Athena K. Petrides

HIGH-DOSE BIOTIN TREATMENT FOR SECONDARY PROGRESSIVE MULTIPLE SCLEROSIS MAY INTERFERE WITH THYROID ASSAYS.

OBJECTIVE To review cases and increase awareness in clinicians treating patients who may be taking biotin. METHODS We describe the presentation and workup of a woman with secondary progressive multiple sclerosis on high dose biotin with laboratory studies suggestive of thyrotoxicosis. RESULTS Plasma samples showed laboratory evidence of elevated thyroid hormone levels with elevated free thyroxine >7.8 ng/dl (reference interval (RI) 0.9-1.7 ng/dl) and decreased thyroid stimulating hormone <0.02 uIU/ml (RI 0.50-5.70 uIU/ml). Laboratory values normalized when biotin was withheld prior to repeat testing. CONCLUSIONS Our case report demonstrates that ingestion of high dose biotin in multiple sclerosis patients can cause interference with laboratory assessment of thyroid function. This interference causes laboratory values suggestive of thyrotoxicosis and can lead to unnecessary evaluation. Clinicians should be aware of the risk of laboratory interference in this patient demographic.

Decreased Escitalopram Concentrations Post-Roux-en-Y Gastric Bypass Surgery.

Background: There is a high coincidence between obesity and psychiatric disorders including depression. Depressive disorders are commonly treated with antidepressants, including the selective serotonin reuptake inhibitor Lexapro (escitalopram). Although candidates for elective Roux-en-Y gastric bypass (RYGB) surgery may be treated with escitalopram, drug dosing strategies are typically not adjusted postoperatively. Therefore, studies are needed to better characterize escitalopram drug concentrations in a postsurgical setting. Methods: Turbulent flow–liquid chromatographic–tandem mass spectrometric methods were used to quantify escitalopram concentrations in serum in study participants approved for RYGB. Blood was collected from study subjects 2 weeks before surgery, and 2 and 6 weeks postoperatively, to assess the impact of RYGB on systemic drug concentrations. Results: Twelve samples from 4 study participants were collected and analyzed for serum escitalopram concentrations. Two weeks post-RYGB, although there were minimal changes in each participants body mass index (<5%), drug concentrations were 33% (4%–71%) decreased as compared with presurgical serum concentrations. There were further decreases in drug concentrations 6 weeks postsurgery. All clinical laboratory values were within normal reference intervals. Conclusions: RYGB significantly alters the gastrointestinal tract and impacts escitalopram drug concentrations, even shortly after surgery.

The Benefits and Challenges of an Interfaced Electronic Health Record and Laboratory Information System: Effects on Laboratory Processes

CONTEXT - A recent government regulation incentivizes implementation of an electronic health record (EHR) with computerized order entry and structured results display. Many institutions have also chosen to interface their EHR with their laboratory information system (LIS). OBJECTIVE - To determine the impact of an interfaced EHR-LIS on laboratory processes. DESIGN - We analyzed several different processes before and after implementation of an interfaced EHR-LIS: the turnaround time, the number of stat specimens received, venipunctures per patient per day, preanalytic errors in phlebotomy, the number of add-on tests using a new electronic process, and the number of wrong test codes ordered. Data were gathered through the LIS and/or EHR. RESULTS - The turnaround time for potassium and hematocrit decreased significantly (P = .047 and P = .004, respectively). The number of stat orders also decreased significantly, from 40% to 7% for potassium and hematocrit, respectively (P < .001 for both). Even though the average number of inpatient venipunctures per day increased from 1.38 to 1.62 (P < .001), the average number of preanalytic errors per month decreased from 2.24 to 0.16 per 1000 specimens (P < .001). Overall there was a 16% increase in add-on tests. The number of wrong test codes ordered was high and it was challenging for providers to correctly order some common tests. CONCLUSIONS - An interfaced EHR-LIS significantly improved within-laboratory turnaround time and decreased stat requests and preanalytic phlebotomy errors. Despite increasing the number of add-on requests, an electronic add-on process increased efficiency and improved provider satisfaction. Laboratories implementing an interfaced EHR-LIS should be cautious of its effects on test ordering and patient venipunctures per day.

Age-Dependent Metabolic and Immunosuppressive Effects of Tacrolimus.

Immunosuppression in elderly recipients has been underappreciated in clinical trials. Here, we assessed age‐specific effects of the calcineurin inhibitor tacrolimus (TAC) in a murine transplant model and assessed its clinical relevance on human T cells. Old recipient mice exhibited prolonged skin graft survival compared with young animals after TAC administration. More important, half of the TAC dose was sufficient in old mice to achieve comparable systemic trough levels. TAC administration was able to reduce proinflammatory interferon‐γ cytokine production and promote interleukin‐10 production in old CD4+ T cells. In addition, TAC administration decreased interleukin‐2 secretion in old CD4+ T cells more effectively while inhibiting the proliferation of CD4+ T cells in old mice. Both TAC‐treated murine and human CD4+ T cells demonstrated an age‐specific suppression of intracellular calcineurin levels and Ca2+ influx, two critical pathways in T cell activation. Of note, depletion of CD8+ T cells did not alter allograft survival outcome in old TAC‐treated mice, suggesting that TAC age‐specific effects were mainly CD4+ T cell mediated. Collectively, our study demonstrates age‐specific immunosuppressive capacities of TAC that are CD4+ T cell mediated. The suppression of calcineurin levels and Ca2+ influx in both old murine and human T cells emphasizes the clinical relevance of age‐specific effects when using TAC.

The development and validation of a turbulent flow-liquid chromatography–tandem mass spectrometric method for the simultaneous quantification of citalopram, sertraline, bupropion and hydroxybupropion in serum

OBJECTIVES Depression is a rapidly growing issue in the United States. There are many drug classes that may be used to treat depression, including the selective serotonin-reuptake inhibitors (SSRIs) citalopram (Celexa®) and sertraline (Zoloft®), as well as the aminoketone bupropion (Wellbutrin®). However, therapeutic efficacy and treatment success is often variable, requiring changes in dosing regimens or drug selection. Methods for drug quantification can become important tools in the assessment of drug efficacy to optimize treatment regimens. Here, we present a turbulent flow-liquid chromatography-tandem mass spectrometric (TFC-MS/MS) method for the robust, simultaneous quantification of citalopram, sertraline, bupropion and its active metabolite, hydroxybupropion (OH-bupropion). DESIGN AND METHODS Serum spiked with the aforementioned antidepressants, along with their corresponding isotopically labeled internal standards was subjected to protein precipitation. Samples were injected onto a TFC column for on-line solid phase extraction and a Hypersil Gold C18 column for chromatographic separation. Detection was achieved using a TSQ Vantage mass spectrometer. Assay validation followed FDA bioanalytical guidelines. RESULTS The analytical measuring range for all analytes spanned from 5 to 1000ng/mL. Intra- and inter-assay precision across four quality control levels were ≤9.2% and ≤14.8%, respectively. A comparison to other LC-MS/MS methods resulted in a strong correlation with correlation coefficients ranging from 0.9929 to 0.9971. Carryover, stability, recovery, matrix effects, extraction and processing efficiency were also deemed acceptable in accordance with FDA recommendations. CONCLUSIONS The development and validation of this TFC-MS/MS method allow for the robust and high-throughput quantification of commonly prescribed antidepressants.

Significant Reduction in Preanalytical Errors for Nonphlebotomy Blood Draws After Implementation of a Novel Integrated Specimen Collection Module

OBJECTIVES Most preanalytical errors at our institution occur during nonphlebotomy blood draws. We implemented an electronic health record (EHR), interfaced the EHR to the laboratory information system, and designed a new specimen collection module. We studied the effects of the new system on nonphlebotomy preanalytical errors. METHODS We used an electronic database of preanalytical errors and calculated the number and type of the most common errors in the emergency department (ED) and inpatient nursing for 3-month periods before (August-October 2014) and after (August-October 2015) implementation. The level of staff compliance with the new system was also assessed. RESULTS The average monthly preanalytical errors decreased significantly from 7.95 to 1.45 per 1,000 specimens in the ED (P < 0001) and 11.75 to 3.25 per 1,000 specimens in inpatient nursing (P < 0001). The rate of decrease was similar for mislabeled, unlabeled, wrong specimen received and no specimen received errors. Most residual errors (80% in the ED and 67% in inpatient nursing) occurred when providers did not use the new system as designed. CONCLUSIONS Implementation of a customized specimen collection module led to a significant reduction in preanalytical errors. Improved compliance with the system may lead to further reductions in error rates.

Fluctuating creatinine in the cardiac unit.

BACKGROUND Inconsistent serum creatinine results were observed in a patient with a history of λ light-chain (AL) amyloidosis with multiple comorbidities, including renal nephropathy. Throughout admission, serum creatinine concentrations varied and were inconsistent with the patients clinical presentation. Studies were conducted to elucidate the cause of the observed fluctuations. METHODS Whole blood plasma and serum samples were assessed using alternate methodologies and confirmed a falsely low creatinine concentration when analyzed using an enzymatic methodology. A review of the patients chart identified a potential interfering substance, which was verified via spiking studies. A review of the specimen collection practices was also conducted to understand the intermittently low creatinine values. RESULTS Upon admission, the patients serum creatinine concentration was 1.7mg/dl. However, creatinine values varied from 0.6 to 1.9mg/dl in the proceeding days, and the low creatinine concentrations were inconsistent with the patients clinical presentation. To investigate, paired specimens were collected for whole blood plasma analysis via amperometric detection and serum analysis using either enzymatic or Jaffe methodologies. Enzymatic measurement of creatinine resulted in a lower creatinine concentration (0.6mg/dl) as compared to kinetic Jaffe or whole blood testing (1.8mg/dl). Following consultation with the clinical team, the patient had been administered dopamine intravenously in the days following admission. Studies illustrated dopamine concentrations above 6.50×10(5)pg/ml resulted in decreased creatinine concentrations when measured enzymatically. The intermittent low creatinine concentrations observed were due to collection via a peripherally inserted central catheter line. CONCLUSION Fluctuations in serum creatinine concentrations in a hospitalized patient were due to interference by dopamine. Samples collected from a peripherally inserted central catheter line in which dopamine was administered resulted in the suppression of peroxidase assays that use phenazone as a substrate.

Monitoring opioid and benzodiazepine use and abuse: Is oral fluid or urine the preferred specimen type?

BACKGROUND Oral fluid (OF) has become an increasingly popular matrix to assess compliance in pain management and addiction settings as it reduces the likelihood of adulteration. However, drug concentrations and windows of detection are not as well studied in OF as in urine (UR). We compared the clinical utility and analytical performance of OF and UR as matrices for detecting common benzodiazepines and opioids. METHODS OF and UR concentrations of 5 benzodiazepines and 7 opioids were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 263 paired OF and UR specimens. UR creatinine was measured and prescription medications were reviewed. RESULTS The benzodiazepines 7-aminoclonazepam, lorazepam, and oxazepam exhibited statistically higher detection rates in UR. For opioids, 6-AM was statistically more likely to be detected in OF, while hydromorphone and oxymorphone were statistically more likely to be detected in UR. Chemical properties including glucuronidation explain preferential detection in each matrix, not UR creatinine nor prescription status. CONCLUSION We found that OF is the preferred matrix for 6-AM, while UR is preferred for 7-aminoclonazepam, lorazepam, oxazepam, hydromorphone, and oxymorphone. However, OF should be considered if the risk of adulteration is high and use and/or misuse of benzodiazepines, hydromorphone, and oxymorphone is low.

A rapid UPLC-MS/MS assay for the simultaneous measurement of fluconazole, voriconazole, posaconazole, itraconazole, and hydroxyitraconazole concentrations in serum

Abstract Background: Triazole antifungals are essential to the treatment and prophylaxis of fungal infections. Significant pharmacokinetic variability combined with a clinical need for faster turnaround times has increased demand for in-house therapeutic drug monitoring of these drugs, which is best performed using mass spectrometry-based platforms. However, technical and logistical obstacles to implementing these platforms in hospital laboratories have limited their widespread utilization. Here, we present the development and validation of a fast and simple ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to measure fluconazole, voriconazole, posaconazole, itraconazole, and hydroxyitraconazole in human serum suitable for incorporation into a hospital clinical laboratory. Methods: Serum samples (20 µL) were prepared using protein precipitation in the presence of deuterated internal standards. Chromatographic separation was accomplished using reversed phase UPLC and analysis was performed using positive-mode electrospray ionization and collision-induced dissociation MS. Results: Total analytical run time was 3 min. All analytes demonstrated linearity (r2>0.998) from 0.1 to 10 µg/mL (1–100 µg/mL for fluconazole), acceptable accuracy and precision (%DEV<15% and %CV<15% at all levels tested), suitable stability under relevant storage conditions, and correlated well with reference laboratory results. Conclusions: A simple and rapid UPLC-MS/MS method for monitoring multiple triazole antifungals was developed with a focus on the needs of hospital laboratories. The assay is suitable for clinical utilization and management of patients on these medications.

Increased Patient Satisfaction and a Reduction in Pre-Analytical Errors Following Implementation of an Electronic Specimen Collection Module in Outpatient Phlebotomy

Background Patient satisfaction in outpatient phlebotomy settings typically depends on wait time and venipuncture experience, and many patients equate their experiences with their overall satisfaction with the hospital. Methods We compared patient service times and preanalytical errors pre- and postimplementation of an integrated electronic health record (EHR)-laboratory information system (LIS) and electronic specimen collection module. We also measured patient wait time and assessed patient satisfaction using a 5-question survey. Results The percentage of patients waiting less than 10 minutes increased from 86% preimplementation to 93% postimplementation of the EHR-LIS (P ≤.001). The median total service time decreased significantly, from 6 minutes (IQR, 4-8 minutes), to 5 minutes (IQR, 3-6 minutes) (P = .005). The preanalytical errors decreased significantly, from 3.20 to 1.93 errors per 1000 specimens (P ≤.001). Overall patient satisfaction improved, with an increase in excellent responses for all 5 questions (P ≤.001). Conclusions We found several benefits of implementing an electronic specimen collection module, including decreased wait and service times, improved patient satisfaction, and a reduction in preanalytical errors.