Improving diagnosis and treatment of hypomagnesemia.

Magnesium is one of the most abundant cations in the body and acts as a cofactor in more than 600 biochemical reactions. Hypomagnesemia is a highly prevalent condition, especially in subjects with comorbid conditions, but has received less attention than other electrolyte disturbances. This review will discuss magnesium physiology, absorption, storage, distribution across the body, and kidney excretion. After reviewing the regulation of magnesium homeostasis, we will focus on the etiology and clinical presentation of hypomagnesemia. The role of laboratory medicine in hypomagnesemia will be the main purpose of this review, and we will discuss the laboratory tests and different samples and methods for its measurement. Although free magnesium is physiologically active, total serum magnesium is the most commonly used measurement in laboratory medicine and is apt for clinical purposes; however, it is not appropriately used, and many patients with hypomagnesemia remain undiagnosed and not treated. Using information technologies, laboratory medicine can largely improve the diagnosis and treatment of hypomagnesemia through the design and establishment of automatic demand management and result management interventions by acting in the first and last steps of the laboratory cycle, test requests, and actions taken after test results, to unmask patients with hypomagnesemia and improve the number of patients undergoing treatment.

Early Brain Amyloid Accumulation at PET in Military Instructors Exposed to Subconcussive Blast Injuries.

Background Traumatic brain injury (TBI) is the leading cause of disability in young adults. Recurrent TBI is associated with a range of neurologic sequelae, but the contributing factors behind the development of such chronic encephalopathy are poorly understood. Purpose To quantify early amyloid ß deposition in the brain of otherwise healthy adult men exposed to repeated subconcussive blast injury using amyloid PET. Materials and Methods In this prospective study from January 2020 to December 2021, military instructors who were routinely exposed to repeated blast events were evaluated at two different points: baseline (before blast exposure from breacher or grenade) and approximately 5 months after baseline (after blast exposure). Age-matched healthy control participants not exposed to blasts and without a history of brain injury were evaluated at similar two points. Neurocognitive evaluation was performed with standard neuropsychologic testing in both groups. Analysis of PET data consisted of standardized uptake value measurements in six relevant brain regions and a whole-brain voxel-based statistical approach. Results Participants were men (nine control participants [median age, 33 years; IQR, 32-36 years] and nine blast-exposed participants [median age, 33 years; IQR, 30-34 years]; P = .82). In the blast-exposed participants, four brain regions showed significantly increased amyloid deposition after blast exposure: inferomedial frontal lobe (P = .004), precuneus (P = .02), anterior cingulum (P = .002), and superior parietal lobule (P = .003). No amyloid deposition was observed in the control participants. Discriminant analysis on the basis of regional changes of amyloid accumulation correctly classified the nine healthy control participants as healthy control participants (100%), and seven of the nine blast-exposed participants (78%) were correctly classified as blast exposed. Based on the voxel-based analysis, whole-brain parametric maps of early abnormal early amyloid uptake were obtained. Conclusion Early brain amyloid accumulation was identified and quantified at PET in otherwise healthy adult men exposed to repetitive subconcussive traumatic events. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Haller in this issue.

Unusually High Prevalence of Stroke and Cerebral Vasculopathy in Hemoglobin SC Disease: A Retrospective Single Institution Study.

INTRODUCTION: Unlike homozygous hemoglobin SS (HbSS) disease, stroke is a rare complication in hemoglobin SC (HbSC) disease. However, recent studies have demonstrated a high prevalence of silent stroke in HbSC disease. The factors associated with stroke and cerebral vasculopathy in the HbSC population are unknown. METHODS: We conducted a retrospective study of all patients with sickle cell disease treated at the University of Missouri, Columbia, over an 18-year period (2000-2018). The goal of the study was to characterize the silent, overt stroke, and cerebral vasculopathy in HbSC patients and compare them to patients with HbSS and HbS/ß thalassemia1 (thal) in this cohort. We also analyzed the laboratory and clinical factors associated with stroke and cerebral vasculopathy in the HbSC population. RESULTS: Of the 34 HbSC individuals, we found that the overall prevalence of stroke and cerebral vasculopathy was 17.7%. Only females had evidence of stroke or cerebral vasculopathy in our HbSC cohort (33.3%, p = 0.019). Time-averaged means of maximum velocities were lower in the HbSC group than the HbSS group and did not correlate with stroke outcome. Among HbSC individuals, those with stroke and cerebral vasculopathy had a marginally higher serum creatinine than those without these complications (0.77 mg/dL vs. 0.88 mg/dL, p = 0.08). Stroke outcome was associated with recurrent vaso-occlusive pain crises (Rec VOCs) (75 vs. 25%, p = 0.003) in HbSC patients. The predominant cerebrovascular lesions in HbSC included microhemorrhages and leukoencephalopathy. CONCLUSION: There is a distinct subset of individuals with HbSC who developed overt, silent stroke, and cerebral vasculopathy. A female predominance and association with Rec VOCs were identified in our cohort; however, larger clinical trials are needed to identify and confirm specific clinical and laboratory markers associated with stroke and vasculopathy in HbSC disease.

The clinical laboratory: a decision maker hub.

OBJECTIVES: We aimed to share a new laboratory model based on laboratory knowledge, meaningful use of information technology, and partnership with clinicians, to lead the appropriate use of laboratory testing and clinical decision making in the diagnosis of as-yet-undiagnosed disease. More specifically, we evaluate the role of eight different opportunistic interventions to diagnose certain asymptomatic disorders, by means of the automatic registration of appropriate laboratory testing according to different scenarios. METHODS: This is a retrospective longitudinal study to evaluate the impact of laboratory interventions on the diagnosis of different diseases and on patient care, including data from January 2012 to September 2020. RESULTS: Overall, the above strategies have so far identified 2063 patients with clinically relevant as-yet-undiagnosed disorders who would have otherwise remained occult, such as for instance, primary hyperparathyroidism, diabetes, and hypomagnesemia. CONCLUSIONS: We are facing a new laboratory model, a leading laboratory rather than a passive traditional laboratory, not just to intervene in clinical decision-making, but to make the clinical decision, through the identification of patients with occult disease.

High frequency of anti-parietal cell antibody (APCA) and intrinsic factor blocking antibody (IFBA) in individuals with severe vitamin B12 deficiency - an observational study in primary care patients.

Background Vitamin B12 deficiency is common worldwide and is also linked to several diseases including autoimmune atrophic gastritis (AAG). The presence of anti-parietal cell antibodies (APCA) and/or intrinsic factor blocking antibodies (IFBA) is indicative of AAG that may develop into pernicious anemia. Both conditions are known to be associated with an increased risk of gastric carcinoma. The aim of this study was to estimate the frequency of individuals positive for APCA and IFBA antibodies in primary care patients with severe vitamin B12 deficiency. Methods An observational study was designed and 5468 consecutive patients from primary care with a request for vitamin B12 status were included and add-on testing for APCA and IFBA that were automatically registered if severe vitamin B12 deficiency was identified (<73.8 pmol/L). For patients included in the intervention, study demographic data, mean corpuscular volume (MCV) and hemoglobin values were collected. Results Seventy-seven patients with severe vitamin B12 deficiency were identified and out of these 44 (57%) presented with antibodies to APCA and 11 (14%) to IFBA, 25 (32.5%) had anemia, and 25 (32.5%) had macrocytosis. The majority of APCA and/or IFBA positive patients were found in the age group >70 years. Both anemia and macrocytosis were more common among APCA positive patients but the association was not statistically significant, neither was the correlation between IFBA status and anemia and/or macrocytosis. Among the patients with anemia, 10 (39%) had macrocytosis, although the rate of macrocytosis among patients with or without anemia did not differ significantly. Conclusions The automated analysis strategy of measuring antibodies to APCA and IFBA in patients with severe vitamin B12 deficiency, efficiently detected positivity in more than 60% the patients. The result point to the presence of a high rate of otherwise undetected AAG and the potential clinical utility of APCA and IFBA as markers in primary care.

FDG PET/MRI Coregistration Helps Predict Response to Gamma Knife Radiosurgery in Patients With Brain Metastases.

OBJECTIVE: The purpose of this study was to determine whether relative standardized uptake value (SUV) measurements at FDG PET/MRI coregistration are predictive of local tumor control in patients with brain metastases treated with stereotactic radiosurgery (SRS). MATERIALS AND METHODS: A retrospective review was conducted of the images and clinical characteristics of a cohort of patients with brain metastases from non-CNS neoplasms treated with gamma knife radiosurgery (GKRS) who underwent posttherapy FDG PET because of MRI findings concerning for progression. The PET and contrast-enhanced MR images were fused. Relative SUV measurements were calculated from ROIs placed in the area of highest FDG uptake within the enhancing lesion and in the contralateral normal-appearing white matter. Relative SUV was defined as the ratio of maximum SUV in the tumor to maximum SUV in healthy white matter. Two independent readers evaluated response to GKRS using serial posttherapy MRI performed at least 3 months after GKRS completion. The relation between relative SUV and local tumor progression was evaluated with respect to treatment effect. RESULTS: Eighty-five patients (48 [56.5%] women, 37 [43.5%] men; mean age at diagnosis, 60.5 ± 11.3 years) met the inclusion criteria. Thirty-three (38.8%) lesions progressed after SRS. There was a significant association between relative SUV and local tumor control (p = 0.035). Relative SUV provided a diagnostic ROC AUC of 0.67 (95% CI, 0.55-0.79). CONCLUSION: Quantitative relative SUV at posttherapy FDG PET serves as a biomarker of response to SRS in patients with brain metastases in cases in which lesion growth is identified at follow-up MRI. This prognostic data may affect management, supporting the need for further therapeutic actions for selected patients.

Unenhanced MRI as an Alternative to 99mTc-Labeled Dimercaptosuccinic Acid Scintigraphy in the Detection of Pediatric Renal Scarring.

OBJECTIVE: The purpose of this study was to determine whether unenhanced MRI without sedation is a feasible substitute for dimercaptosuccinic acid (DMSA) scintigraphy in the detection of renal scars in pediatric patients. SUBJECTS AND METHODS: Patients scheduled for 99mTc-labeled DMSA scintigraphy for assessment of possible renal scars were recruited to undergo unenhanced MRI (free-breathing fat-suppressed T2-weighted single-shot turbo spin-echo and T1-weighted gradient-echo imaging, 13 minutes' total imaging time). Scintigraphic and MRI studies were evaluated by two independent blinded specialty-based radiologists. For each imaging examination, readers identified scars in upper, middle, and lower kidney zones and rated their diagnostic confidence and the quality of each study. The scintigraphic readers' consensus score opinion for the presence of scars was considered the reference standard. RESULTS: DMSA scintigraphy showed scarring in 19 of the 78 (24.4%) evaluated zones and MRI in 18 of the 78 (23.1%). The two MRI readers found mean sensitivities of 94.7% and 89.5%, identical specificities of 100%, and diagnostic accuracies of 98.7% and 97.4%. Interobserver agreement was 98.7% for MRI and 92.3% for DMSA scintigraphy. The MRI readers were significantly more confident in determining the absence rather than the presence of scars (p = 0.02). MRI readers were more likely to rate study quality as excellent (84.6%) than were the scintigraphic readers (57.7%) (p = 0.024). CONCLUSION: Unenhanced MRI has excellent sensitivity, specificity, diagnostic accuracy, and interobserver agreement for detecting renal scars in older children who do not need sedation. It may serve as a substitute modality, especially when DMSA is not available.

Urinary albumin strip assay as a screening test to replace quantitative technology in certain conditions.

Background The clinical laboratory plays a crucial role in the diagnosis and monitoring of chronic kidney disease. The quantitative measurement of urine albumin in a spot sample, expressed as ratio per creatinine (ACR) is the most frequently used biomarker for such a purpose. Our aim was to evaluate the diagnostic performances of a strip for measuring ACR for differentiating patients who are candidates for subsequent albumin quantification, and to evaluate the economic effects of its implementation. Methods We systematically measured strip analysis when quantitative urinary albumin was requested. Semiquantitative urinary albumin was measured using a UC-3500 (Sysmex, Kobe, Japan), based on the protein error of a pH indicator. We collected and reviewed all the values of quantified urinary albumin and their corresponding results in ACR strip tests. We calculated the diagnostic indicators for ACR at different albumin and creatinine values using the quantitative ACR measurement as a "gold standard". We also studied the economic effects based on both tests prices (€1.31 for quantitative albumin plus creatinine, and €0.04 for an albumin strip). Results The study included 9148 patients (mean age 63, 46.3% men). The results at different albumin and creatinine cutoffs showed the best performance when 10 mg/L and above 50 mg/dL, respectively. Based on our results, we would have saved 3506 urine albumin and creatinine tests in the study period, corresponding to €4226.94. Conclusions The present study supports the use of the ACR strip test to identify pathological albuminuria values to be measured through quantitative methods. Considerable economic savings are possible.

Computer-assisted interventions in the clinical laboratory process improve the diagnosis and treatment of severe vitamin B12 deficiency.

BACKGROUND: Severe vitamin B12 deficiency can result in serious complications if undiagnosed or untreated. Our aim was to test the efficacy of interventions in the laboratory process to improve the detection and the treatment of severe vitamin B12 deficiency. METHODS: Quasi-experimental investigation with a retrospective 7-year pre-intervention period and 29-month post-intervention follow-up in a university hospital. Two interventions were designed to improve the detection and treatment of subjects with vitamin B12 deficiency: the laboratory information system (LIS) automatically added seru vitamin B12 (s-vitamin B12) based on certain conditions; and created a comment in the report and scheduled an appointment with the general practitioner (GP). We calculated the number of new diagnoses of severe vitamin deficiency (s-vitamin B12 <73.8 pmol/L) and the proportion of identified patients that were correctly treated in the pre- and post-intervention periods. We compared the number of tests needed to detect a new case when ordered by GPs vs. added by the strategy. Finally, we investigated the economic cost of each new case. RESULTS: The strategy added 699 s-vitamin B12 and detected 66 new cases of severe vitamin deficiency. The number of tests needed to identify a new case when s-vitamin B12 was ordered by GPs was 187, as opposed to 10 when added through the intervention (p<0.001). The intervention reagent cost was €26.7 per new case. In the post-intervention cohort, 88% of patients were correctly treated, as opposed to 52% in the pre-intervention (p<0.001). CONCLUSIONS: Interventions in the clinical laboratory process improved the diagnosis and treatment of severe vitamin B12 deficiency.

Request Pattern, Pre-Analytical and Analytical Conditions of Urinalysis in Primary Care: Lessons from a One-Year Large-Scale Multicenter Study.

BACKGROUND: To study the urinalysis request, pre-analytical sample conditions, and analytical procedures. METHODS: Laboratories were asked to provide the number of primary care urinalyses requested, and to fill out a questionnaire regarding pre-analytical conditions and analytical procedures. RESULTS: 110 laboratories participated in the study. 232.5 urinalyses/1,000 inhabitants were reported. 75.4% used the first morning urine. The sample reached the laboratory in less than 2 hours in 18.8%, between 2 - 4 hours in 78.3%, and between 4 - 6 hours in the remaining 2.9%. 92.5% combined the use of test strip and particle analysis, and only 7.5% used the strip exclusively. All participants except one performed automated particle analysis depending on strip results; in 16.2% the procedure was only manual. CONCLUSIONS: Urinalysis was highly requested. There was a lack of compliance with guidelines regarding time between micturition and analysis that usually involved the combination of strip followed by particle analysis.

Glycated hemoglobin: A powerful tool not used enough in primary care.

BACKGROUND: Glycated haemoglobin (HbA1c) is one of the most useful and relevant laboratory tests currently available. The aim of the actual research was to study the variability and appropriateness in the request of HbA1c in primary care, and differences between regions, to assess if there would be an opportunity to improve the request. METHODS: A cross-sectional study was conducted enrolling clinical Spanish laboratories. The number of HbA1c requested in 2014 by all general practitioners was reported by each participant. Test-utilization rate was expressed as tests per 1000 inhabitants. The index of variability was calculated, as the top decile divided by the bottom decile. HbA1c per 1000 inhabitants was compared between the different regions. To investigate whether HbA1c was appropriately requested to manage patients with diabetes, the real request was compared to the theoretically ideal number, according to prevalence of known diabetes mellitus in Spain and guideline recommendations. RESULTS: A total of 110 laboratories participated in the study, corresponding to a catchment area of 27 798 262 inhabitants (59.8% of the Spanish population) from 15 different autonomous communities (AACCs). 2 655 547 HbA1c were requested, a median of 93.9 (interquartile range (IQR): 33.4) per 1000 inhabitants. The variability index was 1.97. The HbA1c/1000 inhabitants was significantly different among the AACCs, ranging from 73.4 to 126.3. A total of 4 336 529 additional HbA1c would have been necessary to manage patients with diabetes according to guidelines, and 3 861 769 for diagnosis in asymptomatic patients. CONCLUSIONS: There was a high variability and significant differences between Spanish AACCs. Also a significant under-request of HbA1c was observed in Primary Care in Spain.

FDG PET/MR Imaging Coregistration Helps Predict Survival in Patients with Glioblastoma and Radiologic Progression after Standard of Care Treatment.

Purpose To determine the correlation between metabolic activity at fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and survival in patients with glioblastoma and suspected progression at posttherapy magnetic resonance (MR) imaging. Materials and Methods The authors retrospectively examined the relationship between metabolic activity at FDG PET in the residual lesion identified at brain MR imaging and survival time in 56 patients with glioblastoma who were treated with postoperative concurrent radiation and temozolomide therapy and who underwent FDG PET/computed tomography because of radiologic deterioration at follow-up MR imaging between 2006 and 2015. A normalized metric of metabolic activity in the residual lesion (standardized uptake value ratio [SUVr]) was calculated as the maximum standardized uptake value (SUVmax) in the tumor relative to that in healthy white matter. The primary end point of the study was survival time from PET. Patients were stratified according to SUVr. Comparisons of risk for death between subgroups were made with the log-hazard ratio of the Cox proportional hazard model. Results There was a significant association between overall survival and SUVr in the residual lesion (P = .006), and a survival benefit was observed in patients with SUVr of less than 1.7, who had a median survival time of 23.1 months (95% confidence interval [CI]: 12.7, 38.9), which was significantly longer than that in patients with an SUVr of 2.0 to less than 2.5 and those with an SUVr of at least 2.5, who had a median survival time of 10.1 (95% CI: 2.4, 15.9; P = .008) and 7.5 (95% CI: 3.9, 9.7; P < .001) months, respectively. Conclusion Patients with glioblastoma whose posttherapy MR images showed a residual lesion with high relative metabolic activity at FDG PET had a shorter survival time than did those with low activity at FDG PET. © RSNA, 2016.

Temporal and regional variability in the request of vitamin D from general practitioners in Spain.

BACKGROUND: Our main goal is to study the inter-practice regional variability and the temporal evolution in the request of 25-hydroxyvitamin D (25[OH]D) by general practitioners (GPs) in Spain. METHODS: Clinical laboratories in different autonomic communities (AACCs) were invited to report the number of 25(OH)D test requested by GPs during 2012 and 2014. The number of 25(OH)D requested per 1000 inhabitants and the index of variability were calculated, and compared between regions and time periods. We calculated the number of tests that could have been potentially saved in regions where 25(OH)D could be requested from primary care without restrictions taking into account the request in those where it is restricted, and the potential economical savings. RESULTS: Seventy-six laboratories participated in the 2012 edition, and 110 in 2014, corresponding to 17,679,195 and 27,798,262 inhabitants (59.8% Spanish population). The number of 25(OH)D requested per 1000 inhabitants increased from 1.1 in 2012 to 3.4 in 2014 (p<0.001). The variability index also increased from 51.7 to 68. There was a significantly variability among the different AACCs, ranging from 0.94 to 21.24 (p=0.002). 173,885 tests could have been not measured from primary care in regions without ordering restrictions, resulting in potential 886,813.5€ savings. CONCLUSIONS: There was a high variability in the request of 25(OH)D by GPs in Spain, which significantly increased in a 2 year period. The demand was higher in areas where the request of 25(OH)D was not restricted in primary care, with potential savings if the request would approach to regions with ordering restrictions.

Uncritical Request of Thyroid Laboratory Tests May Result in a Major Societal Economic Burden: Results from a Large Population Study in Spain.

BACKGROUND: Our aim is to study the regional variability in the request of thyroid laboratory tests from primary care facilities in Spain and to investigate a potential inappropriate request and its economic societal impact. METHODS: Spain is divided into 17 autonomous communities (AACCs) which are in turn divided in Health Departments that cover a geographic area and its population and a laboratory that attends the needs of every inhabitant. Each participating laboratory was required to report the number of thyroid tests requested from primary care during year 2014 and to provide organizational data. The request of every test per 1000 inhabitants and ratio of related tests (free thyroxine (FT4)/thyrotropin (TSH), triiodothironine (FT3)/TSH, antithyroglobulin antibody (ATG)/antiperoxidase antibody (TPO)) were calculated and compared in different AACCs with more than 4 participants. The economic costs taking into account reagent cost were calculated. RESULTS: 110 laboratories participated (27,798,262 inhabitants). Close to 6 million TSH tests were requested, representing an expense of more than 10 million euros. That corresponds to 18 million euros when extrapolating for the whole Spanish population, only in reagent cost. The number of TSH requests per 1000 inhabitants in the different AACCs ranged from 198 to 289. FT4 was ordered more than twice as frequently in some regions compared to others. TPO request per 1000 inhabitants ranged from 0.2 to 11.2. CONCLUSIONS: There was a significant over-request and regional variability of thyroid laboratory tests in primary care in Spain, resulting in a high economic impact on society.

Prediction of Early Arterial Recanalization and Tissue Fate in the Selection of Patients With the Greatest Potential to Benefit From Intravenous Tissue-Type Plasminogen Activator.

BACKGROUND AND PURPOSE: Our objective is to determine the performance of the combination of likelihood of arterial recanalization and tissue fate to predict functional clinical outcome in patients with acute stroke. METHODS: Clinical, imaging, and outcome data were collected in 173 patients with acute ischemic stroke who presented within 4.5 hours from symptom onset, in the time window eligible for intravenous tissue-type plasminogen activator. Imaging data included Alberta Score Program Early Computed Tomographic Score (ASPECTS), site of occlusion, volume of ischemic core and penumbra, and recanalization. Outcome data consisted of modified Rankin Scale score at 90 days. We classified patients based on their baseline imaging characteristics and treatment with intravenous tissue-type plasminogen activator (yes/no) according to 5 different hypothetical prognostic algorithms: (1) based on whether patients received intravenous tissue-type plasminogen activator, (2) based on ASPECTS, (3) based on the site of occlusion, (4) based on volume of ischemic core and penumbra, and (5) based on a matrix of predicted recanalization and volume of ischemic core and penumbra. We compared the performance of such algorithms to predict good clinical outcome, defined as modified Rankin Scale score of ≤2 at 90 days. RESULTS: One hundred and twenty-four patients received intravenous tissue-type plasminogen activator; 49 did not. In the group that was treated, 46 (37%) had good outcome as opposed to 38.7% in the nontreated. The algorithm that combined the prediction of recanalization with the volume of ischemic core and penumbra showed the highest accuracy to predict good outcome (77.7%) as opposed to others (range, 43.9%-57.2%) CONCLUSIONS: The combination of predicted recanalization and tissue fate proved superior to prognosticate good clinical outcome when compared with other usual predictors.

Detection of parathyroid adenomas using a monophasic dual-energy computed tomography acquisition: diagnostic performance and potential radiation dose reduction.

INTRODUCTION: The aims of the study were to compare the diagnostic performance of a combination of virtual non-contrast (VNC) images and arterial images obtained from a single-phase dual-energy CT (DECT) acquisition and standard non-contrast and arterial images from a biphasic protocol and to study the potential radiation dose reduction of the former approach. METHODS: All DECT examinations performed for evaluation of parathyroid adenomas during a 13-month period were retrospectively reviewed. An initial single-energy unenhanced acquisition was followed by a dual-energy arterial phase acquisition. "Virtual non-contrast images" were generated from the dual-energy acquisition. Two independent and blinded radiologists evaluated three different sets of images during three reading sessions: single arterial phase, single-phase DECT (virtual non-contrast and arterial phase), and standard biphasic protocol (true non-contrast and arterial phase). The accuracy of interpretation in lateralizing an adenoma to the side of the neck and localizing it to a quadrant in the neck was evaluated. RESULTS: Sixty patients (mean age, 65.5 years; age range, 38-87 years) were included in the study. The lateralization and localization accuracy, sensitivity, and positive predicted value (PPV) and negative predicted value (NPV) of the different image datasets were comparable. The combination of VNC and arterial images was more specific than arterial images alone to lateralize a parathyroid lesion (OR = 1.93, p = 0.043). The use of the single-phase protocol resulted in a calculated radiation exposure reduction of 52.8 %. CONCLUSIONS: Virtual non-contrast and arterial images from a single DECT acquisition showed similar diagnostic accuracy than a biphasic protocol, providing a significant dose reduction.

Requests of laboratory tests for the diagnosis and management of calcium-phosphate disorders in Spain.

BACKGROUND: Knowledge about the variability in the request of calcium-phosphate metabolism laboratory tests in primary care is important to design strategies to improve health system efficiency. AIM: To compare the inter-practice variability in calcium-phosphate metabolism laboratory tests requested by general practitioners from diverse regions across Spain. MATERIAL AND METHODS: One hundred and forty one clinical laboratories were invited to participate in an observational cross-sectional study. They informed the number of serum calcium, phosphate, parathyroid hormone and 25-hydroxyvitamin D requested by general practitioners. Appropriateness indicators were calculated as number of test requests per 1,000 inhabitants and ratio of related tests requests. The differences according to hospital setting, region and type of management were analyzed. RESULTS: We recruited 76 laboratories (17,679,195 inhabitants). General practitioners requested 3,260,894 calcium-phosphate metabolism tests. The rate of request ranged from 2.97 per 1,000 inhabitants for 25-hydroxyvitamin D to 98.89 per 1,000 inhabitants for calcium. The rates of request for calcium, phosphate, parathyroid hormone in some areas were 30, 100 and 340 times higher than in other areas. Parathyroid hormone and 25-hydroxyvitamin D were highly requested in private management areas. There were also differences in phosphate, parathyroid hormone and 25-hydroxyvitamin D requesting between regions across Spain. CONCLUSIONS: The high variability observed is difficult to explain by differences in patient case mix between regions. Depending on the area, calcium could be under requested to detect primary hyperparathyroidism.

Laboratory utilization improvement through a computer-aided algorithm developed with general practitioners.

BACKGROUND: One of the main duties of healthcare workers is to get an appropriate use of diagnostic and therapeutic tools. The aim of this study was to show how strategies can be designed and established in consensus with general practitioners (GPs) to reach an optimal laboratory test request. METHODS: The laboratory serves a population of approximately 235,000 inhabitants, including nine primary care centers. GPs could request every test in profiles and individually. In meetings between the laboratory and GPs our request patterns were compared to other geographic regions, and we investigated the appropriateness of test requesting. The group devised strategies that consisted of removing tests from profiles [aspartate aminotransferase (AST), γ-glutamyltranspeptidase (GGT) and phosphate], removing tests from GPs requests (iron and transferrin), substituting tests (IgA antigliadin antibody), and measuring total bilirubin (tBil) only when the icteric index value was above 34.2 mmol/L (2 mg/dL). We analyzed every test request in the post- (years 2012-2013) and pre-intervention period (years 2010-2011), and the tBil measured in the post-intervention period. We studied if AST/alanine aminotransferase (ALT) and GGT/ALT achieved indicators targets and calculated the economic savings in the post-intervention period. RESULTS: There was a significant drop in every test request in the post-intervention period. AST/ALT achieved the indicator target. GGT/ALT, never achieved the indicator goal. The strategies resulted in a savings of more than €34,000. CONCLUSIONS: The strategies designed between the laboratory and the requesting clinicians and automatically established by using our laboratory information system were successful.