Forensic Toxicology Online Symposium

RTI International is offering their 2nd Annual Online Symposium: Current Trends in Forensics & Forensic Toxicology program May 13-17, 2019. The program is free of charge.

The program will feature speakers on various topics of toxicology and seized drug analysis. The program is intended for laboratory scientists who work in these fields so that they can receive additional training without having to leave the lab, but is available to the forensic community as a whole.

If you are interested in learning more about the latest trends in these fields, visit the program site for more information and registration.

ANSI/ASB Best Practice Recommendation 037, Guidelines for Opinions and Testimony in Forensic Toxicology

The American Academy of Forensic Science Standards Board (ASB) has published ANSI/ASB Best Practice Recommendation 037, Guidelines for Opinions and Testimony in Forensic Toxicology, First Edition. This document delineates guidelines for best practices in forensic toxicology opinions and testimony, including human performance toxicology (e.g., driving under the influence of alcohol or drugs), postmortem forensic toxicology, court-ordered toxicology (e.g., probation and parole, drug courts, child services), and general forensic toxicology.

The American Academy of Forensic Sciences (AAFS) is working to develop best practice recommendations through a consensus process for each forensic discipline. Though the guidelines are non-binding, they do represent a deliberative process by which a group of forensic science practitioners, researchers, and court system stakeholders have developed recommendations on training standards, lab procedures, quality assurance, report writing, and testimony for each field.

The 2009 National Research Council Report, Strengthening Forensic Science: A Path Forward, emphasized the need for improving quality assurances, including continued standards-setting and enforcement. They wrote:

…Standards and best practices create a professional environment that allows organizations and professions to create quality systems, policies, and procedures and maintain autonomy from vested interest groups. Standards ensure desirable characteristics of services and techniques such as quality, reliability, efficiency, and consistency among practitioners. Typically standards are enforced through systems of accreditation and certification, wherein independent examiners and auditors test and audit the performance, policies, and procedures of both laboratories and service providers.

The Guidelines for Opinions and Testimony in Forensic Toxicology aim to “ensur[e] that proper toxicological testimony is allowed in legal matters by defining the general areas of forensic toxicology that are viewed as reliable by other experts in the field.”

The Guidelines specify that experts should provide both an analytical toxicology report and a separate report that conveys their opinions if they will offer an opinion on the interpretation of the toxicology findings (Section 4.1). In other words, under the Guidelines, an expert who will testify about the impairing effects of substances should provide that opinion in a written report, in addition to reporting the quantitative results that are typically provided in a Lab Report.

Additionally, the Guidelines specify that an opinion should clearly state any assumptions made; clearly state any known limitations of the opinion; cite references to support the opinion (and such references should be provided in the report or made available upon request); and be based on the totality of information available, including case history, observations, circumstances, and other relevant information, and not based solely on analytical results. (Section 4.3)

The Guidelines also define what are considered appropriate (Section 5.2) and inappropriate (Section 5.3) opinions and testimony by a toxicologist. These sections reiterate that opinions about impairment must be include consideration of the context of the case and not be based solely on a quantitative result. Also, words such as “scientific certainty” or “reasonable degree of scientific certainty” should not be used in testimony unless required by jurisdictional regulations.

All ASB publications can be downloaded for free from the Published Documents section of the ASB website.

 

OCME Toxicology Lab Procedures available

The IDS Forensic website has posted the toxicology lab procedures from the NC Office of the Chief Medical Examiner here. Attorneys who would like to learn more about the procedures that the OCME toxicology lab uses to test evidence can read through the procedures.

For casework, attorneys should obtain the lab procedures that were in effect at the time that the evidence in their case was worked. Those procedures can be requested through discovery. The information posted on the IDS Forensic website should be used for general information purposes only and to give attorneys an idea of what procedures are available.

Hemp or Marijuana?

Your client is charged with possession of marijuana. They tell you they possessed hemp – not marijuana. Industrial hemp is not visually distinguishable from illicit marijuana. Is that a defense? I would say yes, if your client is a licensed industrial hemp farmer growing industrial hemp in compliance with all regulations. But, if your client is not a licensed grower, the argument is less straightforward.

Cultivation of industrial hemp is now permitted as part of a pilot program in North Carolina. The program is permitted under federal law. The N.C. General Assembly enacted statutes governing industrial hemp and the N.C. Industrial Hemp Commission develops rules for the industry.

Marijuana and industrial hemp are different varieties of the same plant species, Cannabis sativa L. The two species are identical in appearance, but industrial hemp is required to have less than 0.3 percent THC. See Industrial Hemp FAQs. 0.3 percent THC would not cause psychoactive effects if ingested. Marijuana typically contains 3-15% THC. See Industrial Hemp FAQs

The N.C. General Statutes define “marijuana” as all parts of the plant of the genus Cannabis. However, mature stalks and sterilized seeds and their oils are exempted from the statutory definition of “marijuana.” See N.C. Gen. Stat. § 90-87(16). Also, for licensed farmers, cannabis sativa can be possessed and cultivated, so long it contains a delta-9 tetrahydrocannabinol (THC) concentration of not more than three-tenths of one percent (0.3%) on a dry weight basis. N.C. Gen. Stat. § 106-568.51.

Industrial hemp farmers use the stalks and seeds to make a variety of products that are legal for consumers to possess. Statute defines hemp products as “[a]ll products made from industrial hemp, including, but not limited to, cloth, cordage, fiber, food, fuel, paint, paper, particleboard, plastics, seed, seed meal and seed oil for consumption, and certified seed for cultivation if the seeds originate from industrial hemp varieties.” N.C. Gen. Stat. § 106-568.51. Presumably, under state law, it is lawful for consumers to possess these products because they are made from the part of the plant that is exempted from the statutory definition of marijuana; and, therefore both growers and consumers can possess them.

The amount of THC contained in these products is very low and these products are difficult to ingest in large amounts. For example, it would be impossible to ingest enough hemp rope to experience psychoactive effects.

Cannabis sativa leaves with low amounts of THC are a by-product of industrial hemp production. It’s not clear to me whether they have any industrial use in NC, though they can be used to produce cannabidiol (CBD) oil, which is a form of hemp extract which has no psychoactive effects and is used as a treatment for intractable epilepsy. Like the stalks and seeds, the leaves contain very low amounts of THC; and, like the stalks and seeds, it would not be possible to get high from ingesting the leaves.

Though the leaves of low-THC industrial hemp does not cause any psychoactive effect, they are not exempted from the statutory definition of marijuana and cannot be legally possessed by anyone other than a licensed hemp grower. See N.C. Gen. Stat. § 90-87(16). The only other exemption for a hemp product in the General Statues is an exemption for use or possession of hemp extract for certain medical purposes. See N.C. Gen. Stat. § 90-94.1.

So, if the leaves do not pose a public health threat, why is it illegal to possess them? One could argue that leaves that are visually identical to marijuana could be sold as a counterfeit controlled substance, so there is a public policy interest in their possession remaining illegal. However, given that these leaves are incapable of causing any psychoactive effects when ingested or consumed, from a public health perspective, it seems that possessing the leaves is as innocuous as possessing hemp rope. Given that low-THC Cannabis sativa leaves are not impairing or psychoactive, one could argue that a possession charge should be dismissed in the interest of justice. If the person is charged with the Class I felony for possession of marijuana, counsel could argue that the defendant should be allowed to plead to the Class 1 misdemeanor of tampering with an industrial hemp crop established by N.C. Gen. Stat. § 106-568.57 rather than the felony.

I’m interested to hear from readers about how courts have handled cases involving possession of hemp leaves as this is a new topic for me given the recent introduction of industrial hemp in North Carolina.

Houston in the Blind

Blind studies and procedures are the gold standard of evaluating the quality and reliability of scientific results. Unfortunately, this has long been lacking in forensic science. Fortunately, strides are being made to introduce blind testing to forensics, most notably in the Houston Forensic Science Center (HFSC).

Currently, forensic scientists are tested periodically on their knowledge and ability through proficiency tests. However, scientists typically are aware they are completing a proficiency test and not case work. This allows for the Hawthorne effect to play a role in the testing, or the phenomena of a person behaving differently when they know they are being observed. Blind testing in forensic science will allow for blind samples to be included with case work in a manner that scientists cannot distinguish between a blind and a real case. This will help distinguish whether or not a laboratory adheres to guidelines and whether best practices are used in a day-to-day setting, as opposed to simply during an anticipated exam.

This article describes the efforts of Dr. Peter Stout, the HFSC’s chief executive officer (and former member of the NC Forensic Science Advisory Board), to implement a “blinds program.” So far, 329 blind samples have been integrated into normal casework in the firearms, toxicology, DNA, fingerprint, and digital forensic sections of the lab. In 2018, the lab plans to grow the program to 800 blind tests per year, or 5 percent of the lab’s workload.

Disguising a blind as a case sample is not a simple task, as the Forensic Magazine article describes. In addition to the challenge of creating a case submission that appears authentic, another particularly challenging aspect has been determining whether the blind samples could be searched in databases like AFIS, NIBIN, and CODIS.

At the HFSC, no errors have yet been reported in the testing of a blind. Use of blind tests will allow the lab to begin reporting error rates and confidence intervals, which will strengthen the testimony of analysts and allow them to answer questions about reliability of their work.

If you’ve made it this far in the post and are still wondering about the title, “Houston, in the blind” refers to a phrase used by astronauts when they aren’t receiving any response from ground control. The phrase indicates that they will continue to communicate, not knowing if ground control is receiving their message. My hope for forensic science is that communications about blind testing will not be “in the blind.”

 

 

Lab Tour on April 27

Would you like to learn more about how forensic toxicology testing is performed? Would you like to have a better understanding of how blood is tested for drugs or alcohol? Toxicologists Dr. Jay Gehlhausen and Dr. David Burrows will lead attorneys and investigators on a lab tour on April 27, 2018 in Wake Forest, NC at 10 am.

They will explain how blood and urine are tested for various substances, including through urine dip tests, immunoassay screening tests, and LC/MS-MS. Participants will be able to view the instruments and data and ask questions about the techniques used.

Attending a lab tour is a great way to improve your understanding of scientific evidence and its limitations. The tour and discussion will last about two hours. If you would like to attend, email Sarah.R.Olson@nccourts.org to sign up.

Mass. Supreme Court Considers Relevance of FSTs for Marijuana Impairment

Any practitioner that handles driving while impaired charges knows the significance of field-sobriety tests (“FSTs”) to the investigation and prosecution of drunk driving. Scientific research supports the basic idea behind the tests — that test performance on FSTs is an indicator of alcohol impairment. What about when the impairing substance isn’t alcohol at all? Do FSTs remain relevant for marijuana impairment? That was the question before the Massachusetts Supreme Court in Commonwealth v. Gerhardt, 81 N.E.3d 751, 2017 (September 19, 2017).

Background

Marijuana is legal for all purposes in the Massachusetts for adults 21 and older, but driving while impaired on the substance of course remains a crime. Some states where marijuana is legal have enacted drug limits for purposes of establishing impaired driving. Washington, for instance, has settled on a per se limit of 5 nanograms of THC (the primary active ingredient in marijuana) per milliliter of whole blood for drugged driving cases, similar to the .08 blood alcohol content limit for alcohol. In Colorado, that same amount of THC in the blood creates a permissive inference of impairment. The District of Columbia, by contrast, has a zero tolerance policy: any amount of the substance in the body is sufficient to be charged with drugged driving. Massachusetts, like North Carolina, has no per se limit for drugged driving when it comes to marijuana; the government has to prove impairment. A chemical analysis, by itself, will generally not suffice to prove impairment without a per se statutory limit. In cases where there is no statutory limit for the permissible amount of the impairing substance in the blood (or where there is no chemical analysis at all), officers often use FSTs to try to prove impairment, as they would in alcohol impairment cases. FSTs are therefore frequently substantial evidence in many (if not most) impaired driving prosecutions, regardless of the type of impairing substance. Gerhardt is one of the first cases to take a hard look at the use of FSTs in the context of a marijuana-only impaired driving prosecution.

Facts

Gerhardt was charged with Operating Under the Influence (the equivalent of NC’s DWI offense) after being stopped for failure to burn rear headlights. The officer reported smelling recently burned marijuana, and Gerhardt admitted he had smoked around three hours earlier. Gerhardt performed the HGN test, the Walk and Turn test, and the One-Leg Stand test, and other non-standard tests. He had no cues of impairment during the HGN test or the non-standard FSTs, but the officer detected several cues on the Walk and Turn and One-Leg Stand. Marijuana and paraphernalia were found in the vehicle as well. The Commonwealth sought to introduce evidence of Gerhardt’s performance on the FSTs and the officer’s interpretation of them. Gerhardt challenged the admissibility of that evidence under the Daubert expert-testimony standards.

Court’s Opinion

The court began by observing that standard FSTs were “designed to detect alcohol impairment” and that they do so by “assess[ing] an individual’s balance, coordination, dexterity, ability to follow directions, and ability to focus on multiple subjects at the same time.” Id. at 756. The court noted that established scientific research supports the reliability of the tests in the context of alcohol impairment, but that the same was not true for marijuana: “A significant amount of research has shown that consumption of marijuana can impair the ability to drive. There is ongoing disagreement among scientists, however, as to whether the FSTs are indicative of marijuana impairment.” Id. at 757. The court cites several studies that demonstrate the conflicting research—some studies have found substantial correlation between FSTs and marijuana impairment; some have found no such correlation; yet others find correlation between certain FSTs and marijuana impairment, but not others.

That said, the court wasn’t inclined to rule the tests completely irrelevant. Noting that the bar for relevance is low: “To the extent they are relevant to establish a driver’s balance, coordination, mental acuity, and other skills required to safely operate a motor vehicle, FSTs are admissible at trial as observations of the police officer . . .” Id. at 751. Just like the officer can attest to observations of driving, the odors of the vehicle or driver, and the appearance and behavior of the driver, the officer can testify to what he observed during the FSTs as a lay witness. “That marijuana can cause impairment of skills necessary to driving . . . is within the common experience and knowledge of jurors.” Id. at 759.

However, the court placed considerable limits on the use of such testimony, given the status of the science surrounding the use of FSTs in this context. The officer may not testify to whether the test was passed or failed and cannot testify that the results of the FSTs show marijuana impairment. Such testimony “improperly implies that the FST is a definitive test of marijuana use or impairment.” Id. at 759-760. Further, the officer should not call FSTs in a marijuana impairment case “tests”, as that signifies to the fact-finder that the FST is scientifically valid for the purpose of detecting marijuana impairment. The FSTs in this context should be referred to only as “roadside assessments.” Id. at 760. Perhaps most importantly, the lack of a scientific correlation between marijuana impairment and a defendant’s performance on FSTs means that the FST results, standing alone, are insufficient evidence to sustain a conviction. “The fact that FSTs cannot be treated as scientific ‘tests’ of impairment means that evidence of performance on FSTs, alone, is not sufficient to support a finding that a defendant’s ability to drive was impaired due to the consumption of marijuana, and the jury must be so instructed.” Id. (emphasis added). The court attached to its opinion a proposed jury instruction tracking that mandate. Finally, the officer also cannot offer a lay opinion that the driver was “high” on marijuana (although an expert opinion would be admissible). Because the effects of marijuana on individuals vary significantly, and because there is a lack of scientific evidence demonstrating common signs of marijuana impairment, a lay opinion that a defendant was intoxicated due to marijuana consumption is improper.

Impact in NC

So what’s the takeaway for practitioners? The case notes several studies on the connection between FSTs and marijuana impairment, which may be useful in a challenge to the use of FSTs in marijuana impairment cases. Because the studies are inconsistent, reference to them may support a finding that FSTs simply are not reliable in the context of marijuana impairment cases. Defense attorneys may point to Gerhardt as persuasive authority and argue for evidentiary limits on FST testimony in a marijuana impairment case similar to those imposed by the Gerhardt court, as well as for a similar jury instruction. Having the jury instructed on the fact that FSTs are not scientific evidence of impairment in this context would presumably be a powerful instruction. Likewise, preventing the officer from testifying that the defendant was impaired as a result of FST performance, that the defendant passed or failed the FSTs, that the officer’s lay opinion was that the person was impaired on marijuana, or from referencing the FSTs as “tests” at all, would be significant rulings in a DWI case with the potential to dramatically impact how the evidence of the case is presented to the finder of fact.  When confronted with a marijuana-only impaired driving case, defense counsel is encouraged to consider filing a pretrial motion in limine addressing the expert testimony and relevance concerns of this evidence in the context of the case. The logic of Gerhardt may also support extending the same limitations to other impairing substances—where the scientific research does not conclusively link the defendant’s performance on FSTs to impairment on the substance at issue, there is a strong argument to be had that the testimony should be similarly limited.

Despite the ubiquitous nature of FSTs in impaired driving cases, their use in a non-alcohol impaired driving prosecution should not be accepted by the defense without a challenge seeking to properly contextualize their efficacy in this area. Further, even where the trial court allows the evidence over defense objection, many of the points that an attorney would raise in a voir dire hearing on the admissibility of FSTs would also go to the weight of that evidence before the jury. One can imagine a fruitful cross of the officer on many of the points raised in the opinion. We’ll have to wait and see how NC courts address these concerns. In the meantime, Gerhardt is an indication that FSTs are properly treated as having less probative value in a marijuana case than in the more-routine alcohol case, and that the defendant is entitled to certain protections limiting the way that evidence is presented, at least as long as the science remains uncertain.

Language Matters: USDOJ’s Reporting Language and Testimony Guidelines

Forensic scientists are tasked with the job of explaining often complex scientific data to judges, jurors, and attorneys who may have little understanding of the science underlying the forensic analysis in a case.

Revelations in recent years that hair analysts provided testimony that had no scientific validity has highlighted the importance of using correct language to convey information about forensic analysis and its limitations. Several wrongful convictions have been overturned based on faulty testimony about hair evidence and a massive review of hair cases is ongoing.

In an effort to improve expert testimony, the U.S. Department of Justice has released proposed guidelines called the Uniform Language for Testimony and Reports. These guidelines, once finalized, will apply to all USDOJ personnel who issue reports or provide expert forensic testimony, and they will probably be viewed as best practices for the entire forensic community. The guidelines are currently accessible at https://justice.gov/dag/forensic-science, with the public comment section running through July 8, 2016.

Attorneys should be aware of these guidelines and be prepared to object to any lab report language or testimony that does not comply. For example, the Uniform Language for Testimony and Reports for the Forensic Latent Print Discipline provides the following guidance on what experts cannot say about their evidence: (1) they cannot state that two prints originate from the same source to the absolute exclusion of all other sources; (2) they cannot state that there is any statistical level of certainty attributed to their determination; (3) they cannot testify that their science is infallible. Similarly, for the testing of bodily fluids, analysts may not state or imply that a level of numerical certainty is calculated to support the identification of blood or semen (i.e., they cannot say they are 95 per cent confident that the stain contained blood or there is a one in a hundred chance that the stain was something other than semen) and may not state or imply that the methods used in performing serological examinations have error rates of zero or that they are infallible. For drug analysis, the guidelines specify that when no sampling plan was used and no reasonable assumption of homogeneity of an item was determined, the examiner may not report or state an opinion that the conclusions apply to the entirety of an item (or a percentage of the item). This limitation is important in pill cases where only one pill is tested.

So, if you have any suggestions about appropriate limitations for expert testimony, or the language they should use in reports, please take the time to provide feedback on these documents.

Reliability Concerns Regarding Probation Drug Screens

The NC Department of Public Safety (DPS) has begun relying on less accurate presumptive testing for urine screens for drugs for probation, prison, and DSS cases. The focus of this post will be probation cases, though the testing is the same for prison and DSS cases.

Testing Prior to 2014

Until February 2014, the Department of Public Safety maintained two laboratories with trained staff and EMIT analyzers (an immunoassay test) to run either initial testing or additional testing on urine that gave a positive result on an screening test. These labs tested approximately 125,000 samples per year. The North Carolina State Crime Lab uses similar equipment to the former DPS labs for presumptive toxicology testing.

Current Drug Testing Procedures

The DPS labs were closed in early 2014. On-site urine drug screening is now performed by probation officers using a presumptive test kit similar to the type of urine dip test that can be purchased over the counter at many stores. Currently, additional testing is completed by Norchem, a private lab in Arizona, only when the test subject immediately denies use of a controlled substance. If the test subject admits use, the urine specimen is discarded and a positive result is reported (See NC DPS Division of Adult Correction and Juvenile Justice – Community Corrections – Policy & Procedures – Chapter H – Section .0400 Substance Abuse Screening Program, available at https://www.ncdps.gov/div/CC/Publications/Policy.pdf, p. 367, subsection (i)). Because the urine sample is discarded, if the test subject later denies use, the sample cannot be re-tested using more reliable methods.

Reditest and the Need for Confirmatory Testing

The Reditest Panel Dip Test (“Reditest”) is the on-site screening test currently used by probation officers. The Reditest is one of many presumptive test kits which are intended to screen for drugs in urine. The Reditest package insert which describes how to use the product states in its “Limitations” section that the test “provides only a preliminary analytical test result. A secondary analytical method must be used to obtain a confirmed result.” The instruction card for a similar product can be found here. The instructions note that gas chromatography/mass spectrometry (GC/MS) is the “preferred confirmatory method.”

Reditest and Lack of Validation and On-Site Quality Assurance and Quality Control

Reditest recommends but does not provide “positive and negative controls to be tested as good laboratory practice to confirm the test procedure and to verify proper test performance.” Reditest kits are not being validated by the end user in North Carolina. If batches of test kits are not validated, there is no check on the accuracy of kits being used in the state. Immunoassay testing performed by the DPS labs prior to 2014 revealed that on several occasions the on-site test kits shipped to probation and other offices did not work as expected and yielded either inaccurate or uninterpretable results.

To administer the Reditest, a provider dips a portion of the card in a urine sample for 15 seconds. Five minutes later the results can be obtained. The card should have a control line appear in each testing area. If any line appears in the testing section (no matter how faint), the results are negative for that screen. If a line does not appear in the testing section, the manufacturer’s website explains how to send the sample to a laboratory for confirmatory testing. Administration of these presumptive tests by probation officers instead of individuals with scientific training further complicates the potential for incorrect results.

False Positives with Reditest

Included on the package insert are a subset of clinical studies which demonstrate the preliminary nature of the test. Agreement with GCMS, a more accurate confirmatory test, ranged from 89%-99%. The numbers demonstrate the possibility for false positives. In tests such as these, a false positive is typically caused by a legal substance which the kit confuses with an illicit drug. Most commonly this involves over-the-counter medications. For example, some kits will register pseudoephedrine as methamphetamine. The FDA also notes that results from these types of tests can be affected by how the test was performed, how the urine was stored, what the person ate or drank before taking the test, and any other medications the person may have taken.

Admissibility of Screening Test Results

In State v. Carter, 765 S.E.2d 56 (N.C. App. 2014), the N.C. Court of Appeals held that field drug test kits, which are presumptive tests, are inadmissible due to their lack of reliability. The Court noted that for testing of controlled substances to be admissible, it “must be based on a scientifically valid chemical analysis[.]” To establish that a test is admissible, the party must present evidence that the test methods are sufficiently reliable. Results of these initial tests without confirmatory testing should not be admissible and should not be sufficient for the basis of revocation of probation.

Screening Tests and Workplace Testing

Use of the Reditest would not meet federal guidelines for workplace testing. The U.S. Department of Health and Human Services (HHS) 2015 Mandatory Guidelines for Federal Workplace Drug Testing requires that an initial drug test be an immunoassay or alternate technology, such as spectrometry or spectroscopy. (Section 11.9, Available at https://www.federalregister.gov/articles/2015/05/15/2015-11523/mandatory-guidelines-for-federal-workplace-drug-testing-programs#p-426) An HHS-certified laboratory must validate an initial drug test before testing specimens. (Section 11.9) Initial test results must be confirmed by an analytical method that uses mass spectrometric identification. Such methods include gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), GC/MS/MS, LC/MS/MS] or equivalent. (Section 11.12) Only specimens that yield a positive result on initial and confirmatory tests are reported as positive results. (Section 11.17)

In North Carolina, the testing used to allege a probation violation, revoke probation or remove a child from a parent’s custody would not qualify as even an initial test in the federal employment context.

False Positives in Drug Field Testing Kits

The director of a lab recognized by the International Association of Chiefs of Police for forensic science excellence has called field drug testing kits “totally useless” due to the possibility of false positives. In laboratory experiments, at least two brands of field testing kits have been shown to produce false positives in tests of Mucinex, chocolate, aspirin, chocolate, and oregano. However, law enforcement agencies continue to employ these kits.

Fox 13 Tampa investigated the validity of drug field testing kits in the wake of arrests of three people based on false positives from field tests. Eventually all three were cleared and all charges were dropped. However, for the months between arrest and confirmatory testing by the state crime lab, the individuals felt that they were “guilty until proven innocent.”

Dr. Omar Bagasra, a research scientist at Claflin University, has been looking into the validity of field drug testing kits. In controlled tests in his laboratory, Dr. Bagasra, Dr. Cherilyn Haggen-Paey, and forensic scientist Chris Addanki, have demonstrated that the chemicals used in the kits are prone to give false positives even with common household materials. According to their tests, Mucinex can produce false positives for heroin and morphine; chocolate can be interpreted as marijuana; and soap can test positive as GHB. Even exposure to air caused false positives in some kits, according to their tests. The scientists noted that they had trouble interpreting results in a laboratory environment and “you can imagine in the field it’s even more difficult.” However, the experts say the problems are not linked to just the individual kits tested or a specific manufacturer, as many the field test kits tend to contain the same chemicals.

Field drug testing kits were created to screen for illicit substances in the field followed by more complete testing in a laboratory setting. However, the tests stand in for more scientifically valid testing until analysis at state crime labs occurs. Drug testing at state crime labs is typically performed just prior to trial due to the high rate of plea bargaining in drug cases, and therefore false positives are often not discovered unless contested at trial. During this time, the false positives from field tests can cause innocent citizens to be detained in jail for weeks or even months.

“False Positive Equal False Justice,” a 2008 report created for the California Attorneys for Criminal Justice, noted that false positives resulting in criminal charges has been an ongoing problem. In 2003, a Pennsylvania college student was held for three weeks when flour was mistaken for cocaine. In 2007, musician Don Bolles was arrested for possession of GHB which was actually soap. Additionally the report lists approximately forty extracts—such as vanilla, peppermint, or ginkgo—which can test as false positives for marijuana.

Dr. Frederic Whitehurst, a Ph.D. chemist and former FBI lab supervisor, has expressed concern with the use of field drug testing kits. He stated that he has “no confidence at all in those test kits.” Due to the high chance of false positives, both Dr. Whitehurst and Dr. Bagasra have recommended that drug field testing kits not be used. They say law enforcement would receive more valid results by waiting for results from lab testing. The kits are single use and range from a $4 to $20 a use depending on what drug is being investigated.

For more general information on forensic drug analysis see http://www.ncids.com/forensic/drugs/drugs.shtml.

Click here to read an article about the 2011 arrest of a man in Buncombe County based on a false positive field test result of cheese and tortilla dough.