Impact of Substance Use Disorder on Tryptophan Metabolism Through the Kynurenine Pathway: A Narrative Review.

: Substance use disorder is a crisis impacting many people in the United States. This review aimed to identify the effect addictive substances have on the kynurenine pathway. Tryptophan is an essential amino acid metabolized by the serotonin and kynurenine pathways.

Despite the improved clinical sensitivity of the Roche benzodiazepines II assay it cannot replace mass spectrometry in all patient populations.

Introduction: Benzodiazepines are frequently prescribed and misused therefore urine drug screening (UDS) is performed in many patient populations. Most current benzodiazepine immunoassays have poor sensitivity, particularly for detecting the metabolites of newer benzodiazepines such as lorazepam in urine.

Objectives: We aimed to verify the clinical performance of the new qualitative Roche Benzodiazepines II (BNZ2) immunoassay, as well as compare its performance to the Roche Benzodiazepines Plus (BENZ) assay in two patient populations: UDS in the emergency department (ED) and compliance monitoring.

Immunoassay-Based Drug Tests Are Inadequately Sensitive for Medication Compliance Monitoring in Patients Treated for Chronic Pain.

Background: Enzyme immunoassays (EIA) have notable limitations for monitoring therapeutic compliance in pain management. Chromatography coupled with mass spectrometry provides definitive results and superior sensitivity and specificity over traditional EIA testing.

Objective: To analyze and compare the sensitivity of EIA results together with known prescriptions to liquid chromatography-tandem mass spectrometry (LC-MS/MS) for monitoring drug use (and abuse) in patients treated for chronic pain.

KIMS, CEDIA, and HS-CEDIA immunoassays are inadequately sensitive for detection of benzodiazepines in urine from patients treated for chronic pain.

Background: Patients treated for chronic pain may frequently undergo urine drug testing to monitor medication compliance and detect undisclosed prescribed or illicit drug use. Due to the increasing use and abuse of benzodiazepines, this class of medications is often included in drug screening panels. However, immunoassay-based methods lack the requisite sensitivity for detecting benzodiazepine use in this population primarily due to their poor cross-reactivity with several major urinary benzodiazepine metabolites.

Improved buprenorphine immunoassay performance after urine treatment with β-glucuronidase.

Buprenorphine (BUP), a semi-synthetic opioid analgesic, is increasingly prescribed for the treatment of chronic pain and opioid dependence. Urine immunoassay screening methods are available for monitoring BUP compliance and misuse; however, these screens may have poor sensitivity or specificity. We evaluated whether the pretreatment of urine with β-glucuronidase (BG) improves the sensitivity and overall accuracy of three BUP enzyme immunoassays when compared with liquid chromatography-tandem mass spectrometry (LC-MS-MS).

Significant cost savings achieved by in-sourcing urine drug testing for monitoring medication compliance in pain management.

Introduction: Reference laboratory testing can represent a significant component of the laboratory budget. Therefore, most laboratories continually reassess the feasibility of in-sourcing various tests. We describe the transfer of urine drug testing performed for monitoring medication compliance in pain management from a reference laboratory into an academic clinical laboratory.

Development of a fast and simple liquid chromatography-tandem mass spectrometry method for the quantitation of argatroban in patient plasma samples.

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the direct measurement of argatroban in human plasma was developed and compared with the activity-based Hemoclot Thrombin Inhibitors assay. UPLC-MS/MS was performed using diclofenac as an internal standard. In summary, argatroban and diclofenac were extracted from 100 μL of plasma using a methanol precipitation protocol, and chromatographic separation was performed on an ACQUITY TQD mass spectrometer using a UPLC C18 BEH 1.

A new highly specific buprenorphine immunoassay for monitoring buprenorphine compliance and abuse.

Urine buprenorphine screening is utilized to assess buprenorphine compliance and to detect illicit use. Robust screening assays should be specific for buprenorphine without cross-reactivity with other opioids, which are frequently present in patients treated for opioid addiction and chronic pain. We evaluated the new Lin-Zhi urine buprenorphine enzyme immunoassay (EIA) as a potentially more specific alternative to the Microgenics cloned enzyme donor immunoassay (CEDIA) by using 149 urines originating from patients treated for chronic pain and opioid addiction.

A new automated urine fentanyl immunoassay: technical performance and clinical utility for monitoring fentanyl compliance.

Background: Opiate and other drugs of abuse screening assays have been available for many years, and successfully utilized for monitoring patient medication compliance and for detecting misuse. However, immunoassays designed to rapidly detect the highly potent synthetic opioid, fentanyl, have not been available.

Methods: We evaluated a new fentanyl homogeneous enzyme immunoassay (HEIA) (Immunalysis Corporation) for its ability to accurately detect fentanyl in 307 urine samples from patients prescribed chronic opioid therapy.

Patient misidentifications caused by errors in standard bar code technology.

Background: Bar code technology has decreased transcription errors in many healthcare applications. However, we have found that linear bar code identification methods are not failsafe. In this study, we sought to identify the sources of bar code decoding errors that generated incorrect patient identifiers when bar codes were scanned for point-of-care glucose testing and to develop solutions to prevent their occurrence.

Quantification of busulfan in plasma using liquid chromatography electrospray tandem mass spectrometry (HPLC-ESI-MS/MS).

Busulfan is a chemotherapy drug widely used as part of conditioning regimens for patients undergoing bone marrow transplantation (BMT). Challenges of busulfan treatment include a narrow therapeutic window and wide inter- and intra-patient variability. Inappropriately low drug levels lead to relapse and even graft rejection, while higher doses frequently have toxic and sometimes fatal consequences.