Interlaboratory comparison of 25-hydroxyvitamin D assays: Vitamin D Standardization Program (VDSP) Intercomparison Study 2 - Part 2 ligand binding assays - impact of 25-hydroxyvitamin D2 and 24R,25-dihydroxyvitamin D3 on assay performance.

An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of ligand binding assays (Part 2) for the determination of serum total 25-hydroxyvitamin D [25(OH)D]. Fifty single-donor samples were assigned target values for concentrations of 25-hydroxyvitamin D2 [25(OH)D2], 25-hydroxyvitamin D3 [25(OH)D3], 3-epi-25-hydroxyvitamin D3 [3-epi-25(OH)D3], and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] using isotope dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS). VDSP Intercomparison Study 2 Part 2 includes results from 17 laboratories using 32 ligand binding assays. Assay performance was evaluated using mean % bias compared to the assigned target values and using linear regression analysis of the test assay mean results and the target values. Only 50% of the ligand binding assays achieved the VDSP criterion of mean % bias ≤ |± 5%|. For the 13 unique ligand binding assays evaluated in this study, only 4 assays were consistently within ± 5% mean bias and 4 assays were consistently outside ± 5% mean bias regardless of the laboratory performing the assay. Based on multivariable regression analysis using the concentrations of individual vitamin D metabolites in the 50 single-donor samples, most assays underestimate 25(OH)D2 and several assays (Abbott, bioMérieux, DiaSorin, IDS-EIA, and IDS-iSYS) may have cross-reactivity from 24R,25(OH)2D3. The results of this interlaboratory study represent the most comprehensive comparison of 25(OH)D ligand binding assays published to date and is the only study to assess the impact of 24R,25(OH)2D3 content using results from a reference measurement procedure.

Assessment of serum total 25-hydroxyvitamin D assays for Vitamin D External Quality Assessment Scheme (DEQAS) materials distributed at ambient and frozen conditions.

The Vitamin D External Quality Assessment Scheme (DEQAS) distributes human serum samples four times per year to over 1000 participants worldwide for the determination of total serum 25-hydroxyvitamin D [25(OH)D)]. These samples are stored at -40 °C prior to distribution and the participants are instructed to store the samples frozen at -20 °C or lower after receipt; however, the samples are shipped to participants at ambient conditions (i.e., no temperature control). To address the question of whether shipment at ambient conditions is sufficient for reliable performance of various 25(OH)D assays, the equivalence of DEQAS human serum samples shipped under frozen and ambient conditions was assessed. As part of a Vitamin D Standardization Program (VDSP) commutability study, two sets of the same nine DEQAS samples were shipped to participants at ambient temperature and frozen on dry ice. Twenty-eight laboratories participated in this study and provided 34 sets of results for the measurement of 25(OH)D using 20 ligand binding assays and 14 liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Equivalence of the assay response for the frozen versus ambient DEQAS samples for each assay was evaluated using multi-level modeling, paired t-tests including a false discovery rate (FDR) approach, and ordinary least squares linear regression analysis of frozen versus ambient results. Using the paired t-test and confirmed by FDR testing, differences in the results for the ambient and frozen samples were found to be statistically significant at p < 0.05 for four assays (DiaSorin, DIAsource, Siemens, and SNIBE prototype). For all 14 LC-MS/MS assays, the differences in the results for the ambient- and frozen-shipped samples were not found to be significant at p < 0.05 indicating that these analytes were stable during shipment at ambient conditions. Even though assay results have been shown to vary considerably among different 25(OH)D assays in other studies, the results of this study also indicate that sample handling/transport conditions may influence 25(OH)D assay response for several assays.

Assessment of serum total 25-hydroxyvitamin D assay commutability of Standard Reference Materials and College of American Pathologists Accuracy-Based Vitamin D (ABVD) Scheme and Vitamin D External Quality Assessment Scheme (DEQAS) materials: Vitamin D Standardization Program (VDSP) Commutability Study 2.

An interlaboratory study was conducted through the Vitamin D Standardization Program (VDSP) to assess commutability of Standard Reference Materials® (SRMs) and proficiency testing/external quality assessment (PT/EQA) samples for determination of serum total 25-hydroxyvitamin D [25(OH)D] using ligand binding assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A set of 50 single-donor serum samples were assigned target values for 25-hydroxyvitamin D2 [25(OH)D2] and 25-hydroxyvitamin D3 [25(OH)D3] using reference measurement procedures (RMPs). SRM and PT/EQA samples evaluated included SRM 972a (four levels), SRM 2973, six College of American Pathologists (CAP) Accuracy-Based Vitamin D (ABVD) samples, and nine Vitamin D External Quality Assessment Scheme (DEQAS) samples. Results were received from 28 different laboratories using 20 ligand binding assays and 14 LC-MS/MS methods. Using the test assay results for total serum 25(OH)D (i.e., the sum of 25(OH)D2 and 25(OH)D3) determined for the single-donor samples and the RMP target values, the linear regression and 95% prediction intervals (PIs) were calculated. Using a subset of 42 samples that had concentrations of 25(OH)D2 below 30 nmol/L, one or more of the SRM and PT/EQA samples with high concentrations of 25(OH)D2 were deemed non-commutable using 5 of 11 unique ligand binding assays. SRM 972a (level 4), which has high exogenous concentration of 3-epi-25(OH)D3, was deemed non-commutable for 50% of the LC-MS/MS assays.

Diagnostic utility of transcriptome sequencing for rare Mendelian diseases.

PURPOSE: We investigated the value of transcriptome sequencing (RNAseq) in ascertaining the consequence of DNA variants on RNA transcripts to improve the diagnostic rate from exome or genome sequencing for undiagnosed Mendelian diseases spanning a wide spectrum of clinical indications. METHODS: From 234 subjects referred to the Undiagnosed Diseases Network, University of California-Los Angeles clinical site between July 2014 and August 2018, 113 were enrolled for high likelihood of having rare undiagnosed, suspected genetic conditions despite thorough prior clinical evaluation. Exome or genome sequencing and RNAseq were performed, and RNAseq data was integrated with genome sequencing data for DNA variant interpretation genome-wide. RESULTS: The molecular diagnostic rate by exome or genome sequencing was 31%. Integration of RNAseq with genome sequencing resulted in an additional seven cases with clear diagnosis of a known genetic disease. Thus, the overall molecular diagnostic rate was 38%, and 18% of all genetic diagnoses returned required RNAseq to determine variant causality. CONCLUSION: In this rare disease cohort with a wide spectrum of undiagnosed, suspected genetic conditions, RNAseq analysis increased the molecular diagnostic rate above that possible with genome sequencing analysis alone even without availability of the most appropriate tissue type to assess.

Paradox of hypercholesterolaemia in highly trained, keto-adapted athletes.

OBJECTIVE: A growing number of ultra-endurance athletes have switched to a very low-carbohydrate/high-fat eating pattern. We compared markers of cholesterol and the lipoprotein profile in a group of elite ultra-runners consuming a high-carbohydrate (HC) or low-carbohydrate (LC) diet. METHODS: Fasting blood was obtained from competitive male ultra-endurance runners habitually consuming a very low-carbohydrate (LC; n=10) or high-carbohydrate (HC; n=10) diet to determine blood cholesterol profile, lipoprotein particle distribution and sterol biomarkers of cholesterol balance. RESULTS: Plasma total cholesterol, low-density lipoprotein (LDL-C) and high-density lipoprotein (HDL-C) cholesterol were all significantly greater (p<0.000) in the LC group (65%, 83% and 60%, respectively). There were also significant differences in lipoprotein particle distribution as evidenced by a greater size and concentration of large HDL and LDL particles, and total LDL particle concentration was significantly greater in the LC group, but they had significantly fewer small LDL particles. CONCLUSION: Ultra-endurance athletes habitually consuming a very low-carbohydrate/high-fat diet for over a year showed unique cholesterol profiles characterised by consistently higher plasma LDL-C and HDL-C, less small LDL particles, and lipoprotein profiles consistent with higher insulin sensitivity. There may be a functional purpose to the expansion of the circulating cholesterol pool to meet the heightened demand for lipid transport in highly trained, keto-adapted athletes.

Eradicating medical student mistreatment: a longitudinal study of one institution's efforts.

PURPOSE: Since 1995, the David Geffen School of Medicine at UCLA (DGSOM) has created policies to prevent medical student mistreatment, instituted safe mechanisms for reporting mistreatment, provided resources for discussion and resolution, and educated faculty and residents. In this study, the authors examined the incidence, severity, and sources of perceived mistreatment over the 13-year period during which these measures were implemented. METHOD: From 1996 to 2008, medical students at DGSOM completed an anonymous survey after their third-year clerkships and reported how often they experienced physical, verbal, sexual harassment, ethnic, and power mistreatment, and who committed it. The authors analyzed these data using descriptive statistics and the students' descriptions of these incidents qualitatively, categorizing them as "mild," "moderate," or "severe." They compared the data across four periods, delineated by milestone institutional measures to eradicate mistreatment. RESULTS: Of 2,151 eligible students, 1,946 (90%) completed the survey. More than half (1,166/1,946) experienced some form of mistreatment. Verbal and power mistreatment were most common, but 5% of students (104/1,930) reported physical mistreatment. The pattern of incidents categorized as "mild," "moderate," or "severe" remained across the four study periods. Students most frequently identified residents and clinical faculty as the sources of mistreatment. CONCLUSIONS: Despite a multipronged approach at DGSOM across a 13-year period to eradicate medical student mistreatment, it persists. Aspects of the hidden curriculum may be undermining these efforts. Thus, eliminating mistreatment requires an aggressive approach both locally at the institution level and nationally across institutions.

Educational Experiences Residents Perceive As Most Helpful for the Acquisition of the ACGME Competencies.

BACKGROUND: The Accreditation Council for Graduate Medical Education (ACGME) requires physicians in training to be educated in 6 competencies considered important for independent medical practice. There is little information about the experiences that residents feel contribute most to the acquisition of the competencies. OBJECTIVE: To understand how residents perceive their learning of the ACGME competencies and to determine which educational activities were most helpful in acquiring these competencies. METHOD: A web-based survey created by the graduate medical education office for institutional program monitoring and evaluation was sent to all residents in ACGME-accredited programs at the David Geffen School of Medicine, University of California-Los Angeles, from 2007 to 2010. Residents responded to questions about the adequacy of their learning for each of the 6 competencies and which learning activities were most helpful in competency acquisition. RESULTS: We analyzed 1378 responses collected from postgraduate year-1 (PGY-1) to PGY-3 residents in 12 different residency programs, surveyed between 2007 and 2010. The overall response rate varied by year (66%-82%). Most residents (80%-97%) stated that their learning of the 6 ACGME competencies was "adequate." Patient care activities and observation of attending physicians and peers were listed as the 2 most helpful learning activities for acquiring the 6 competencies. CONCLUSION: Our findings reinforce the importance of learning from role models during patient care activities and the heterogeneity of learning activities needed for acquiring all 6 competencies.

Enhancing the reliability of the multiple mini-interview for selecting prospective health care leaders.

PURPOSE: The David Geffen School of Medicine at UCLA Program in Medical Education (UCLA-PRIME) used a 12-station multiple mini-interview (MMI) circuit to assess applicants. The authors sought to determine the reliability of the MMI, potential bias in scores, and the degree of acceptance by interviewers and applicants. METHOD: In 2009, 28 interviewers interviewed a cohort of 76 applicants. An anonymous survey assessed interviewers' and applicants' satisfaction with the MMI process and perceived bias. Psychometric properties were determined with generalizability and decision theory. The process was repeated the following year with a new cohort of 78 applicants and minor modifications aimed at improving reliability. RESULTS: The MMI format was well received by both applicants and interviewers. No bias based on gender or disadvantaged status was found. The preliminary reliability of the MMI in 2009 was 0.58-lower than reported in previous studies-but improved in 2010 to 0.71 after an easy station was replaced with a more challenging one and a new scoring rubric was introduced. CONCLUSIONS: This interview technique proved to be reliable and was seen as transparent, uniform, and fair. The predictive validity of this process remains to be determined.

Numerical Versus Pass/Fail Scoring on the USMLE: What Do Medical Students and Residents Want and Why?

BACKGROUND: Although the primary purpose of the US Medical Licensing Examination (USMLE) is assessment for licensure, USMLE scores often are used for other purposes, more prominently resident selection. The Committee to Evaluate the USMLE Program currently is considering a number of substantial changes, including conversion to pass/fail scoring. METHODS: A survey was administered to third-year (MS3) and fourth-year (MS4) medical students and residents at a single institution to evaluate opinions regarding pass/fail scoring on the USMLE. RESULTS: Response rate was 59% (n  =  732 of 1249). Reported score distribution for Step 1 was 30% for <220, 38% for 220-240, and 32% for >240, with no difference between MS3s, MS4s, and residents (P  =  .89). Score distribution for Step 2 Clinical Knowledge (CK) was similar. Only 26% of respondents agreed that Step 1 should be pass/fail; 38% agreed with pass/fail scoring for Step 2 CK. Numerical scoring on Step 1 was preferred by respondents who: (1) agreed that the examination gave an accurate estimate of knowledge (odds ratio [OR], 4.23; confidence interval [CI], 2.41-7.43; P < .001); (2) scored >240 (OR, 4.0; CI, 1.92-8.33; P < .001); and (3) felt that acquisition of knowledge might decrease if the examination were pass/fail (OR, 10.15; CI, 3.32-31.02; P < .001). For Step 2 CK, numerical scoring was preferred by respondents who: (1) believed they gained a large amount of knowledge preparing for the examination (OR, 2.63; CI, 1.52-4.76; P < .001); (2) scored >240 (OR, 4.76; CI, 2.86-8.33; P < .001); (3) felt that the amount of knowledge acquired might decrease if it were pass/fail (OR, 28.16; CI, 7.31-108.43; P < .001); and (4) believed their Step 2 CK score was important when applying for residency (OR, 2.37; CI, 1.47-3.84; P < .001). CONCLUSIONS: Students and residents prefer the ongoing use of numerical scoring because they believe that scores are important in residency selection, that residency applicants are advantaged by examination scores, and that scores provide an important impetus to review and solidify medical knowledge.

A serosurvey of Coxiella burnetii infection in children and young adults in South West Queensland.

OBJECTIVE: To describe the seroepidemiology of Coxiella burnetii, the causative agent of Q fever, in those under 25 years of age in South West Queensland. METHODS: A convenience sample of residual sera from a diagnostic laboratory was tested for C. burnetii antibodies by immunofluorescence at 1:10 dilution. Prevalence and annual incidence were calculated from the results. RESULTS: Twenty-nine of 447 (6.5%, 95% CI 4.5%-9.2%) samples were positive. Seropositivity increased from 2.5% in those <15 (95% CI 1.0%-5.5%) to 11.0% in those 15-24 years old (95% CI 7.4%-16.0%). The estimated annual incidence for the latter age group was 7.7 per 1,000. CONCLUSIONS: Q fever is a relatively common infection in South West Queensland, even in those aged <15 years for whom the vaccine is not recommended. IMPLICATIONS: Vaccination programs, such as the federally funded National Q fever Management Program, are needed in this and similar high risk rural areas.

Q fever.

Q fever is a zoonosis with many manifestations. The most common clinical presentation is an influenza-like illness with varying degrees of pneumonia and hepatitis. Although acute disease is usually self-limiting, people do occasionally die from this condition. Endocarditis is the most frequent chronic presentation. Although Q fever is widespread, practitioner awareness and clinical manifestations vary from region to region. Geographically limited studies suggest that chronic fatigue syndrome and cardiovascular disease are long-term sequelae. An effective whole-cell vaccine is licensed in Australia. Live and acellular vaccines have also been studied, but are not currently licensed.