Background: Microcystins are an emergent public health problem. These toxins are secondary metabolites of harmful cyanobacterial blooms, with blooms becoming more prevalent with eutrophication of water. Exposure to microcystins can result in sickness, liver damage, and even death. Over 300 microcystins have been identified to date, with differences in toxicity based on the specific amino acid composition. Because of this diversity in microcystins, as well as the likelihood of detecting as yet undiscovered microcystins, it is vital to establish a methodological workflow to identify any microcystin in a complex sample, regardless of the availability of a reference standard. Additionally, ascribing varying levels of confidence to these identifications is critical to effectively communicate discoveries. Methods: A liquid-chromatography–high-resolution mass spectrometry method was utilized to identify microcystins present in cyanobacterial extracts from a strain of Microcystis aeruginosa and an Aphanizomenon sp. First, microcystin congeners with available standards were identified in the cyanobacterial extract. These known-unknown microcystins were considered to have the highest confidence identifications due to availability of accurate masses, retention times, and library spectra for comparison. Utilizing the spectra of these microcystins, relatively high-abundance diagnostic product-ions were identified and employed to screen the data for additional candidate microcystins. Microcystins without a standard that had an exact mass matching a microcystin published in CyanoMetDB were considered semi-known-unknown microcystins. The remaining microcystins were considered unknown-unknown microcystins. The identities of the microcystins determined herein were additionally supported by product-ion analysis, thiol reactivity, esterification reactions, neutral loss analysis, and literature contextualization. Results: In total, utilizing the systematic workflow presented herein, 23 microcystins were identified in the M. aeruginosa culture, including two not published previously: [D-Asp3]MC-LCit and the incompletely identified MC-L(C7H11NO3). © 2024

Harmful cyanobacterial blooms are becoming more common and persistent around the world. When in bloom, various cyanobacterial strains can produce anatoxins in high concentrations, which, unlike other cyanobacterial toxins, may be present in clear water. Potential human and animal exposures to anatoxins occur mainly through unintentional ingestion of contaminated algal mats and water. To address this public health threat, we developed and validated an LC-MS/MS method to detect anatoxins in human urine to confirm exposures. Pooled urine was fortified with anatoxin-a and dihydroanatoxin at concentrations from 10.0 to 500 ng/mL to create calibrators and quality control samples. Samples were diluted with isotopically labeled anatoxin and solvent prior to LC-MS/MS analysis. This method can accurately quantitate anatoxin-a with inter- and intraday accuracies ranging from 98.5 to 103% and relative standard deviations < 15%, which is within analytical guidelines for mass spectrometry methods. Additionally, this method qualitatively detects a common degradation product of anatoxin, dihydroanatoxin, above 10 ng/mL. We also evaluated a commercial anatoxin-a ELISA kit for potential diagnostic use; however, numerous false positives were detected from unexposed individual human urine samples. In conclusion, we have developed a method to detect anatoxins precisely and accurately in urine samples, addressing a public health area of concern, which can be applied to future exposure events.

BACKGROUND: Simultaneous urine testing for albumin (UAlb) and serum creatinine (SCr), that is, 'dual testing,' is an accepted quality measure in the management of diabetes. As chronic kidney disease (CKD) is defined by both UAlb and SCr testing, this approach could be more widely adopted in kidney care. OBJECTIVE: We assessed time trends and facility-level variation in the performance of outpatient dual testing in the integrated Veterans Health Administration (VHA) system. DESIGN, SUBJECTS AND MAIN MEASURES: This retrospective cohort study included patients with any inpatient or outpatient visit to the VHA system during the period 2009-2018. Dual testing was defined as UAlb and SCr testing in the outpatient setting within a calendar year. We assessed time trends in dual testing by demographics, comorbidities, high-risk (eg, diabetes) specialty care and facilities. A generalised linear mixed-effects model was applied to explore individual and facility-level predictors of receiving dual testing. KEY RESULTS: We analysed data from approximately 6.9 million veterans per year. Dual testing increased, on average, from 17.4% to 21.2%, but varied substantially among VHA centres (0.3%-43.7% in 2018). Dual testing was strongly associated with diabetes (OR 10.4, 95% CI 10.3 to 10.5, p<0.0001) and not associated with VHA centre complexity level. However, among patients with high-risk conditions including diabetes, <50% received dual testing in any given year. As compared with white veterans, black veterans were less likely to be tested after adjusting for other individual and facility characteristics (OR 0.93, 95% CI 0.92 to 0.93, p<0.0001). CONCLUSIONS: Dual testing for CKD in high-risk specialties is increasing but remains low. This appears primarily due to low rates of testing for albuminuria. Promoting dual testing in high-risk patients will help to improve disease management and patient outcomes.

BACKGROUND: Inflammation may affect long-term kidney function. Diet may play a role in chronic inflammation. We hypothesized that proinflammatory diets increase the risk of progression to kidney failure with replacement therapy (KFRT), and systemic inflammation is a mediator of the effect of diet on progression to KFRT. METHODS: In the 1988-1994 National Health and Nutrition Examination Survey linked to the national ESKD registry, in adults with CKD (eGFR 15-59 ml/min per 1.73 m(2)), aged ≥20 years, we calculated the Adapted Dietary Inflammatory Index (ADII) at baseline from a 24-hour dietary recall and an inflammation score (IS) using average of z scores of four inflammation biomarkers. We explored the association of the ADII and IS with risk of incident KFRT using Cox proportional model, adjusting for sociodemographics, physical activity, Framingham risk score, eGFR, and urinary ACR. We evaluated whether, and to what extent, IS mediated the effect of the ADII on KFRT incidence, using causal mediation analysis. RESULTS: Of 1084 adults with CKD, 109 (10%) developed KFRT. The ADII was associated with increased risk of KFRT (relative hazard [RH] per SD increase (2.56): 1.4 [1.04-1.78]). IS was also associated with KFRT (RH: 1.12; 95% CI, 1.02 to 1.25). Approximately 36% of the association between the ADII and KFRT was explained by IS. CONCLUSIONS: Among adults with CKD, a proinflammatory diet was associated with risk of KFRT, and that association was partially explained by an increase in inflammatory markers. Dietary interventions that reduce inflammation may offer an approach for preventing KFRT.

In October 2022, the Southern Nevada Health District (SNHD) was notified of a higher-than-expected number of pediatric patients hospitalized with intracranial abscesses; similar concerns were previously reported nationally (1,2). This rare infection is associated with significant morbidity (3,4). When SNHD received the report in October 2022, 14 cases had been diagnosed in the largest pediatric hospital in southern Nevada. SNHD investigated the reported increase to confirm that a cluster had been detected, identify common risk factors for infection, report findings to the community, and recommend measures to prevent future cases.

BACKGROUND: Shigella species, which cause acute diarrheal disease, are transmitted via fecal-oral and sexual contact. To better understand the overlapping populations affected by Shigella infections and sexually transmitted infections (STIs) in the United States, we examined the occurrence of reported STIs within 24 months among shigellosis case-patients. METHODS: Culture-confirmed Shigella cases diagnosed during 2007-2016 among residents of six U.S. jurisdictions were matched to reports of STIs (chlamydia, gonorrhea, and all stages of syphilis) diagnosed 12 months before or after the shigellosis case. We examined epidemiologic characteristics and reported temporal trends of Shigella cases by sex and species. RESULTS: During 2007-2016, 10,430 shigellosis cases were reported. The annual number of reported shigellosis cases across jurisdictions increased 70%, from 821 cases in 2007 to 1,398 cases in 2016; males saw a larger increase compared to females. Twenty percent of male shigellosis case-patients had an STI reported in the reference period, versus 4% of female case-patients. The percentage of male shigellosis case-patients with an STI increased from 11% (2007) to 28% (2016); the overall percentage among females remained low. CONCLUSIONS: We highlight the substantial proportion of males with shigellosis who were diagnosed with STIs within 24 months and the benefit of matching data across programs. STI screening may be warranted for male shigellosis case-patients.

To combat the ongoing opioid epidemic, our laboratory has developed and evaluated an approach to detect fentanyl analogs in urine and plasma by screening LC-QTOF MS/MS spectra for ions that are diagnostic of the core fentanyl structure. MS/MS data from a training set of 142 fentanyl analogs were used to select the four product ions and six neutral losses that together provided the most complete coverage (97.2%) of the training set compounds. Furthermore, using the diagnostic ion screen against a set of 49 fentanyl analogs not in the training set resulted in 95.9% coverage of those compounds. With this approach, lower reportable limits for fentanyl and a subset of fentanyl-related compounds range from 0.25 to 2.5 ng/mL in urine and 0.5 to 5.0 ng/mL in plasma. This innovative processing method was applied to evaluate simulated exposure samples of remifentanil and carfentanil in water and their metabolites remifentanil acid and norcarfentanil in urine. This flexible approach enables a way to detect emerging fentanyl analogs in clinical samples.

IMPORTANCE: Significant racial and ethnic disparities in chronic kidney disease (CKD) progression and outcomes are well documented, as is low use of guideline-recommended CKD care. OBJECTIVE: To examine guideline-recommended CKD care delivery by race and ethnicity in a large, diverse population. DESIGN, SETTING, AND PARTICIPANTS: In this serial cross-sectional study, adult patients with CKD that did not require dialysis, defined as a persistent estimated glomerular filtration rate less than 60 mL/min/1.73 m2 or a urine albumin-creatinine ratio of 30 mg/g or higher for at least 90 days, were identified in 2-year cross-sections from January 1, 2012, to December 31, 2019. Data from the OptumLabs Data Warehouse, a national data set of administrative and electronic health record data for commercially insured and Medicare Advantage patients, were used. EXPOSURES: The independent variables were race and ethnicity, as reported in linked electronic health records. MAIN OUTCOMES AND MEASURES: On the basis of guideline-recommended CKD care, the study examined care delivery process measures (angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker prescription for albuminuria, statin prescription, albuminuria testing, nephrology care for CKD stage 4 or higher, and avoidance of chronic nonsteroidal anti-inflammatory drug prescription) and care delivery outcome measures (blood pressure and diabetes control). RESULTS: A total of 452 238 patients met the inclusion criteria (mean [SD] age, 74.0 [10.2] years; 262 089 [58.0%] female; a total of 7573 [1.7%] Asian, 49 970 [11.0%] Black, 15 540 [3.4%] Hispanic, and 379 155 [83.8%] White). Performance on process measures was higher among Asian, Black, and Hispanic patients compared with White patients for angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker use (79.8% for Asian patients, 76.7% for Black patients, and 79.9% for Hispanic patients compared with 72.3% for White patients in 2018-2019), statin use (72.6% for Asian patients, 69.1% for Black patients, and 74.1% for Hispanic patients compared with 61.5% for White patients), nephrology care (64.8% for Asian patients, 72.9% for Black patients, and 69.4% for Hispanic patients compared with 58.3% for White patients), and albuminuria testing (53.9% for Asian patients, 41.0% for Black patients, and 52.6% for Hispanic patients compared with 30.7% for White patients). Achievement of blood pressure control to less than 140/90 mm Hg was similar or lower among Asian (71.8%), Black (63.3%), and Hispanic (69.8%) patients compared with White patients (72.9%). Achievement of diabetes control with hemoglobin A1c less than 7.0% was 50.1% in Asian patients, 49.3% in Black patients, and 46.0% in Hispanic patients compared with 50.3% for White patients. CONCLUSIONS AND RELEVANCE: Higher performance on CKD care process measures among Asian, Black, and Hispanic patients suggests that differences in medication prescription and diagnostic testing are unlikely to fully explain known disparities in CKD progression and kidney failure. Improving care delivery processes alone may be inadequate for reducing these disparities.

BACKGROUND: To better understand the relation between sleep problems and CKD, we examined temporal trends in the prevalence of self-reported sleep problems in adults in the United States and their associations with CKD and all-cause mortality. METHODS: Using data from 27,365 adult participants in five biannual National Health and Examination Surveys (2005-2006 through 2013-2014), we studied five self-reported sleep problems-trouble sleeping, sleep disorder, nocturia (urinating ≥2 times/night), inadequate sleep (<7 hours/night), and excessive sleep (>9 hours/night)-plus a composite index. We conducted three types of analysis: temporal trends in the prevalence of each sleep measure by CKD status, using model-based standardization; cross-sectional analysis of associations between four CKD measures and each sleep measure, using logistic regression; and survival analysis of the association between each sleep measure and mortality, using Cox regression. RESULTS: The prevalence of trouble sleeping and sleep disorder increased over the five surveys by 4% and 3%, respectively, whereas the other sleep problems remained relatively stable. All sleep problems, except inadequate sleep, were more common during the study period among adults with CKD than without CKD (40% versus 21% for nocturia; 5% versus 2% for excessive sleep; 30% versus 25% for trouble sleeping; 12% versus 8% for sleep disorder). Both eGFR <30 ml/min per 1.73 m(2) and albuminuria were positively associated with nocturia and excessive sleep. Excessive sleep and nocturia were also associated with higher mortality (adjusted hazard ratio for >9 versus 7-9 hours/night=1.7; 95% CI, 1.3 to 2.1; and for nocturia=1.2; 95% CI, 1.1 to 1.4). CONCLUSIONS: The high prevalence of sleep problems among persons with CKD and their associations with mortality suggest their potential importance to clinical practice. Future work could examine the health effects of identifying and treating sleep problems in patients with CKD.

Since 2003, US hypertension guidelines have recommended ACE (angiotensin-converting enzyme) inhibitors or ARBs (angiotensin receptor blockers) as first-line antihypertensive therapy in the presence of albuminuria (urine albumin/creatinine ratio ≥300 mg/g). To examine national trends in guideline-concordant ACE inhibitor/ARB utilization, we studied adults participating in the National Health and Nutrition Examination Surveys 2001 to 2018 with hypertension (defined by self-report of high blood pressure, systolic blood pressure ≥140 mm Hg or diastolic ≥90 mm Hg, or use of antihypertensive medications). Among 20 538 included adults, the prevalence of albuminuria ≥300 mg/g was 2.8% in 2001 to 2006, 2.8% in 2007 to 2012, and 3.2% in 2013 to 2018. Among those with albuminuria ≥300 mg/g, no consistent trends were observed for the proportion receiving ACE inhibitor/ARB treatment from 2001 to 2018 among persons with diabetes, without diabetes, or overall. In 2013 to 2018, ACE inhibitor/ARB usage in the setting of albuminuria ≥300 mg/g was 55.3% (95% CI, 46.8%-63.6%) among adults with diabetes and 33.4% (95% CI, 23.1%-45.5%) among those without diabetes. Based on US population counts, these estimates represent 1.6 million adults with albuminuria ≥300 mg/g currently not receiving ACE inhibitor/ARB therapy, nearly half of whom do not have diabetes. ACE inhibitor/ARB underutilization represents a significant gap in preventive care delivery for adults with hypertension and albuminuria that has not substantially changed over time.

Human exposures to fentanyl analogs, which significantly contribute to the ongoing U.S. opioid overdose epidemic, can be confirmed through the analysis of clinical samples. Our laboratory has developed and evaluated a qualitative approach coupling liquid chromatography and quadrupole time-of-flight mass spectrometry (LC-QTOF) to address novel fentanyl analogs and related compounds using untargeted, data-dependent acquisition. Compound identification was accomplished by searching against a locally-established mass spectral library of 174 fentanyl analogs and metabolites. Currently, our library can identify 150 fentanyl-related compounds from the Fentanyl Analog Screening (FAS) Kit), plus an additional 25 fentanyl-related compounds from individual purchases. Plasma and urine samples fortified with fentanyl-related compounds were assessed to confirm the capabilities and intended use of this LC-QTOF method. For fentanyl, 8 fentanyl-related compounds and naloxone, lower reportable limits (LRL100), defined as the lowest concentration with 100 % true positive rate (n = 12) within clinical samples, were evaluated and range from 0.5 ng/mL to 5.0 ng/mL for urine and 0.25 ng/mL to 2.5 ng/mL in plasma. The application of this high resolution mass spectrometry (HRMS) method enables the real-time detection of known and emerging synthetic opioids present in clinical samples.

BACKGROUND: Acid retention associated with reduced GFR exacerbates nephropathy progression in partial nephrectomy models of CKD and might be reflected in CKD patients with reduced eGFR by increased anion gap (AG). METHODS: We explored the presence of AG and its association with CKD in 14,924 adults, aged >/=20 years and eGFR>/=15ml/min/1.73m(2), enrolled in the National Health and Nutrition Examination Survey III, 1988-1994 using multivariable regression analysis. The model was adjusted for socio-demographic characteristics, diabetes, and hypertension. We further examined the association between AG and incident end-stage renal disease using frailty models, adjusting for demographics, clinical factors, BMI, serum albumin, bicarbonate, eGFR, and urinary albumin-to-creatinine ratio, by following 558 adults with moderate CKD for 12 years via the United States Renal Data System. Laboratory measures determined AG using the traditional, albumin-corrected, and full AG definitions. RESULTS: Individuals with moderate CKD (eGFR 30-59 ml/min/1.73 m(2)) had a greater AG than those with eGFR>/=60 ml/min in multivariable regression analysis with adjustment for covariates. We found a graded relationship between the adjusted mean for all three definitions of AG and eGFR categories (p trend<0.0001). During follow-up, 9.2% of adults with moderate CKD developed ESRD. Those with AG in the highest tertile had a higher risk of ESRD, after adjusting for covariates in a frailty model (Relative risk [95% CI] for traditional AG:1.8[1.2-2.3]), compared to those in the middle tertile. CONCLUSIONS: The data suggest that high AG, even after adjusting for serum bicarbonate, is a contributing acid-base mechanism to CKD progression in moderate CKD.

The Dietary Approaches to Stop Hypertension (DASH) diet lowers blood pressure, an important risk factor for chronic kidney disease (CKD) and end-stage renal disease (ESRD). However, it is unclear whether adherence to a DASH diet confers protection against future ESRD, especially among those with pre-existing CKD and hypertension. We examined whether a DASH diet is associated with lower risk of ESRD among 1,110 adults aged >/= 20 years with hypertension and CKD (estimated glomerular filtration rate, eGFR 30-59 ml/min/1.73 m(2)) enrolled in the National Health and Nutrition Examination Survey (1988-1994). Baseline DASH diet accordance score was assessed using a 24-hour dietary recall questionnaire. ESRD was ascertained by linkage to the U.S. Renal Data System registry. We used the Fine-Gray competing risks method to estimate the relative hazard (RH) for ESRD after adjusting for sociodemographics, clinical and nutritional factors, eGFR, and albuminuria. Over a median follow-up of 7.8 years, 18.4% of subjects developed ESRD. Compared to the highest quintile of DASH diet accordance, there was a greater risk of ESRD among subjects in quintiles 1 (RH=1.7; 95% CI 1.1-2.7) and 2 (RH 2.2; 95% CI 1.1-4.1). Significant interactions were observed with diabetes status and race/ethnicity, with the strongest association between DASH diet adherence and ESRD risk observed in individuals with diabetes and in non-Hispanic blacks. Low accordance to a DASH diet is associated with greater risk of ESRD in adults with moderate CKD and hypertension, particularly in non-Hispanic blacks and persons with diabetes.

BACKGROUND: Considerable geographic variation exists in the prevalence of chronic kidney disease across the United States. While some of this variability can be explained by differences in patient-level risk factors, substantial variability still exists. We hypothesize this may be due to understudied environmental exposures such as air pollution. METHODS: Using data on 1.1 million persons from the 2010 5% Medicare sample and Environmental Protection Agency air-quality measures, we examined the association between county-level particulate matter </=2.5 mum (PM2.5) and the prevalence of diagnosed CKD, based on claims. Modified Poisson regression was used to estimate associations (prevalence ratios [PR]) between county PM2.5 concentration and individual-level diagnosis of CKD, adjusting for age, sex, race/ethnicity, hypertension, diabetes, and urban/rural status. RESULTS: Prevalence of diagnosed CKD ranged from 0% to 60% by county (median = 16%). As a continuous variable, PM2.5 concentration shows adjusted PR of diagnosed CKD = 1.03 (95% CI: 1.02-1.05; p<0.001) for an increase of 4 mug/m3 in PM2.5. Investigation by quartiles shows an elevated prevalence of diagnosed CKD for mean PM2.5 levels >/=14 mug/m3 (highest quartile: PR = 1.05, 95% CI: 1.03-1.07), which is consistent with current ambient air quality standard of 12 mug/m3, but much lower than the level typically considered healthy for sensitive groups (~40 mug/m3). CONCLUSION: A positive association was observed between county-level PM2.5 concentration and diagnosed CKD. The reliance on CKD diagnostic codes likely identified associations with the most severe CKD cases. These results can be strengthened by exploring laboratory-based diagnosis of CKD, individual measures of exposure to multiple pollutants, and more control of confounding.

A case of an elderly female with suspected paralytic shellfish poisoning (PSP) is presented. The patient shared a meal of recreationally-harvested shellfish with her family and soon began to experience nausea and weakness. She was taken to the local emergency department and then transported to a larger hospital in Anchorage where she was admitted to the intensive care unit with respiratory depression and shock. Her condition improved, and she was discharged from the hospital 6 days later. No others who shared the meal reported symptoms of PSP. A clam remaining from the meal was collected and analyzed for paralytic shellfish toxins (PST) by the Alaska Department of Environmental Conservation Environmental Health Laboratory; the clam tested positive for saxitoxin (STX; 277 mug/100 g), neosaxitoxin (NEO; 309 mug/100 g), multiple gonyautoxins (GTX; 576-2490 mug/100 g), decarbamoyl congeners (7.52-11.3 mug/100 g) and C-toxins (10.8-221 mug/100 g) using high-pressure liquid chromatography with post-column oxidation (AOAC Method 2011.02). Urine from the patient was submitted to Centers for Disease Control for analysis of selected PSTs and creatinine. STX (64.0 mug/g-creatinine), NEO (60.0 mug/g-creatinine) and GTX1-4 (492-4780 mug/g-creatinine) were identified in the urine using online solid phase extraction with HPLC and tandem mass spectrometry. This was the first time GTX were identified in urine of a PSP case from Alaska, highlighting the need to include all STX congeners in testing to protect the public's health through a better understand of PST toxicity, monitoring and prevention of exposures.

AIM: An immunomagnetic capture protocol for use with LC-MS was developed for the quantitation of saxitoxin (STX) in human urine. MATERIALS & METHODS: This method uses monoclonal antibodies coupled to magnetic beads. STX was certified reference material grade from National Research Council, Canada. Analysis was carried out using LC-MS. RESULTS: With an extraction efficiency of 80%, accuracy and precision of 93.0-100.2% and 5.3-12.6%, respectively, and a dynamic range of 1.00-100 ng/ml, the method is well suited to quantify STX exposures based on previously reported cases. CONCLUSION: Compared with our previously published protocols, this method has improved selectivity, a fivefold increase in sensitivity and uses only a third of the sample volume. This method can diagnose future toxin exposures and may complement the shellfish monitoring programs worldwide.

This study was conducted among U.S. Army soldiers to evaluate the association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid (CHA) detected in test subjects (n = 87) after completion of Mask Confidence Training. CS exposures ranged 0.086 - 4.9 mg/m(3) ([Formula: see text] = 2.7 mg/m(3)). CHA levels (corrected for creatinine) at 2, 8, 24, and 30 hours post-exposure resulted in ranges of 94.6 - 1120 mug/g-cr ([Formula: see text] = 389 mug/g-cr), 15.80 - 1170 mug/g-cr ([Formula: see text] = 341 mug/g-cr), 4.00 - 53.1 mug/g-cr ([Formula: see text] = 19.3 mug/g-cr), and 1.99 - 28.4 mug/g-cr ([Formula: see text] = 10.6 mug/g-cr), respectively. Spearman's correlation revealed CHA levels strongly correlated with time sampled (r = -0.748, p < 0.05) and weakly correlated with CS concentration (r = 0.270, p < 0.05). A linear relationship was observed between CHA, CS concentration, and time of urine sample according to the following regression equation: ln(CHA, mug/g-cr) = 5.423 + 0.316 (CS conc., mg/m(3)) - 0.002 (time sampled), (R = 0.910, R(2) = 0.827, p < 0.05). This relationship suggests that CHA has the potential to be an effective retrospective indicator of CS exposure in future biomarker developments.

INTRODUCTION: This study examined state-level variation in chronic kidney disease (CKD) awareness using national estimates of disease awareness among adults in the U.S. with CKD. METHODS: Data on U.S. adults were obtained from two national, population-based surveys: (1) the Behavioral Risk Factor Surveillance System (BRFSS 2011; n=506,467), a state-level phone survey containing information on self-reported kidney disease; and (2) the National Health and Nutrition Examination Survey (NHANES 2005-2012; n=20,831), containing physical health examination, surveys containing data on self-reported kidney disease, risk factors, and laboratory values. CKD was defined as an estimated glomerular filtration rate of 15-59 mL/minute/1.73 m2 or urinary albumin-to-creatinine ratio >30 mg/g. As BRFSS does not include laboratory data, CKD status for each person was imputed (multiple) based on a logistic regression model predicting NHANES CKD status. CKD awareness in each state was estimated as the weighted proportion of BRFSS participants with imputed CKD who reported having kidney disease. RESULTS: Overall, estimated CKD awareness was 9.0% (95% CI=8.0%, 10.0%), ranging from 5.8% (95% CI=4.8%, 6.8%) in Iowa to 11.7% (95% CI=9.7%, 13.7%) in Arizona. Awareness was greater among adults with hypertension (12.0%) and diabetes (15.3%) than among adults without those conditions, and lower in Hispanics (6.0%) than in non-Hispanic whites (8.8%), non-Hispanic blacks (9.9%), and other racial/ethnic groups (12.7%). CONCLUSIONS: Among individuals with CKD, awareness of their condition was very low and varied approximately twofold among states. This is the first study to estimate awareness of kidney disease by state for the U.S. adult population.

Paralytic shellfish toxins (PSTs), including gonyautoxins and saxitoxins, are produced by multiple species of microalgae and dinoflagellates, and are bioaccumulated by shellfish and other animals. Human exposure to PSTs typically occurs through ingestion of recreationally-harvested contaminated shellfish and results in non-specific symptomology. Confirmation of exposure to PSTs has often relied on the measurement of saxitoxin, the most toxic congener; however, gonyautoxins (GTXs), the sulfated carbamate derivatives of saxitoxin, may be present in shellfish at higher concentrations. To improve identification of PST exposures, our group has developed an online solid phase extraction hydrophilic interaction liquid chromatography (HILIC) method to identify GTX1-4 in human urine with tandem mass spectrometry. The reportable range varied for each analyte, with all falling within 0.899 and 250 ng/mL in urine with precision <15% and >85% accuracy as determined for all quality control samples. This new online method quantitates GTX1-4 following exposures to PSTs, supporting the work of public health authorities.

Background: Trends in the prevalence of chronic kidney disease (CKD) are important for health care policy and planning. Objective: To update trends in CKD prevalence. Design: Repeated cross-sectional study. Setting: NHANES (National Health and Nutrition Examination Survey) for 1988 to 1994 and every 2 years from 1999 to 2012. Participants: Adults aged 20 years or older. Measurements: Chronic kidney disease (stages 3 and 4) was defined as an estimated glomerular filtration rate (eGFR) of 15 to 59 mL/min/1.73 m2, estimated with the Chronic Kidney Disease Epidemiology Collaboration equation from calibrated serum creatinine measurements. An expanded definition of CKD also included persons with an eGFR of at least 60 mL/min/1.73 m2 and a 1-time urine albumin-creatinine ratio of at least 30 mg/g. Results: The unadjusted prevalence of stage 3 and 4 CKD increased from the late 1990s to the early 2000s. Since 2003 to 2004, however, the overall prevalence has largely stabilized (for example, 6.9% prevalence in 2003 to 2004 and in 2011 to 2012). There was little difference in adjusted prevalence of stage 3 and 4 CKD overall in 2003 to 2004 versus 2011 to 2012 after age, sex, race/ethnicity, and diabetes mellitus status were controlled for (P = 0.26). Lack of increase in CKD prevalence since the early 2000s was observed in most subgroups and with an expanded definition of CKD that included persons with higher eGFRs and albuminuria. Limitation: Serum creatinine and albuminuria were measured only once in each person. Conclusion: In a reversal of prior trends, there has been no appreciable increase in the prevalence of stage 3 and 4 CKD in the U.S. population overall during the most recent decade. Primary Funding Source: American Society of Nephrology Foundation for Kidney Research Student Scholar Grant Program, Centers for Disease Control and Prevention, and National Institutes of Health.

Tetrodotoxin (TTX) is an extremely potent paralytic toxin responsible for yearly illness and death around the world. A clinical measurement is necessary to confirm exposure because symptoms of TTX intoxication cannot be distinguished from other paralytic toxins. Our group has developed an online solid phase extraction hydrophilic interaction liquid chromatography (HILIC) method for the analysis of TTX in human urine with tandem mass spectrometry. The reportable range for the method was 2.80 - 249 ng/mL in urine with precision and accuracy within 15% as determined for all quality control samples. No isotopically-labeled internal standard is available for TTX; thus a surrogate internal standard, voglibose, was investigated to compensate for matrix effects and ionization suppression. However, upon evaluation, voglibose was ineffective for this purpose. This new online method rapidly identifies TTX, facilitating the work of public health authorities and providing support to monitoring programs worldwide.

Saxitoxin (STX) and neosaxitoxin (NEO) are potent neurotoxins that cause paralytic shellfish poisoning (PSP). PSP typically occurs through the ingestion of bivalve shellfish that have consumed toxin producing dinoflagellates. Due to initial presentation of symptoms being nonspecific, a clinical measurement is needed to confirm exposure to these toxins. Our group has developed an online solid phase extraction hydrophilic interaction liquid chromatography (HILIC) method for the analysis of STX and NEO in human urine with tandem mass spectrometry. A unique feature of this online method is the incorporation of a new synthetic 15N4-STX labeled internal standard used for quantitation. Manual sample preparation time was reduced by approximately 70% for 98 urine samples as compared to a previously reported method. The lowest reportable limit for STX was improved from 5.0 ng/mL to 1.01 ng/mL and from 10.0 ng/mL to 2.62 ng/mL for NEO. Three analysts validated the method with 20 calibration curves total over 30 days with precision and accuracy within +/-15% for all QCs. This new online method rapidly identifies STX and NEO exposure with improved sensitivity, which can facilitate the work of public health authorities to confirm the cases of PSP, complementing the many shellfish monitoring programs worldwide.

Two types of automated solid phase extraction (SPE) were assessed for the determination of human exposure to fentanyls in urine. High sensitivity is required to detect these compounds following exposure because of the low dose required for therapeutic effect and the rapid clearance from the body for these compounds. To achieve this sensitivity, two acceptable methods for the detection of human exposure to seven fentanyl analogs and three metabolites were developed using either off-line 96-well plate SPE or on-line SPE. Each system offers different advantages: off-line 96-well plate SPE allows for high throughput analysis of many samples, which is needed for large sample numbers, while on-line SPE removes almost all analyst manipulation of the samples, minimizing the analyst time needed for sample preparation. Both sample preparations were coupled with reversed phase liquid chromatography and isotope dilution tandem mass spectrometry (LC-MS/MS) for analyte detection. For both methods, the resulting precision was within 15%, the accuracy within 25%, and the sensitivity was comparable with the limits of detection ranging from 0.002ng/mL to 0.041ng/mL. Additionally, matrix effects were substantially decreased from previous reports for both extraction protocols. The results of this comparison showed that both methods were acceptable for the detection of exposures to fentanyl analogs and metabolites in urine.

RATIONALE: Although use is prohibited, concerns remain for human exposure to nerve agents during decommissioning, research, and warfare. High-resolution mass spectrometry (HRMS) was compared to tandem mass spectrometry (MS/MS) analysis for the quantitation of five urinary metabolites specific to VX, Russian VX, soman, sarin and cyclosarin nerve agents. The HRMS method was further evaluated for qualitative screening of metabolites not included in the test panel. METHODS: Nerve agent metabolites were extracted from urine using solid-phase extraction, separated using hydrophilic interaction chromatography and analyzed using both tandem and high-resolution mass spectrometry. MS/MS results were obtained using selected reaction monitoring with unit resolution; HRMS results were obtained using a mass extraction window of 10 ppm at a mass resolution of 50 000. The benchtop Orbitrap HRMS instrument was operated in full scan mode, to measure the presence of unexpected nerve agent metabolites. RESULTS: The assessment of two quality control samples demonstrated high accuracy (99.5-104%) and high precision (2-9%) for both HRMS and MS/MS. Sensitivity, as described by the limit of detection, was overlapping for both detectors (0.2-0.7 ng/mL). Additionally, the HRMS method positively confirmed the presence of a nerve agent metabolite, not included in the test panel, using the accurate mass and relative retention time. CONCLUSIONS: The precision, accuracy, and sensitivity were comparable between the current MS/MS method and this newly developed HRMS analysis for five nerve agent metabolites. HRMS showed additional capabilities beyond the current method by confirming the presence of a metabolite not included in the test panel.