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An interlaboratory comparison study was conducted by the Vitamin D Standardization Program (VDSP) to assess the performance of liquid chromatography – tandem mass spectrometry (LC-MS/MS) assays used for the determination of serum total 25-hydroxyvitamin D (25(OH)D), which is the sum of 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3). A set of 50 single-donor samples was assigned target values for concentrations of 25(OH)D2, 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 1 includes results from 14 laboratories using 14 custom LC-MS/MS 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 53% of the LC-MS/MS assays met the VDSP criterion of mean % bias ≤ |±5%|. For the LC-MS/MS assays not meeting the ≤ |±5%| criterion, four assays had mean % bias of between 12 and 21%. Based on multivariable regression analysis using the concentrations of the four individual vitamin D metabolites in the 50 single-donor samples, the performance of several LC-MS/MS assays was found to be influenced by the presence of 3-epi-25(OH)D3. The results of this interlaboratory study represent the most comprehensive comparison of LC-MS/MS assay performance for serum total 25(OH)D and document the significant impact of the lack of separation of 3-epi-25(OH)D3 and 25(OH)D3 on assay performance, particularly with regard to mean % bias.

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.

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.

Background Fear of disease recurrence is well documented among cancer survivors, but its significance among patients treated for solid pancreatic and periampullary neoplasms is unknown despite the known risk of recurrence associated with these tumors. We hypothesized that fear of cancer recurrence (FCR) represents a common source of psychosocial distress in this population and sought to characterize subgroups for whom FCR might represent a target for intervention to improve quality of life. Methods We conducted a cross-sectional study of FCR in patients who were disease-free after potentially curative pancreatectomy for ductal or periampullary adenocarcinoma or pancreatic neuroendocrine tumor. We assessed seven discrete dimensions of FCR using the Fear of Recurrence Inventory and evaluated quality of life and psychosocial distress using the Functional Assessment of Cancer Therapy-Hepatobiliary Questionnaire and the Hospital Anxiety and Depression Scale. Results Of 354 eligible patients, 240 (68 %) participated in the study a median of 48 months after potentially curative pancreatectomy. An FCR severity score indicative of frequent fearful thoughts, emotional disturbance and functional impairment was identified in 37, 28, and 35 % of patients with pancreatic adenocarcinoma, nonpancreatic periampullary adenocarcinoma, and pancreatic neuroendocrine tumor, respectively. Anxiety ( P  < 0.001) and low quality of life ( P  = 0.028) were independently associated with a clinically significant level of FCR, but histopathologic diagnosis and clinicopathologic markers of prognosis were not. Conclusions FCR represents a significant concern for one-third of patients after curative surgery for a pancreatic or periampullary tumor, regardless of their actual likelihood of recurrence or disease-related death.

Objectives To assess the contribution of whole-body magnetic resonance imaging (WBMRI) and bone scintigraphy (BS) in addition to skeletal survey (SS) in detecting traumatic bone lesions and soft-tissue injuries in suspected child abuse. Methods In this prospective, multicentre, diagnostic accuracy study, children less than 3 years of age with suspected physical abuse were recruited. Each child underwent SS, BS and WBMRI. A blinded first review was performed in consensus by five paediatric radiologists and three nuclear medicine physicians. A second review investigated discrepancies reported between the modalities using a consensus result of all modalities as the reference standard. We calculated the sensitivity, specificity and corresponding 95% confidence interval for each imaging modality (SS, WBMRI and BS) and for the combinations [SS + WBMRI] and [SS + BS]. Results One hundred seventy children were included of which sixty-four had at least one lesion. In total, 146 lesions were included. The sensitivity and specificity of each examination were, respectively, as follows: 88.4% [95% CI, 82.0–93.1] and 99.7% [95% CI, 99.5–99.8] for the SS, 69.9% [95% CI, 61.7–77.2] and 99.5% [95% CI, 99.2–99.7] for WBMRI and 54.8% [95% CI, 46.4–63.0] and 99.7% [95% CI, 99.5–99.9] for BS. Sensitivity and specificity were, respectively, 95.9% [95% CI, 91.3–98.5] and 99.2% [95% CI, 98.9–99.4] for the combination SS + WBMRI and 95.2% [95% CI, 90.4–98.1] and 99.4% [95% CI, 99.2–99.6] for the combination SS + BS, with no statistically significant difference between them. Conclusion SS was the most sensitive independent imaging modality; however, the additional combination of either WBMRI or BS examinations offered an increased accuracy. Key Points • SS in suspected infant abuse was the most sensitive independent imaging modality in this study, especially for detecting metaphyseal and rib lesions, and remains essential for evaluation. • The combination of either SS + BS or SS + WBMRI provides greater accuracy in diagnosing occult and equivocal bone injuries in the difficult setting of child abuse. • WBMRI is a free-radiation technique that allows additional diagnosis of soft-tissue and visceral injuries.

We performed a cross-sectional study of fear of cancer recurrence and quality of life among 240 patients who were free of disease following pancreatectomy for a solid pancreatic or periampullary neoplasm. A clinically significant level of fear of cancer recurrence was identified in one-third of patients and it was associated with anxiety and poorer quality of life but was not associated with clinicopathologic markers of prognosis.