Biological Testing and Interpretation of Laboratory Results Associated with Detecting Newborns with Substance Exposure.

BACKGROUND: Substance use during pregnancy is common, as is biological testing that is intended to help identify prenatal exposures. However, there is no standardized requirement for biological testing with either maternal or newborn specimens, nor is there standardization related to when testing occurs, how frequently testing occurs, what specimen(s) to test, what substances to test for, or how to perform testing. CONTENT: We review common specimen types tested to detect maternal and newborn substance exposure with a focus on urine, meconium, and umbilical cord tissue. We also review common analytical methods used to perform testing, including immunoassay, and mass spectrometry platforms. Considerations regarding the utilization of testing relative to the purpose of testing, the drug analyte(s) of interest, the specific testing employed, and the interpretation of results are emphasized to help guide decisions about clinical utilization of testing. We also highlight specific examples of unexpected results that can be used to guide interpretation and appropriate next steps. SUMMARY: There are strengths and limitations associated with all approaches to detecting substance exposure in pregnant persons as well as biological testing to evaluate a newborn with possible substance exposure. Standardization is needed to better inform decisions surrounding evaluation of substance exposures in pregnant people and newborns. If biological sampling is pursued, testing options and results must be reviewed in clinical context, acknowledging that false-positive and -negative results can and do occur.

Distribution of videos demonstrating best practices in preventing hemolysis is associated with reduced hemolysis among nurse-collected specimens in hospitals.

BACKGROUND: Minimizing hemolysis during phlebotomy ensures accurate chemistry results and reduces test cancellations and specimen recollections. We developed videos demonstrating best practices to reduce hemolysis and tested whether distribution to clinical nurse educators (CNEs) for provision to nursing staff affected the degree of specimen hemolysis in hospital inpatient units and outpatient clinics. METHODS: Videos of common blood collections demonstrating best practices to reduce hemolysis were filmed and then distributed via email link to all hospital-based CNEs in Calgary, Alberta, Canada. (https://vimeo.com/user18866730/review/159869683/a0cec9827f). Roche Cobas hemolysis index (H-index) results from specimens collected +/- 12 months from the date of video distribution were extracted from Roche Cobas IT middleware (cITM) and linked to collection location. An interrupted time series (ITS) analysis with collection location as the unit of anlaysis was used to quantify impact of video distribution on the trajectory of weekly mean log-H-index weighted by inverse variance. RESULTS: In +/- 3 months of data flanking video distribution (n = 137 241 collections), where overall impact was strongest, H-index trajectory (change in units per week) decreased immediately following video distribution (-5.7% / week, p < 0.01). This was accompanied by a 22% drop in overall H-index from the week before to the week after video distribution (y-intercept change, or gap). There was also a small but significant overall decrease in the proportion of hemolyzed specimens (-0.3%, p < 0.01). These changes were not observed at all collection locations, and in fact increases occured at some locations. CONCLUSIONS: We developed a novel and convenient educational aid that, when distributed, was associated with beneficial changes in specimen hemolysis at hospital inpatient units and outpatient clinics. Including it in ongoing nursing education will fill a knowledge gap that may help to reduce specimen hemolysis.

Providers' Perspectives Related to Parents' Choice of Pediatric Provider of Record and Newborn Screening: A Qualitative Study.

The pediatric provider of record has a significant role in newborn screening and maintaining infant health after birth. Procedural errors and delays in communication can hinder the identification of infants with critical illnesses or follow up of unsatisfactory NBS samples. For this study, key stakeholders, including nurses, physicians, and midwives were interviewed to understand how the pediatric provider of record is selected by parents and examine factors affecting the newborn screening education and processes in the perinatal period. Provider responsibilities, timing of parent education, and social determinants of health played a role in parents' choices of the pediatric provider. Investment in future intervention programs is needed for reducing the number of infants without a designated pediatric provider of record. Research is needed to understand social complexities and healthcare systems which affect parents' choices of pediatric providers and newborn screening processes to optimize clinical outcomes for infants.

Biological variation in clozapine and metabolite reporting during therapeutic drug monitoring.

BACKGROUND: Clozapine (CLO) is an atypical antipsychotic used in management of treatment-resistant schizophrenia. Adverse drug reactions are caused by both CLO and its primary metabolite, norclozapine (NCLO). We defined the biological variability of CLO, NCLO, and the CLO to NCLO ratio (CNR) as well as assess the impact of reporting CLO and NCLO routinely. METHODS: The CVi and CVg were calculated from 1904 results from 247 patients by CV-ANOVA, and ANOVA, respectively, for CLO, NCLO, and the CNR. Association between each were also analyzed against a number of parameters including age and gender, complete blood count (CBC), kidney and liver function tests, lipids, and glucose within 24 h of CLO measurement. RESULTS: For CLO, NCLO and CNR, the CVi was calculated as 19.3%, 19.2%, and 14.7%, and the CVg was 46.9%, 51.4%, and 36.3%, respectively. A total of 87 patients (19.7%) demonstrated higher NCLO results than CLO, with a ratio as low as 0.47. Kidney function was also found to have a statistically significant relationship to CLO and NCLO levels. CONCLUSIONS: We provide data for biological variability of CLO metabolism as well as while providing some evidence for reporting NCLO values clinically.

Updated reference intervals for urine normetanephrine have no effect on test sensitivity but fewer false positives.

OBJECTIVE: We previously highlighted the problem of frequent false positives in 24 h urine normetanephrine(UNM) measurements owing to reference intervals that are inappropriately low for the population being screened for pheochromocytoma. Using a large population database, we devised new age-stratified reference intervals for the 24 h UNM test that were higher compared to previous. However, it was uncertain as to whether this would compromise test sensitivity for true pheochromocytoma cases. DESIGN AND METHODS: Retrospective analysis of all pheochromocytoma cases from a recently constructed provincial registry. All confirmed cases had their diagnostic UNM results retrospectively re-analysed according to the newly proposed UNM reference intervals to determine the percentage and phenotype of cases that might have been theoretically missed with the new reference range. RESULTS: After excluding pediatric and non-secretory head and neck paragangliomas, there were 60 confirmed pheochromocytoma cases. Using prior reference intervals, 51/60 (85%) had an abnormally high UNM. Of the 9 with normal UNM, 4 had a high urine metanephrine(UMN), 5 had normal levels of both UNM and UMN such that 55/60 had abnormal test results, representing the historical combined test sensitivity of 92%. Using the proposed reference interval, 43/60 (72%) had high UNM results. Of the 17 with normal UNM, 12 had high UMN, 5 had normal levels of both UNM and UMN. Therefore, 55/60 patients had had elevations in either UNM or UMN, corresponding to an identical combined test sensitivity of 92%. CONCLUSIONS: Reference intervals for UNM derived from actual clinical population screening data are higher than in traditional healthy volunteers. Use of these more appropriate reference intervals can significantly reduce the false positive rate without compromising test sensitivity for true pheochromocytoma.

Measuring steroids from dried blood spots using tandem mass spectrometry to diagnose congenital adrenal hyperplasia.

BACKGROUND: Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders that occur due to defects in the steroidogenesis pathway. Approximately 90% of CAH cases can be diagnosed by the measurement of serum 17-hydroxyprogesterone alone. However, the quantification of six additional steroids could significantly improve CAH laboratory diagnosis. Using dried blood spot (DBS) as specimen of choice can further improve patient care due to the small sample volume required for CAH diagnosis in neonates. METHODS: An optimized DBS sample preparation method was employed for steroids quantification without the need of derivatization. A LC-MS/MS assay was developed and optimized using a reverse phase-ultra high-pressure liquid chromatography (RP-UHPLC) system combined with triple quadrupole mass spectrometry using positive electrospray ionization mode. RESULTS: The assay was validated according to CLSI analytical guidelines, including lower limit of quantification (LLOQ), linearity, precision, accuracy, carryover, and method comparison. The analytical measuring range of the method for all steroids was 2.5, 5, or 10 ng/ml to 250 ng/ml in DBS, r2 ≥ 0.995. The LLOQ, intra-day and inter-day precision were 0.11-1.8 ng/ml, 1.2-6.4 ng/ml, 1.8-11.5%, and 5.3-13.8%, respectively. CONCLUSIONS: Our LC-MS/MS assay simultaneously detects 7 steroids for the diagnosis of CAH and can be readily implemented in clinical laboratories to provide superior analytical performance over traditional immunoassays.

Inpatient Measurements of Urine Metanephrines are Indistinguishable from Pheochromocytoma: Retrospective Cohort Study.

BACKGROUND: Pheochromocytoma is a rare cause of acute cardiovascular disease; however, any severe illness may have high catecholamines, simulating pheochromocytoma. We determined the spectrum of urine metanephrines from inpatient and outpatient collections without pheochromocytoma, compared with confirmed pheochromocytoma patients. METHODS: Retrospective analysis using centralized laboratory data serving all outpatients and hospitals in southern Alberta. The analysis comprised 24-hour urine normetanephrine and metanephrine (UNM-UMN) results collected from hospital inpatients, community outpatients, and patients from a comprehensive provincial pheochromocytoma registry. RESULTS: There were 974 unique inpatients (including 132 from intensive care), 6802 outpatients, and 58 pheochromocytoma patients. Among outpatient, general ward, and intensive care unit (ICU) patients, 18.7%, 34.4%, and 67.4% of results, respectively, were supranormal. Although pheochromocytoma patients had higher median UNM-UMN vs inpatients, there was substantial overlap. Receiver operating characteristic (ROC) analysis showed area under the curve (AUC) of 0.64-0.91 to detect true pheochromocytoma (P < .0001), with progressively poorer discrimination among hospitalized and ICU-dependent patients. A 24-hour urine normetanephrine >6.95 nmol/d had 98% specificity for pheochromocytoma when inpatient general ward samples were included, but only 46% sensitivity and 13% positive predictive value for pheochromocytoma. Considering ICU collections, 98% specificity required results more than fivefold above the upper reference limit and still had poor positive predictive value. A model combining both UNM and UMN results as a cross-product marginally improved the ROC AUC, but improved sensitivity in outpatients and ward patients but not ICU patients. CONCLUSION: There is a high degree of overlap in UNM-UMN between hospitalized patients and pheochromocytoma; high test specificity is not achieved in this population unless >3-5 times the upper reference limit.

Properly Collected Plasma Metanephrines Excludes PPGL After False-Positive Screening Tests.

CONTEXT: False-positive results are common for pheochromocytoma/paraganglioma (PPGL) real-world screening. OBJECTIVE: Determine the correlation between screening urine and seated plasma metanephrines in outpatients where PPGL was absent, compared to meticulously prepared and supine-collected plasma metanephrines with age-adjusted references. DESIGN: Retrospective cohort study. SETTING: Databases from a single-provider provincial laboratory (2012-2018), a validated PPGL registry, and a manual chart review from a specialized endocrine testing unit. PATIENTS: PPGL registry data excluded known PPGL cases from the laboratory database. Outpatients having both urine and plasma metanephrines <90 days apart. METHODS: The correlation between urine and seated plasma measures along with the total positivity rate. All cases of plasma metanephrines drawn in the endocrine unit were reviewed for test indication and test positivity rate. RESULTS: There were 810 non-PPGL pairs of urine and plasma metanephrines in the laboratory database; 46.1% of urine metanephrines were reported high. Of seated outpatient plasma metanephrines drawn a median of 5.9 days later, 19.2% were also high (r = 0.33 and 0.50 for normetanephrine and metanephrine, respectively). In contrast, the meticulously prepared and supine collected patients (n = 139, 51% prior high urine metanephrines) had <3% rate of abnormal high results in patients without known PPGL/adrenal mass. CONCLUSIONS: There was a poor-to-moderate correlation between urine and seated plasma metanephrines. Up to 20% of those with high urine measures also had high seated plasma metanephrines in the absence of PPGL. Properly prepared and collected supine plasma metanephrines had a false-positive rate of <3% in the absence of known PPGL/adrenal mass.

Epidemiology of pheochromocytoma and paraganglioma: population-based cohort study.

OBJECTIVE: Despite the significant morbidity and mortality associated with pheochromocytoma and paraganglioma, little is known about their epidemiology. The primary objective was to determine the incidence of pheochromocytoma and paraganglioma in an ethnically diverse population. A secondary objective was to develop and validate algorithms for case detection using laboratory and administrative data. DESIGN: Population-based cohort study in Alberta, Canada from 2012 to 2019. METHODS: Patients with pheochromocytoma or paraganglioma were identified using linked administrative databases and clinical records. Annual incidence rates per 100 000 people were calculated and stratified according to age and sex. Algorithms to identify pheochromocytoma and paraganglioma, based on laboratory and administrative data, were evaluated. RESULTS: A total of 239 patients with pheochromocytoma or paraganglioma (collectively with 251 tumors) were identified from a population of 5 196 368 people over a period of 7 years. The overall incidence of pheochromocytoma or paraganglioma was 0.66 cases per 100 000 people per year. The frequency of pheochromocytoma and paraganglioma increased with age and was highest in individuals aged 60-79 years (8.85 and 14.68 cases per 100 000 people per year for males and females, respectively). An algorithm based on laboratory data (metanephrine >two-fold or normetanephrine >three-fold higher than the upper limit of normal) closely approximated the true frequency of pheochromocytoma and paraganglioma with an estimated incidence of 0.54 cases per 100 000 people per year. CONSLUSION: The incidence of pheochromocytoma and paraganglioma in an unselected population of western Canada was unexpectedly higher than rates reported from other areas of the world.

Moderate renal impairment does not preclude the accuracy of 24-hour urine normetanephrine measurements for suspected pheochromoctyoma.

OBJECTIVE: A 24-hour urine nor/metanephrine (urine NM-MN) measurements are a recommended first step in pheochromocytoma diagnosis. We hypothesized the presence of renal impairment (CKD) significantly confounds the results obtained in a urine NM-MN collection, giving artificially lower measurements. DESIGN: Retrospective review of a comprehensive laboratory database with all urine NM-MN results from Southern Alberta from 2010 to 2018 (n = 15 505). After excluding high probability pheochromocytoma cases, results from patients with three levels of CKD (n = 796) were compared to those without CKD to determine the potential CKD effect. PATIENTS: All patients having urine NM-MN collection during the time period, irrespective of ordering physician or test indication. MEASUREMENTS: Urine NM-MN was measured by liquid chromatography-tandem mass spectrometry and glomerular filtration rate determined within a median of 1.9 days, as estimated by CKD-EPI equation. RESULTS: In subjects with mild-to-moderate renal impairment, there was no continuous gradient between subnormal renal function and urine NM-MN measures. When the estimated GFR was < 15 mL/min/m2 , the hypothesized effect on lowered urine NM-MN became apparent. CONCLUSIONS: A 24-hour urine NM-MN measurement is unlikely to be affected by mild-to-moderate renal impairment and may be used as a reliable diagnostic test. With more advanced renal impairment, CKD-specific reference ranges or an alternative test may be needed.

A high rate of modestly elevated plasma normetanephrine in a population referred for suspected PPGL when measured in a seated position.

OBJECTIVE: Determine rate of high plasma normetanephrine or metanephrine (PNM-PMN) in a large sample of patients according to PNM-PMN posture and age-adjusted references. DESIGN: Retrospective re-analysis of PNM-PMN from a Canadian reference laboratory (n = 5452), 2011-2015; most were in seated position (n = 5112) rather than supine (n = 340). An international PPGL database demonstrated expected distribution of supine PNM-PMN in PPGL patients. METHODS: All PNM-PMN from a tertiary referral laboratory were reviewed. Any PNM-PMN result greater than 2× upper reference limit (URL) was considered likely true PPGL. Results 1-2× URL were uncertain, requiring additional testing/follow-up despite most being false positive given the rarity of PPGL. The rate of results in the 1-2× URL category were calculated for each group according to collection posture and differing published URL: seated, supine or supine age adjusted. RESULTS: When collected and interpreted by seated URL, 19.6% of PNM required additional testing; only 4.6% being >2× URL. For patients over age 50 years, the abnormal rate was 24.9%. When collected supine, interpreted by supine age-adjusted URL, only 5.3% of PNM were mildly elevated. Possible false positives may be even lower when considering PMN or plasma methoxytyramine which were commonly high in true PPGL despite mild PNM elevations. CONCLUSIONS: In a general medical population, seated PNM has a high rate of abnormal results, far exceeding expected prevalence. Supine measurement with supine, age-adjusted interpretation is strongly preferred prior to costly or invasive PPGL investigations. SUMMARY: Review of 5452 plasma normetanephrine measurements showed 20% to be high, likely false positives for most. Supine, age-adjusted measures were half as likely to be elevated.

Concordance between laboratories in metal ion testing in patients with metal-on-metal hip implants.

BACKGROUND: Testing of whole blood or serum metal ion levels has become an important part of assessing and monitoring the performance of metal-on-metal bearings, both in hip resurfacing arthroplasty and in total hip replacement. The aim of this study was to determine the concordance between 2 laboratories testing cobalt and chromium ion levels in patients with metal-on-metal bearings. METHODS: Serum and whole blood samples from patients who had undergone metal-on-metal resurfacing or large-diameter total hip arthroplasty were tested for cobalt and chromium ions in laboratory A (a recognized laboratory) and laboratory B (tasked with testing clinical specimens). Laboratory A performed cobalt and chromium testing on whole blood, and laboratory B performed cobalt testing on whole blood and chromium testing on serum. RESULTS: Samples from 104 patients were tested. Laboratory B reported lower whole blood cobalt levels than laboratory A. Furthermore, laboratory A reported that all patients had elevated whole blood cobalt ion levels compared to the normal reference values for the laboratory, whereas laboratory B reported that 46 patients (44.2%) had whole blood cobalt ion levels within the normal reference range for the laboratory. CONCLUSION: This comparative study highlights the importance of using a single laboratory for metal ion testing, as values generated from different laboratories may not be directly comparable. With recent literature suggesting that whole blood cobalt levels as low as 1 ppb may be a predictor of adverse reactions to metal debris, accurate clinical measurement needs to be increasingly exact.

CONTEXTE: Le dosage sanguin ou sérique d'ions métalliques est devenu une étape importante de l'évaluation et du suivi des prothèses à couple de frottement métal-métal utilisées en arthroplastie de resurfaçage ou totale de la hanche. La présente étude visait à évaluer la concordance entre les résultats de 2 laboratoires pour le dosage du cobalt et du chrome chez des patients porteurs de ces prothèses. MÉTHODES: Des prélèvements de sérum et de sang entier de patients porteurs d'une prothèse de resurfaçage ou d'une prothèse totale à grand diamètre de hanche à couple métal-métal ont été expédiés au laboratoire A (un laboratoire reconnu) et au laboratoire B (spécialisé en analyse d'échantillons cliniques) pour le dosage des ions cobalt et chrome. Le laboratoire A a effectué toutes ses analyses sur des prélèvements de sang entier, et le laboratoire B a utilisé le sang entier pour le dosage du cobalt et le sérum pour le dosage du chrome. RÉSULTATS: Les prélèvements de 104 patients ont été analysés. Le laboratoire B a détecté des taux sanguins de cobalt inférieurs à ceux du laboratoire A. De plus, le laboratoire A a indiqué que tous les patients présentaient des taux de cobalt sanguins élevés par rapport à ses valeurs de référence, alors que le laboratoire B a déterminé que le taux de cobalt sanguin de 46 patients (44,2 %) se trouvait dans sa fourchette de valeurs de référence normales. CONCLUSION: Cette étude comparative vient souligner l'importance de choisir un seul laboratoire pour le dosage des ions métalliques, car les valeurs générées par des établissements différents pourraient ne pas être directement comparables. Comme des études récentes semblent indiquer que des taux de cobalt sanguins aussi faibles que 1 p. p. milliard pourraient être des prédicteurs de réaction indésirable aux débris métalliques, la précision et l'exactitude des mesures cliniques revêtent une importance croissante.

Efficacy of orthotic devices for increased active proximal interphalangeal extension joint range of motion: A systematic review.

STUDY DESIGN: Systematic review. INTRODUCTION/PURPOSE OF THE STUDY: To determine the efficacy of orthotic devices for increased active proximal interphalangeal (PIP) joint range of motion and optimal wearing schedule of the devices to guide clinical practice. The secondary purpose is to capture the outcome measures used by the authors. The final purpose was to determine if recent studies addressed patient satisfaction and adherence in the orthotic management of a PIP joint injury. METHODS: A comprehensive literature search was conducted using the search terms splint, orthotic device, hand orthotic, brace, proximal interphalangeal joint, occupational therapy, and physical therapy using PubMed, CINAHL, MEDLINE, and ProQuest. The following data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines: background statement, objectives, data sources, study eligibility criteria, participants, and interventions, study appraisal and synthesis methods, results, limitations, conclusions, and implications of key findings. RESULTS: Best results were achieved when the PIP orthoses were worn for a longer duration especially for the treatment of extension deficits. DISCUSSION: Studies that provided a wearing schedule of a minimum of 6 hours obtained the greatest improvements in extension deficits of the PIP joint. CONCLUSION: Recommended orthotic dosage to treat PIP joint injury is at least 6 hours a day for 8-17 weeks.

Disruption of Angiogenesis by Anthocyanin-Rich Extracts of Hibiscus sabdariffa.

Abnormal vessel formations contribute to the progression of specific angiogenic diseases including age-related macular degeneration. Adequate vessel growth and maintenance represent the coordinated process of endothelial cell proliferation, matrix remodeling, and differentiation. However, the molecular mechanism of the proper balance between angiogenic activators and inhibitors remains elusive. In addition, quantitative analysis of vessel formation has been challenging due to complex angiogenic morphology. We hypothesized that conjugated double bond containing-natural products, including anthocyanin extracts from Hibiscus sabdariffa, may control the proper angiogenesis. The current study was designed to determine whether natural molecules from African plant library modulate angiogenesis. Further, we questioned how the proper balance of anti- or pro-angiogenic signaling can be obtained in the vascular microenvironment by treating anthocyanin or fatty acids using chick chorioallantoic membrane angiogenesis model in ovo. The angiogenic morphology was analyzed systematically by measuring twenty one angiogenic indexes using Angiogenic Analyzer software. Chick chorioallantoic model demonstrated that anthocyanin-rich extracts inhibited angiogenesis in time- and concentration-dependent manner. Molecular modeling analysis proposed that hibiscetin as a component in Hibiscus may bind to the active site of vascular endothelial growth factor receptor 2 (VEGFR2) with ΔG= -8.42 kcal/mol of binding energy. Our results provided the evidence that anthocyanin is an angiogenic modulator that can be used to treat uncontrolled neovascular-related diseases, including age-related macular degeneration.

One-step extraction and quantitation of toxic alcohols and ethylene glycol in plasma by capillary gas chromatography (GC) with flame ionization detection (FID).

OBJECTIVES: Clinical analysis of volatile alcohols (i.e. methanol, ethanol, isopropanol, and metabolite acetone) and ethylene glycol (EG) generally employs separate gas chromatography (GC) methods for analysis. Here, a method for combined analysis of volatile alcohols and EG is described. DESIGN AND METHODS: Volatile alcohols and EG were extracted with 2:1 (v:v) acetonitrile containing internal standards (IS) 1,2 butanediol (for EG) and n-propanol (for alcohols). Samples were analyzed on an Agilent 6890 GC FID. The method was evaluated for precision, accuracy, reproducibility, linearity, selectivity and limit of quantitation (LOQ), followed by correlation to existing GC methods using patient samples, Bio-Rad QC, and in-house prepared QC material. RESULTS: Inter-day precision was from 6.5-11.3% CV, and linearity was verified from down to 0.6mmol/L up to 150mmol/L for each analyte. The method showed good recovery (~100%) and the LOQ was calculated to be between 0.25 and 0.44mmol/L. Patient correlation against current GC methods showed good agreement (slopes from 1.03-1.12, and y-intercepts from 0 to 0.85mmol/L; R(2)>0.98; N=35). Carryover was negligible for volatile alcohols in the measuring range, and of the potential interferences tested, only toluene and 1,3 propanediol interfered. The method was able to resolve 2,3 butanediol, diethylene glycol, and propylene glycol in addition to the peaks quantified. CONCLUSIONS: Here we describe a simple procedure for simultaneous analysis of EG and volatile alcohols that comes at low cost and with a simple liquid-liquid extraction requiring no derivitization to obtain adequate sensitivity for clinical specimens.

Developing optimized automated rule sets for reporting hemolysis, icterus and lipemia based on a priori outcomes analysis.

BACKGROUND: There is limited information about the effects of instituting CLSI Document C56A recommended workflows for the automated detection of hemolysis, lipemia and icterus (HIL) in different clinical laboratories and patient populations. We describe a process to develop and tailor automated reporting rules that are appropriate for the local laboratory population. METHODS: Automated decision algorithms were generated and applied to 2 high volume labs serving community and hospital populations. Proposed rules were applied to the datasets offline to predict the outcomes, and then were further optimized prior to implementation. RESULTS: Introduction of automated serum indices decreased HIL flagging compared to manual flagging. Hemolysis flagging was the greatest in all 3 patient populations, and was successfully reduced for LD, CK and AST by optimized rules that incorporated both the H-index result and the analyte result. Changes in flagging rates were also patient population specific, particularly for icterus which was a problem in hospitalized populations but not in the community. Overall, concordance between manual and automated flagging methods was very low in both laboratories. CONCLUSIONS: We demonstrate that flagging algorithms may not be universally transferable due to lab specific and population specific factors and demonstrate the benefits of local, a priori testing of algorithms prior to implementation.

Direct large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry determination of artificial sweeteners sucralose and acesulfame in well water.

Acesulfame (ACE) and sucralose (SUC) have become recognized as ideal domestic wastewater contamination indicators. Liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis is commonly used; however, the sensitivity of SUC is more than two orders of magnitude lower than that of ACE, limiting the routine monitoring of SUC. To address this issue, we examined the ESI behavior of both ACE and SUC under various conditions. ACE is ionic in aqueous solution and efficiently produces simple [M-H](-) ions, but SUC produces multiple adduct ions, limiting its sensitivity. The formic acid (FA) adducts of SUC [M+HCOO](-) are sensitively and reproducibly generated under the LC-MS conditions. When [M+HCOO](-) is used as the precursor ion for SUC detection, the sensitivity increases approximately 20-fold compared to when [M-H](-) is the precursor ion. To further improve the limit of detection (LOD), we integrated the large volume injection approach (500µL injection) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), which reduced the method detection limit (MDL) to 0.2ng/L for ACE and 5ng/L for SUC. To demonstrate the applicability of this method, we analyzed 100 well water samples collected in Alberta. ACE was detected in 24 wells at concentrations of 1-1534ng/L and SUC in 8 wells at concentrations of 65-541ng/L. These results suggest that wastewater is the most likely source of ACE and SUC impacts in these wells, suggesting the need for monitoring the quality of domestic well water.

Identification of tobacco-specific nitrosamines as disinfection byproducts in chloraminated water.

Tobacco-specific nitrosamines (TSNAs) exist in environmental waters; however, it is unknown whether TSNAs can be produced during water disinfection. Here we report on the investigation and evidence of TSNAs as a new class of disinfection byproducts (DBPs). Using five common TSNAs, including (methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as the targets, we first developed a solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method capable of rapidly determining these TSNAs at levels as low as 0.02 ng/L in treated water. Using this highly sensitive method, we investigated the occurrence and formation potential (FP) (precursor test conducted in the presence of chloramines) of TSNAs in treated water from two wastewater treatment plants (WWTPs) and seven drinking water treatment plants (DWTPs). NNAL was detected in the FP samples, but not in the samples before the FP test, confirming NNAL as a DBP. NNK was detected in the treated wastewater before the FP test, but its concentration increased significantly after chloramination in two of three tests. Thus, NNK could be a DBP and/or a contaminant in wastewater. Moreover, these TSNAs were detected in FP tests of wastewater-impacted DWTP plant influents in 9 of 11 samples. However, TSNAs were not detected at full-scale DWTPs, except for at one DWTP with high ammonia where breakpoint chlorination was not achieved. The concentration of the sum of five TSNAs (0.3 ng/L) was 100-fold lower than NDMA, suggesting that TSNAs have a minor contribution to total nitrosamines in water. We examined several factors in the treatment process and found that chlorine or ozone may destroy TSNA precursors and granular activated carbon (GAC) treatment may remove the precursors. Further research is warranted into the efficiency of these processes at different DWTPs using sources of varying water quality.