result.

“You’d get a greater amount of alcohol forming in the tube so what was collected from the vein in the person is not the same as they analyzed in the lab,” Valentine said. “It’s created some alcohol in there and that could cause somebody to be falsely convicted on an alcohol test.”

Fort Worth police say they have used the smaller tubes for at least seven years and have no plans to stop.

“They are still using these same vials today,” Lt. Brandon O’Neil wrote in an email responding to several questions submitted by the Star-Telegram. He wrote that the Tarrant County District Attorney’s Office accepts the cases with these vials and has not identified any issues with them.

O’Neil said the DWI kits assembled by the department contain three vials, labels and mandatory forms that are sealed and placed in an envelope and delivered to the crime lab for processing. He said John Peter Smith Hospital, where certified nurses draw the blood, provides other materials like the syringes and wipes.

“Simply purchasing the vials in bulk is cheaper than purchasing a pre-made kit that may or may not need correct forms added,” O’Neil said.

He said the kits are carried by DWI officers, crime scene officers and are often available at JPS Hospital.

BD Diagnostics, which makes the tubes used by Fort Worth police, provides a “certificate of compliance” that states its 10-milliliter tube “is manufactured specifically for blood alcohol determination.”

“The chemicals added to this tube will not disturb the integrity of the blood sample relative to the alcohol content,” the certificate states.

For the 6-milliliter tubes, BD Diagnostics provides only a “certificate of conformance” that certifies the tube is sterile.

Mike Ward, forensic science division manager for the Fort Worth police crime lab, said the lab has been analyzing the smaller tubes for approximately 25 years, before 10-milliliter tubes had even been designated for blood alcohol analysis by any manufacturer.

Ward said only one manufacturer, BD Diagnostics, designates the 10-milliliter tubes for alcohol analysis. He said the designation “does not scientifically mean” that using other tubes would be incorrect or provide inaccurate data.

Ward said “based on scientific studies and our research,” the Fort Worth crime lab determined the smaller plastic tubes are sufficient.

He said the lab also stores the blood samples under refrigeration, which studies have shown “provides integrity to blood samples in the presence or absence of sodium fluoride.” It usually takes three to four days for blood to be tested after its drawn, he said.

Suzanne Perry, a Vancouver-based analytical chemist and scientific consultant, said she’s never seen a study showing 6-milliliter and 10-milliliter tubes “performing equally” in inhibiting fermentation.

“I don’t want drunk drivers on the road either, but they’ve got to do it right,” Perry said.

Dr. Peter Stout, president and CEO of the Houston Forensic Science Center, says in forensics, consensus standards are merely recommendations.

“You’d prefer to follow the recommendation but not having followed it doesn’t negate the value of the sample that is there,” Stout said.

Stout said there are multiple factors that go into maintaining the integrity of a blood sample.

“It’s not just simply preservatives that we’ve got to worry about. It’s preservatives, refrigeration, and that the draw is cleanly done and that the analytical process is appropriately done,” Stout said. “Simply how much preservative is there is not as big a deal as refrigeration.”

Stout said the presence or absence of a preservative is going to have less effect in refrigerated samples tested within three to four days. Any changes, he said, would more than likely decrease, rather than increase, the blood alcohol level.

Circumstances necessary for fermentation, which would cause the alcohol level to go up, are “highly unusual,” he said.

“It’s possible but the circumstances are pretty specific so it’s not real probable,” Stout said. “But the problem is I can’t tell you just how improbable.

“Certainly for the defense side, that’s always a concern. If there’s anything that’s going to make the alcohol go up, jeez, that’s a huge problem. Of course, if you’re the person who got run over and the alcohol could go down, that’s a problem, too.”

Science questioned on smaller tubes

Valentine, the toxicology consultant, said he never heard of an agency using plastic 6-milliliter tubes in blood collection for alcohol testing and applauded Sellers for going public about the practice.

“You just shouldn’t do it. It’s going against the mainstream of the science that we know about,” Valentine said.

“If Fort Worth police want to do extensive validation studies and publish it in the scientific literature showing these tubes gave the same result as the glass tubes, that’s fine,” Valentine said. “But we don’t have any of that kind of data right now and in science, we always say show me your data. I don’t have any data from them showing that is OK to do.”

Deandra Grant, a Richardson defense attorney who handles intoxication cases across the state, is a national speaker on DWI law and science, and is co-author of “The Texas DWI Manual.” Grant said she has never worked a case where 6-milliliter tubes were used to collect blood for a blood alcohol concentration test.

“I’d like to know their scientific basis for using that tube,” Grant said.

Though multiple Tarrant County law enforcement agencies contacted by the Star-Telegram say they use 10-milliliter tubes for blood draws, Tarrant County Medical Examiner Dr. Nizam Peerwani indicated some of the 33 agencies the department serves also use the smaller tubes.

“Size of the tube has no bearing on test results provided the blood specimen is appropriately collected,” Peerwani wrote in an email.

He did not respond to a question asking for the names of the law enforcement agencies using the smaller tubes.

In last month’s DWI hearing, Sellers said he purchased a ready-made blood kit to show jurors the correct vial that should have been used in drawing his client’s blood.

“We were able to show the jury here’s how it’s supposed to be done, not this DIY assembly line that they’ve created in the Fort Worth Police Department using the wrong materials,” Sellers said.

According to Ward, from the Fort Worth crime lab, the scientist who tested the blood has performed 180 blood alcohol tests during her employment and is one of seven scientists in the crime lab’s chemistry unit qualified to perform blood alcohol content analysis.

Over the past 25 years, the lab has analyzed 20,000 to 30,000 blood alcohol content samples. Most, Ward said, involved the 6-milliliter tubes, but the lab has also seen 4-milliliter and 10-milliliter tubes.

Sellers is troubled that the 10-milliliter tubes aren’t being used.

“Who knows how many of those were manslaughter cases, or serious cases where if you’re on the line between .07 and .08, it makes a big difference what kind of tube was used,” Sellers said.

BEHIND OUR REPORTING

How we did it

After receiving information that questions had been raised during a DWI trial last month regarding the vial used by Fort Worth police for blood alcohol testing, the Fort Worth Star-Telegram reached out to attorneys who specialize in DWI cases, several experts in the fields of toxicology and chemistry, and to the manufacturer of the vials used by Fort Worth police to determine if the vial used by Fort Worth police could affect blood alcohol concentration test results.

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