Efficacy, safety, and tolerability of plecanatide in patients with irritable bowel syndrome with constipation: results of two phase 3 randomized clinical trials.

OBJECTIVES: Two identical, phase 3, randomized, double-blind, placebo-controlled trials evaluated the efficacy and safety of plecanatide in patients with irritable bowel syndrome with constipation (IBS-C). METHODS: Adults meeting Rome III criteria for IBS-C were randomized (1:1:1) to placebo or plecanatide (3 or 6 mg) for 12 weeks. The primary efficacy end point was the percentage of overall responders (patients reporting ≥30% reduction from baseline in worst abdominal pain plus an increase of ≥1 complete spontaneous bowel movement (CSBM)/week from baseline in the same week for ≥6 of 12 treatment weeks). Safety was assessed by adverse events (AEs). RESULTS: Overall, 2189 individuals were randomized across the two studies and 1879 completed the studies. Demographic and baseline characteristics were similar across treatment groups and between studies. The percentage of overall responders in Study 1 was 30.2% and 29.5% for plecanatide 3 and 6 mg, respectively, vs. 17.8% placebo (P < 0.001 for each dose vs. placebo), and in Study 2 was 21.5% (P = 0.009) and 24.0% (P < 0.001) for plecanatide 3 and 6 mg, respectively, compared to 14.2% for placebo. The percentage of sustained efficacy responders (overall responders plus weekly responders for ≥2 of last 4 weeks of the 12-week treatment period) was significantly greater for both doses of plecanatide vs. placebo across both studies. All secondary end points (stool frequency/consistency, straining, abdominal symptoms) showed statistically significant improvements compared with placebo. The most common AE was diarrhea (3 mg, 4.3%; 6 mg, 4.0%; placebo, 1.0%). Discontinuation due to diarrhea was infrequent (3 mg, 1.2%; 6 mg, 1.4%; placebo, 0). CONCLUSIONS: Plecanatide significantly improved both abdominal pain and constipation symptoms of IBS-C with minimal associated side effects and high levels of tolerability.

Streptococcal group A, C and G pharyngitis in school children: a prospective cohort study in Southern India.

Diagnosing streptococcal pharyngitis in children on the basis of clinical appearance and throat culture is complicated by high colonisation rates and by the ability of other pathogens to cause clinically similar disease. To characterise the epidemiology of Lancefield Group A, C and G ß-haemolytic streptococcus (GAS, GCS and GGS, respectively) in children, we conducted a 2-year prospective study of 307 school children between 7 and 11 years old. GGS and GAS were commonly identified organisms both for silent streptococcal colonisation and symptomatic sore throat, while GCS was uncommonly found. Streptococcal culture positivity at the time of clinical pharyngitis was estimated to reflect true streptococcal pharyngitis in only 26% of instances, with the frequency varying from 54% for children rarely colonised to 1% for children frequently colonised. Numerous GAS emm types were identified, including several types previously associated with severe pharyngitis (e.g. emm types 1, 3 and 28). No severe complications were seen in any child. These data suggest that the clinical diagnosis of streptococcal pharyngitis is likely to remain difficult and that treatment decisions will remain clouded by uncertainty. There remains a need for organism-specific rapid point-of-care streptococcal diagnostic tests and tests that can distinguish between streptococcal colonisation and disease.

Recurrent event data analysis with intermittently observed time-varying covariates.

Although recurrent event data analysis is a rapidly evolving area of research, rigorous studies on estimation of the effects of intermittently observed time-varying covariates on the risk of recurrent events have been lacking. Existing methods for analyzing recurrent event data usually require that the covariate processes are observed throughout the entire follow-up period. However, covariates are often observed periodically rather than continuously. We propose a novel semiparametric estimator for the regression parameters in the popular proportional rate model. The proposed estimator is based on an estimated score function where we kernel smooth the mean covariate process. We show that the proposed semiparametric estimator is asymptotically unbiased, normally distributed, and derives the asymptotic variance. Simulation studies are conducted to compare the performance of the proposed estimator and the simple methods carrying forward the last covariates. The different methods are applied to an observational study designed to assess the effect of group A streptococcus on pharyngitis among school children in India. Copyright © 2016 John Wiley & Sons, Ltd.

Fred Neufeld and pneumococcal serotypes: foundations for the discovery of the transforming principle.

During the first decade of the twentieth century, the German bacteriologist Fred Neufeld, later Director of the Robert Koch-Institute in Berlin, first described the differentiation of pneumococci into serotypes on the basis of type-specific antisera. This finding was essential for subsequent research at the Rockefeller Institute of Medical Research (RIMR) in New York, and elsewhere, aiming for the conquest of human pneumococcal pneumonia, including antiserum therapy, the discovery that the type-specific antigens were carbohydrates, and the development of effective multivalent pneumococcal polysaccharide vaccines. Moreover, on the basis of pneumococcal serotypes Fred Griffith, in 1928 in London, discovered pneumococcal transformation, and Oswald T. Avery and coworkers, in 1944 at RIMR, identified DNA as the transforming substance. This sequence of events, leading to today's knowledge that genes consist of DNA, was initiated by a farsighted move of Simon Flexner, first Director of the RIMR, who asked Neufeld to send his pneumococcal typing strains, thus setting the stage for pneumococcal research at RIMR. Here, we describe Fred Neufeld's contributions in this development, which have remained largely unknown.

Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity.

The maximum size of organisms has increased enormously since the initial appearance of life >3.5 billion years ago (Gya), but the pattern and timing of this size increase is poorly known. Consequently, controls underlying the size spectrum of the global biota have been difficult to evaluate. Our period-level compilation of the largest known fossil organisms demonstrates that maximum size increased by 16 orders of magnitude since life first appeared in the fossil record. The great majority of the increase is accounted for by 2 discrete steps of approximately equal magnitude: the first in the middle of the Paleoproterozoic Era (approximately 1.9 Gya) and the second during the late Neoproterozoic and early Paleozoic eras (0.6-0.45 Gya). Each size step required a major innovation in organismal complexity--first the eukaryotic cell and later eukaryotic multicellularity. These size steps coincide with, or slightly postdate, increases in the concentration of atmospheric oxygen, suggesting latent evolutionary potential was realized soon after environmental limitations were removed.

The evolutionary consequences of oxygenic photosynthesis: a body size perspective.

The high concentration of molecular oxygen in Earth's atmosphere is arguably the most conspicuous and geologically important signature of life. Earth's early atmosphere lacked oxygen; accumulation began after the evolution of oxygenic photosynthesis in cyanobacteria around 3.0-2.5 billion years ago (Gya). Concentrations of oxygen have since varied, first reaching near-modern values ~600 million years ago (Mya). These fluctuations have been hypothesized to constrain many biological patterns, among them the evolution of body size. Here, we review the state of knowledge relating oxygen availability to body size. Laboratory studies increasingly illuminate the mechanisms by which organisms can adapt physiologically to the variation in oxygen availability, but the extent to which these findings can be extrapolated to evolutionary timescales remains poorly understood. Experiments confirm that animal size is limited by experimental hypoxia, but show that plant vegetative growth is enhanced due to reduced photorespiration at lower O(2):CO(2). Field studies of size distributions across extant higher taxa and individual species in the modern provide qualitative support for a correlation between animal and protist size and oxygen availability, but few allow prediction of maximum or mean size from oxygen concentrations in unstudied regions. There is qualitative support for a link between oxygen availability and body size from the fossil record of protists and animals, but there have been few quantitative analyses confirming or refuting this impression. As oxygen transport limits the thickness or volume-to-surface area ratio-rather than mass or volume-predictions of maximum possible size cannot be constructed simply from metabolic rate and oxygen availability. Thus, it remains difficult to confirm that the largest representatives of fossil or living taxa are limited by oxygen transport rather than other factors. Despite the challenges of integrating findings from experiments on model organisms, comparative observations across living species, and fossil specimens spanning millions to billions of years, numerous tractable avenues of research could greatly improve quantitative constraints on the role of oxygen in the macroevolutionary history of organismal size.

Capsule and Sprinkle Formulations of Lubiprostone Are Not Biologically Similar in Patients with Functional Constipation.

INTRODUCTION: Lubiprostone capsules are approved for managing three different chronic constipation conditions. A "sprinkle" formulation may facilitate use in individuals with difficulty swallowing capsules. Our objective was to evaluate the bioequivalence, pharmacokinetics (PK), and bioavailability of lubiprostone sprinkles vs lubiprostone capsules, compared with placebo. METHODS: A 1-week randomized, placebo-controlled, double-blinded, bioequivalence study (study 302) and a single-dose PK and bioavailability crossover study (study 304) were conducted. In study 302, 522 subjects with chronic constipation were randomized to lubiprostone sprinkle 24 µg twice daily (BID), lubiprostone capsule 24 µg BID, or placebo. The primary efficacy endpoint was observed spontaneous bowel movement (SBM) counts (equivalence defined as showing the 90% confidence interval [CI] of the "between-group SBM ratio" to be contained within 0.8-1.25). Study 304 included two cohorts of healthy volunteers randomized to a single 48-µg lubiprostone dose, sprinkle, or capsule (n = 35) or to a single 48-µg sprinkle dose, in fed or fasted state (n = 14). RESULTS: Both lubiprostone formulations significantly improved SBM count (sprinkle, 4.82 ± 3.66, P = 0.002; capsule, 5.74 ± 3.79, P < 0.0001) vs placebo (3.68 ± 2.16), but equivalent efficacy was not demonstrated, with a 90% CI for the SBM count ratio of 0.69-0.95. Quantifiable PK data on lubiprostone were limited; however, overall exposure to the M3 metabolite was approximately 44% higher with sprinkles vs capsules under fasted conditions (geometric mean ratio 1.441 [90% CI, 1.166, 1.782]), and exposure with the sprinkle formulation was 11% lower in the fed state vs the fasted state (geometric mean ratio 0.888 [90% CI, 0.675, 1.168]). Both formulations were generally well tolerated. CONCLUSION: Despite the significant improvement in SBM counts vs placebo, the sprinkle formulation did not demonstrate bioequivalence to the capsule formulation in either pharmacodynamic or PK key parameters. TRIAL REGISTRATION: Study 302: ClinicalTrials.gov identifier, NCT03097861; https://www.clinicaltrials.gov/ct2/show/NCT03097861 ; Study 304: ClinicalTrials.gov identifier, NCT03010631; https://www.clinicaltrials.gov/ct2/show/NCT03010631 .

Nephrology visits and health care resource use before and after reporting estimated glomerular filtration rate.

CONTEXT: Laboratory reporting of estimated glomerular filtration rate (GFR) has been widely implemented, with limited evaluation. OBJECTIVE: To examine trends in nephrologist visits and health care resource use before and after estimated GFR reporting. DESIGN, SETTING, AND PATIENTS: Community-based cohort study (N = 1,135,968) with time-series analysis. Participants were identified from a laboratory registry in Alberta, Canada, and followed up from May 15, 2003, to March 14, 2007 (with estimated GFR reporting implemented October 15, 2004). MAIN OUTCOME MEASURE: Nephrologist visits and patient management. RESULTS: Following estimated GFR reporting, the rate of first outpatient visits to a nephrologist for patients with chronic kidney disease (CKD; estimated GFR <60 mL/min/1.73 m(2)) increased by 17.5 (95% confidence interval [CI], 16.5-18.6) visits per 10,000 CKD patients per month, corresponding to a relative increase from baseline of 68.4% (95% CI, 65.7%-71.2%). There was no association between estimated GFR reporting and rate of first nephrologist visit among patients without CKD. Among patients with an estimated GFR of less than 30 mL/min/1.73 m(2), the rate of first nephrologist visits increased by 134.4 (95% CI, 60.0-208.7) visits per 10,000 patients per month. This increase was predominantly seen in women, patients aged 46 to 65 years as well as those aged 86 years or older, and those with hypertension, diabetes, and comorbidity. Reporting of estimated GFR was not associated with increased rates of internal medicine or general practitioner visits or increased use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers among patients with CKD and proteinuria or the subgroup limited to patients with diabetes. CONCLUSIONS: Reporting of estimated GFR was associated with an increase in first nephrologist visits, particularly among patients with more severe kidney dysfunction, women, middle-aged and very elderly patients, and those with comorbidities. Any effect on outcomes remains to be shown.

Overview of the Alberta Kidney Disease Network.

BACKGROUND: The Alberta Kidney Disease Network is a collaborative nephrology research organization based on a central repository of laboratory and administrative data from the Canadian province of Alberta. DESCRIPTION: The laboratory data within the Alberta Kidney Disease Network can be used to define patient populations, such as individuals with chronic kidney disease (using serum creatinine measurements to estimate kidney function) or anemia (using hemoglobin measurements). The administrative data within the Alberta Kidney Disease Network can also be used to define cohorts with common medical conditions such as hypertension and diabetes. Linkage of data sources permits assessment of socio-demographic information, clinical variables including comorbidity, as well as ascertainment of relevant outcomes such as health service encounters and events, the occurrence of new specified clinical outcomes and mortality. CONCLUSION: The unique ability to combine laboratory and administrative data for a large geographically defined population provides a rich data source not only for research purposes but for policy development and to guide the delivery of health care. This research model based on computerized laboratory data could serve as a prototype for the study of other chronic conditions.

A Practical Approach for the Verification and Determination of Site- and Trimester-Specific Reference Intervals for Thyroid Function Tests in Pregnancy.

BACKGROUND: Population-, assay-, and trimester-specific reference intervals for thyroid function tests are necessary to assess thyroid status accurately and manage thyroid disease throughout pregnancy. This study's objective was to verify if the manufacturer's recommended trimester-specific reference intervals for thyroid tests and the American Thyroid Association's recommended total thyroxine (TT4) pregnancy reference intervals were verifiable and appropriate for use in the authors' multicultural population. METHODS: Blood samples were obtained from the following sources: stored frozen surplus blood from women undergoing routine aneuploidy screening (first- and second-trimester samples, n = 274), women participating in an observational cohort study (second- and third-trimester samples, n = 135), and blood collected from women presenting for assessment to the labor and delivery ward (third-trimester samples, n = 35). Exclusions included thyroid medication or disease and positive thyroid peroxidase antibodies (anti-TPO). Samples were analyzed for thyrotropin (TSH), free T4 (fT4), free triiodothyronine (fT3), TT4, and anti-TPO using the Roche Cobas 8000 Modular e602 electrochemiluminescence immunoassay. RESULTS: Nine percent of the aneuploidy screening samples were excluded prior to thyroid testing due to maternal use of thyroid medication. Six percent of analyzed samples were excluded: 5.9% with positive anti-TPO and one with a TSH >10 mIU/L. The manufacturer's recommended trimester-specific reference intervals for TSH were not verified by described standardized methods. Therefore, 95th percentile reference intervals were determined using a minimum number of samples. Reference intervals for TSH and fT4 were as follows: 9-12 weeks, 0.18-2.99 mIU/L and 11-19.2 pmol/L; second trimester, 0.11-3.98 mIU/L and 10.5-18.2 pmol/L; and third trimester, 0.48-4.71 mIU/L and 9.0-16.1 pmol/L, respectively. The TT4 reference interval after 19 weeks' gestation was 77-186 nmol/L. CONCLUSIONS: This study provides a simple approach to verify or establish trimester-specific thyroid function reference intervals in local populations. The TT4 reference interval was lower than the interval proposed by the American Thyroid Association, suggesting the need for further study of TT4 in pregnancy and reliance on locally established fT4 reference intervals after 19 weeks, especially when there are no equivalent reference intervals for TT4.

Influence of Gastric Emptying and Gut Transit Testing on Clinical Management Decisions in Suspected Gastroparesis.

INTRODUCTION: Gastric emptying scintigraphy (GES) or wireless motility capsules (WMCs) can evaluate upper gastrointestinal symptoms in suspected gastroparesis; WMC tests can also investigate lower gut symptoms. We aimed to determine whether these tests impact treatment plans and needs for additional diagnostic evaluation. METHODS: In a prospective, multicenter study, 150 patients with gastroparesis symptoms simultaneously underwent GES and WMC testing. Based on these results, investigators devised management plans to recommend changes in medications, diet, and surgical therapies and order additional diagnostic tests. RESULTS: Treatment changes were recommended more often based on the WMC vs GES results (68% vs 48%) (P < 0.0001). Ordering of additional test(s) was eliminated more often with WMC vs GES (71% vs 31%) (P < 0.0001). Prokinetics (P = 0.0007) and laxatives (P < 0.0001) were recommended more often based on the WMC vs GES results. Recommendations for prokinetics and gastroparesis diets were higher and neuromodulators lower in subjects with delayed emptying on both tests (all P ≤ 0.0006). Laxatives and additional motility tests were ordered more frequently for delayed compared with normal WMC colonic transit (P ≤ 0.02). Multiple motility tests were ordered more often on the basis of GES vs WMC findings (P ≤ 0.004). Antidumping diets and transit slowing medications were more commonly recommended for rapid WMC gastric emptying (P ≤ 0.03). DISCUSSION: WMC transit results promote medication changes and eliminate additional diagnostic testing more often than GES because of greater detection of delayed gastric emptying and profiling the entire gastrointestinal tract in patients with gastroparesis symptoms. TRANSLATIONAL IMPACT: Gastric scintigraphy and WMCs have differential impact on management decisions in suspected gastroparesis.

Extubation force: tape versus endotracheal tube holders.

STUDY OBJECTIVE: Tape is the standard method for securing endotracheal tubes to prevent extubation. This study examines the force required to extubate endotracheal tubes from cadavers with either tape or one of 4 commercially available endotracheal tube holders. METHODS: Newly deceased, unembalmed cadavers were intubated with standard tracheal intubation techniques. The endotracheal tube was secured with either tape or one of 4 commercially available endotracheal tube holders. The endotracheal tube was then connected to a force-measuring device and pulled until the cuff was removed from the trachea. The largest force recorded on the device was then marked as the "extubation force" for that trial. RESULTS: When tape was used to secure the endotracheal tube, it required a significantly larger force to extubate than 3 of 4 off-the-shelf endotracheal tube holders. Only the Thomas Tube Holder secured the endotracheal tube better than tape. CONCLUSION: Although the Thomas Tube Holder had the greatest holding force in this study, tape was shown to be the least expensive and outperformed 3 other commercially available devices used to secure endotracheal tubes.

Epitope-specific immunotherapy targeting CD4-positive T cells in coeliac disease: two randomised, double-blind, placebo-controlled phase 1 studies.

BACKGROUND: A gluten-free diet is the only means to manage coeliac disease, a permanent immune intolerance to gluten. We developed a therapeutic vaccine, Nexvax2, designed to treat coeliac disease. Nexvax2 is an adjuvant-free mix of three peptides that include immunodominant epitopes for gluten-specific CD4-positive T cells. The vaccine is intended to engage and render gluten-specific CD4-positive T cells unresponsive to further antigenic stimulation. We assessed the safety and pharmacodynamics of the vaccine in patients with coeliac disease on a gluten-free diet. METHODS: We did two randomised, double-blind, placebo-controlled, phase 1 studies at 12 community sites in Australia, New Zealand, and the USA, in HLA-DQ2·5-positive patients aged 18-70 years who had coeliac disease and were on a gluten-free diet. In the screening period for ascending dose cohorts, participants were randomly assigned (1:1) by central randomisation with a simple block method to a double-blind crossover, placebo-controlled oral gluten challenge. Participants with a negative interferon γ release assay to Nexvax2 peptides after the screening oral gluten challenge were discontinued before dosing. For the biopsy cohorts, the screening period included an endoscopy, and participants with duodenal histology who had a Marsh score of greater than 1 were discontinued before dosing. Participants were subsequently randomly assigned to either Nexvax2 or placebo in ascending dose cohorts (2:1) and in biopsy cohorts (1:1) by central randomisation with a simple block method. In the three-dose study, participants received either Nexvax2 60 µg, 90 µg, or 150 µg weekly, or placebo over 15 days; in a fourth biopsy cohort, patients received either Nexvax2 at the maximum tolerated dose (MTD) or placebo. In the 16-dose study, participants received Nexvax2 150 µg or 300 µg or placebo twice weekly over 53 days; in a third biopsy cohort, patients also received either Nexvax2 at the MTD or placebo. In the 4-week post-treatment period, ascending dose cohorts underwent a further double-blind crossover, placebo-controlled oral gluten challenge, which had a fixed sequence, and biopsy cohorts had a gastroscopy with duodenal biopsies and quantitative histology within 2 weeks without oral gluten challenge. Participants, investigators, and study staff were masked to the treatment assignment, except for the study pharmacist. The primary endpoint was the number and percentage of adverse events in the treatment period in an intention-to-treat analysis. Both trials were completed and closed before data analysis. Trials were registered with the Australian New Zealand Clinical Trials Registry, numbers ACTRN12612000355875 and ACTRN12613001331729. FINDINGS: Participants were enrolled from Nov 28, 2012, to Aug 14, 2014, in the three-dose study, and from Aug 3, 2012, to Sept 10, 2013, in the 16-dose study. Overall, 62 (57%) of 108 participants were randomly assigned after oral gluten challenge and 20 (71%) of 28 participants were randomly assigned after endoscopy. In the three-dose study, nine participants were randomly allocated to Nexvax2 60 µg and three to placebo (first cohort), nine were allocated to Nexvax2 90 µg and four to placebo (second cohort), eight were allocated to Nexvax2 150 µg and four to placebo (third cohort), and three were allocated to Nexvax2 150 µg and three to placebo (biopsy cohort). In the 16-dose study, eight participants were randomly allocated to Nexvax2 150 µg and four to placebo (first cohort), ten were allocated to Nexvax2 300 µg and three to placebo (second cohort), and seven were allocated to Nexvax2 150 µg and seven to placebo (biopsy cohort). The MTD for Nexvax2 was 150 µg because of transient, acute gastrointestinal adverse events with onset 2-5 h after initial doses of the vaccine, similar to those caused by gluten ingestion. In the ascending dose cohorts in the three-dose study, six (55%) of 11 placebo recipients, five (56%) of nine who received Nexvax2 60 µg, seven (78%) of nine who received Nexvax2 90 µg, and five (63%) of eight who received Nexvax2 150 µg had at least one treatment-emergent adverse event, as did all three (100%) placebo recipients and one (33%) of three Nexvax2 150 µg recipients in the biopsy cohort. In the ascending dose cohorts of the 16-dose study, five (71%) of seven placebo-treated participants, six (75%) of eight who received Nexvax2 150 µg, and all ten (100%) who received Nexvax2 300 µg had at least one treatment-emergent adverse event, as did six (86%) of seven placebo recipients and five (71%) of seven Nexvax2 150 µg recipients in the biopsy cohort. Vomiting, nausea, and headache were the only treatment-emergent adverse events that occurred in at least 5% of participants in either study. Among participants given the MTD, eight gastrointestinal treatment-emergent adverse events occurred in four (50%) of eight participants in the third cohort and none (0%) of three participants in the biopsy cohort in the three-dose study, and five events occurred in five (63%) of eight participants in the first cohort and three events in two (29%) of seven participants in the biopsy cohort of the 16-dose study. Median villous height to crypt depth ratio in distal duodenal biopsies was not significantly different between those who received the vaccine at the MTD on either schedule and those who received placebo. Of the participants who completed the post-treatment oral gluten challenge per protocol, interferon γ release assay to Nexvax2 peptides was negative (responders to treatment) in two (22%) of nine placebo-treated participants in the three-dose study versus two (33%) of six who received Nexvax2 60 µg, five (63%) of eight who received Nexvax2 90 µg, and six (100%) of six who received Nexvax2 150 µg (p=0·007); in the 16-dose study, none (0%) of five placebo-treated participants had a negative assay versus six (75%) of eight who received Nexvax2 150 µg (p=0·021). INTERPRETATION: The MTD of Nexvax2 was 150 µg for twice weekly intradermal administration over 8 weeks, which modified immune responsiveness to Nexvax2 peptides without deterioration in duodenal histology. The gastrointestinal symptoms that followed the first intradermal administration of the vaccine resembled those associated with oral gluten challenge. These findings support continued clinical development of this potential therapeutic vaccine for coeliac disease. FUNDING: ImmusanT.

Erroneous HbA1c results in a patient with elevated HbC and HbF.

BACKGROUND: HbA1c is used in the diagnosis and monitoring of diabetes mellitus (DM). Interference from hemoglobin variants is a well-described phenomenon, particularly with HPLC-based methods. While immunoassays may generate more reliable HbA1c results in the presence of some variants, these methods are susceptible to negative interference from high concentrations of HbF. We report a case where an accurate HbA1c result could not be obtained by any available method due to the presence of a compound hemoglobinopathy. METHODS: HbA1c was measured by HPLC, immunoassay, and capillary electrophoresis. Hemoglobinopathy investigation consisted of a CBC, hemoglobin fractionation by HPLC and electrophoresis, and molecular analysis. RESULTS: HbA1c analysis by HPLC and capillary electrophoresis gave no result. Analysis by immunoassay yielded HbA1c results of 5.9% (Siemens DCA 2000+) and 5.1% (Roche Integra), which were inconsistent with other markers of glycemic control. Hemoglobinopathy investigation showed HbC with the hereditary persistence of fetal hemoglobin-2 Ghana deletion. CONCLUSION: Reliable HbA1c results may be unobtainable in the presence of some hemoglobinopathies. HPLC and capillary electrophoresis alerted the laboratory to the presence of an unusual hemoglobinopathy. Immunoassays generated falsely low results without warning, which could lead to missed diagnoses and under treatment of patients with DM.

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.

Identification of Hb Wayne and its effects on HbA1c measurement by 5 methods.

BACKGROUND: The World Health Organization and the American and Canadian Diabetes Associations approved HbA1c >6.5% as diagnostic for type 2 diabetes mellitus (T2DM). Hb variants and/or their chemically modified species can interfere with HbA1c measurements. We recently described a patient with Hb Wayne trait who was misdiagnosed with T2DM based on falsely elevated HbA1c. Hb Wayne is a clinically silent variant that exists as two isoforms: Hb Wayne I (Asn 139) and Hb Wayne II (Asp 139). METHODS: Hemoglobinopathy investigation was performed by HPLC (Bio-Rad VARIANT-II), alkaline and acid electrophoresis (Sebia Hydrasis2), capillary zone electrophoresis (Sebia CAPILLARYS2™) and DNA sequencing. HbA1c was measured by five methods. RESULTS: Hb Wayne eluted as two small fractions with retention times of 1.0 and 1.46min on the HPLC (Bio-Rad VARIANT-II). Alkaline gel and capillary electrophoresis showed two small bands migrating faster than HbA. Hb Wayne generated spuriously high results on the Bio-Rad VARIANT-II Turbo 2.0, no results on the Tosoh G8, and did not interfere with either the Sebia CAPILLARYS2™ or immunoassays from Roche (tinaquant) and Siemens (Bayer DCA2000+). Based on the Hb Wayne HPLC profile of 3 patients, an algorithm was developed to facilitate its detection, which identified 9 additional patients with Hb Wayne trait. CONCLUSIONS: We characterize Hb Wayne by chromatographic and electrophoretic techniques and show the effect of Hb Wayne on five common HbA1c methodologies. We developed a quality assurance tool to assist in detecting Hb Wayne trait during HbA1c analysis on the Bio-Rad VARIANT-II™ Turbo 2.0.

Effect of hemolysis on cardiac troponin T determination by the Elecsys 2010 immunoanalyzer.

OBJECTIVE: To evaluate the effect of hemolysis on the measurement of cardiac troponin T (cTnT) using the Elecsys 2010 immunoanalyzer. METHODS: cTnT concentrations were measured using the Elecsys 2010. Interference studies were conducted by mixing serum of known cTnT concentration with either hemolysates or serum to which purified hemoglobin (Hgb) had been added. Hemolysates were prepared by mechanical disruption. PROBIT analysis was conducted to determine the probability of a cTnT result of >0.1 microg/l being decreased to <0.1 microg/l due to hemoglobin interference. RESULTS: Purified hemoglobin as well as serum-hemolysates mediated a concentration-dependent inhibition of cTnT determination with the Elecsys 2010. With every 1 g/l increase in hemoglobin, the probability of cTnT >0.1 is decreased by 2.5%. CONCLUSIONS: A concentration-dependent negative bias in the measurement of cTnT is associated with increasing hemoglobin concentrations in serum.