Monthly Archives: August 2015

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.

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