Citations

Introduction Pulmonary Embolism (PE) is a major cause of morbidity and mortality worldwide. Diagnosis is essential as untreated PE has a 30% mortality rate. Currently, computer tomography pulmonary angiogram (CTPA) is the standard of care to diagnose PE. However, this modality is expensive, exposes patients to radiation and increases risk of contrast induced nephropathy. Furthermore, only 5% of CTPAs performed are positive for PE signifying that many unnecessary tests are being performed. To address this gap, Pre-Test Probability (PTP) tools have been developed to safely exclude patients with low risk of PE and limit iatrogenic harm from over testing. Despite the tools being developed over 20 years ago, they are not widely available in electronic health record (EHR) systems and even when they are built in, uptake remains low. Methods Three large integrated health systems using Epic EHR systems across five states (MA, WI. MN, AZ, FL) built electronic PTP assessments into their EHR systems to safely exclude patients with low risk of PE and limit over testing. Two sites made the PTP optional, and one site made it a forced function (providers were forced to complete PTP prior to ordering CTPA unless a D-dimer result was present in the prior 48 hours). To assess the usability of these EHR tools, the team conducted a survey with ED clinicians across the three test sites. The survey was created to identify which PE risk stratification methods were employed by ED clinicians (EHR embedded PTP tool, apps on their phone, web applications like MDcalc, calculations from memory, or if they relied on clinical gestalt), and to identify barriers to using the EHR embedded PTP. Results Site 1 had 47 respondents, Site 2 had 94 respondents, and Site 3 had 16 respondents. Two key findings emerged from the survey (Figure 1). First, clinicians used a variety of risk stratification approaches and few of them documented their risk assessments in structured fields in the medical record. Second, clinical gestalt was the most used PE risk stratification approach, and this was true across all three test sites. In addition, the health system with a PTP prompt before clinicians could proceed with CTPA orders (Site 3) did not have a higher percentage of clinicians who reported using the EHR embedded tool than sites that did not prompt clinicians to fill in the PTP. Clinicians cited a variety of different barriers to using the EHR embedded PTP tool (Table 1). Conclusion While many clinicians indicated intermittent use of PTP criteria to aid in the diagnosis of PE, risk factors and scores from phone apps, web tools, and calculations from memory are unlikely to be documented in the patient's medical record, which means that they are not accessible to all members of the ED care team and cannot be used for electronic clinical quality measure. The biggest hurdles to increasing the use of structured PTP assessments in the ED setting to safely exclude PE and limit iatrogenic harm from over testing are (1) obtaining buy-in from ED clinicians that the PTP tools provide value over clinical gestalt, at least for a subset of patients who could most benefit, and (2) identifying best practices for incorporating PTP tools into EHR systems that make the tools easier to access and use 3) developing and implementing effective education and awareness programs around the PTP tools. This survey adds to the body of literature on PTP assessments in the ED setting and can help inform further research that is needed to continue to improve the diagnosis of PE. Funding: This project is funded in part by the Gordon and Betty Moore Foundation through Grant GBMF10778 to the American Society of Hematology.

Abstract Background Published data on the risk of venous thromboembolism (VTE) with coronavirus disease 2019 (COVID-19) vaccines are scarce and inconclusive, leading to an unmet need for further studies. Methods A retrospective, multicentered study of adult patients vaccinated for one of the three approved COVID-19 vaccines in the United States of America and a pre-COVID-19 cohort of patients vaccinated for influenza at two institutions: Mayo Clinic Enterprise sites and the Medical College of Wisconsin, looking at rate of VTE over 90 days. VTE was identified by applying validated natural language processing algorithms to relevant imaging studies. Kaplan–Meier curves were used to evaluate rate of VTE and Cox proportional hazard models for incident VTE after vaccinations. Sensitivity analyses were performed for age, sex, outpatient versus inpatient status, and type of COVID-19 vaccine. Results A total of 911,381 study subjects received COVID-19 vaccine (mean age: 56.8 [standard deviation, SD: 18.3] years, 55.3% females) and 442,612 received influenza vaccine (mean age: 56.5 [SD: 18.3] years, 58.7% females). VTE occurred within 90 days in 1,498 (0.11%) of the total 1,353,993 vaccinations: 882 (0.10%) in the COVID-19 and 616 (0.14%) in the influenza vaccination cohort. After adjusting for confounding variables, there was no difference in VTE event rate after COVID-19 vaccination compared with influenza vaccination (adjusted hazard ratio: 0.95 [95% confidence interval: 0.85–1.05]). No significant difference in VTE rates was observed between the two cohorts on sensitivity analyses. Conclusion In this large cohort of COVID-19-vaccinated patients, risk of VTE at 90 days was low and no different than a pre-COVID-19 cohort of influenza-vaccinated patients.

Abstract Background Clinical laboratories are constantly changing with automated analyzers and total lab automation (TLA) implemented and replaced over time. Some benefits of newer technologies include decreased specimen volume requirements, less need for repeat testing, and greater throughput. Recent implementation of new analyzers and replacement of TLA in the Central Clinical Laboratory (CCL) at Mayo Clinic, Rochester, MN, prompted the laboratory to reassess blood collection volumes for commonly ordered tests. Objectives The aim of this study was to evaluate whether updating the blood collection volumes for clinical chemistry and immunoassay tests performed in the CCL could reduce the volume of blood collected from patients and the number of blood collection tubes utilized. Methods Nearly 100 different serum assays from the CCL test menu were reviewed including the basic and comprehensive metabolic, hepatic function, renal function, electrolyte, and lipid panels as well as thyroid function tests, enzymes, hormones, electrolytes, and iron status tests. Cortisol, ferritin, folate, and Vitamin B12 testing were performed on the Beckman DxI800; all other testing was on Roche Diagnostics Cobas 8000 chemistry (ISE, c701, c502) and immunoassay (e801) analyzers. Updated blood volumes for each assay were calculated utilizing manufacturer’s analytical volumes and “dead volume” requirements. Baseline data retrieved from the laboratory information system (LIS) included blood collection volumes and number of tubes collected for 128 patients with physician-orders for laboratory testing on 5/2/21. The collection logic was then updated in the test LIS environment using the new blood volumes requirements and applied to the same 128 orders. Blood volumes and number of tubes collected per order were compared before and after the volume updates. Results Baseline data from 128 unique orders showed that 414 total tubes were collected with a median(range) of 3 (2–6) tubes per order and 5 (1–18) tests per tube. The total volume of blood requested at baseline was 2065 mL. Post-intervention, 197 tubes were needed with a median(range) of 2 (1–3) tubes per order and 13 (1–30) tests per tube. The total volume of blood requested after updating volumes was 851 mL. Conclusions The practice of reviewing and updating specimen volume requirements when replacing or implementing new analyzers or TLA can greatly reduce the volume of blood collected from patients and the number of blood collection tubes per order. In this study of 128 physician orders for common laboratory tests, updating blood collection information in the LIS reduced the requested blood collection volumes by 59% and decreased the number of blood collection tubes required by 52%. This not only benefits patients because less blood is collected but also conserves blood collection tubes and reduces supply chain demands. Additionally, fewer tubes on the TLA system has the potential to improve throughput and test turnaround time.

Abstract Background Total protein is measured in serum and body fluids as part of routine evaluations of general nutritional status and differentiating exudative and transudative effusions. Spectral interference thresholds for bilirubin (e.g., icterus) is set by assay manufacturers to prevent inaccurate results from being reported. The Roche Cobas serum total protein assay package insert states no significant interference from bilirubin up to an icterus (I) index of 20. Body fluids tend to have lower total protein concentrations; therefore, thresholds were derived during prior validation studies and set to I = 10, a threshold that is exceeded routinely. Laboratories can mitigate some interferences by recollecting (e.g., hemolysis) or ultracentrifuging (e.g., lipemia) specimens. Serial dilutions are another option used; however, it is imperative that the laboratory understands the mechanism of interference and can demonstrate that it is mitigated by sample dilution. The aim of this study was to investigate whether bilirubin interference can be mitigated by sample dilution in pleural fluid, peritoneal fluid, and serum specimens. Methods Residual clinically ordered pleural fluid (n = 3), peritoneal fluid (n = 3), and serum (n = 3) samples submitted for protein testing were split into two equal volume aliquots with concentrations ranging 2.7 to 4.3 g/dL in pleural fluids, 3.9 to 5.4 g/dL in peritoneal fluids, and 3.8 to 11.0 g/dL in serum. One aliquot was spiked (<10% by volume) with a bilirubin conjugate solution (∼1000 mg/dL) to surpass the icterus index threshold (spiked). The second aliquot was spiked with an equal volume of 0.9% saline (control). Total protein was measured on the Roche Cobas c701 instrument in both samples to calculate difference (Spiked-Control). The mean(SD) difference was calculated for each sample type. Each spiked sample was serially diluted (2-fold, 4-fold and 8-fold) with 0.9% saline. Total protein was measured for each diluted sample. Mean(SD) difference was calculated (DilutedX-Control), where X = 2-fold, 4-fold, 8-fold. Linear regression analysis was performed by plotting the measured (x-axis) vs expected (y-axis) total protein concentration. Slope, y-intercept, and R2 were determined from serially diluted samples where the expected concentrations were derived using the spiked concentration to replicate the practice of diluting an icteric sample. Results Bilirubin spiking (average icterus index = 33.5) into pleural fluid, peritoneal fluid, and serum, respectively demonstrated mean(SD) bias (g/dL) = −1.0(0.2), −0.9(0.0), and −0.7(0.0). Subsequent 2-fold dilution demonstrated mean(SD) bias (g/dL) = −1.0(0.2), −1.0(0.0), and −0.8(0.1), 4-fold dilution with mean(SD) bias (g/dL) = −1.1(0.2), −1.0(0.0), and -1.0(0.1), and 8-fold dilution with mean(SD) bias (g/dL) = −1.3(0.2), −1.0(0.0), and −1.4(0.1). Diluting pleural, peritoneal, and serum samples, respectively spiked with bilirubin resulted in slope = 0.99, 1.00, and 0.99; y-intercept = 0.04, 0.01, and 0.07; R2 = 0.99, 0.99, 0.99. Conclusion The dilutions exhibited a linear dilution response, however the dilution results never returned to baseline (non-spiked) concentration. Laboratories should exercise caution when conducting serial dilutions to diminish bilirubin interference in samples when measuring total protein as the mechanism of interference does not appear to be reversible by dilution. This behavior was demonstrated in both body fluids and serum.

Abstract Background Serum cortisol, measured by automated immunoassay, is a rapid test used for the initial assessment of adrenal dysfunction. Physiologic serum cortisol concentrations are influenced by many factors including diurnal variation, stress, and patient age. In the absence of established pediatric reference intervals (RIs), our laboratory has utilized adult RIs to flag pediatric cortisol results as abnormally high or low in the electronic health record. However, pediatric cortisol RIs recently defined by the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) are considerably lower than the adult RIs currently in use. This could cause pediatric cortisol results to be incorrectly flagged as “low” when they are within the age-specific RI and lead to unnecessary follow-up testing. The aim of this study was to determine the impact of implementing CALIPER pediatric cortisol RIs on the rate of “low” result flagging for pediatric patients. Methods AM cortisol results for patients age <18 years reported between 10/2012- 09/2022 were obtained from the Mayo Clinic data repository. These results contained values measured by both Beckman Access (n = 3 818) and Roche Cobas (n = 625) immunoassays. Results classified as abnormal “low” by current adult RIs (Beckman: 7–25 mcg/dL, Roche: 4.8–20 mcg/dL) were compared to results which would flag low according to the appropriate method- and age-specific RIs defined by CALIPER (Beckman: 1-<13 yrs 2.19–12.8 mcg/dL, 13-<16 yrs 3.03–17.1 mcg/dL, 16-<19 yrs 3.78–19.4 mcg/dL; Roche: <1 yr 0.58–17.2 mcg/dL, 1-<12 yrs 2.39–14.9 mcg/dL, 12-<19 yrs 3.63–17.4 mcg/dL). The proportion of results flagging low by adult versus pediatric RI were compared by chi-squared test, with P < 0.05 considered significant. Results For Beckman, the percentages of pediatric patient cortisol results flagging low using the adult RI versus (vs) the pediatric age-specific RI were: 35% vs 7% for 1–12 years of age (P < 0.001, n = 1866), 22% vs 5% for 13–15 years (P < 0.001, n = 966), and 16% vs 5% for 16–18 years (P < 0.001, n = 986). For Roche, the same analysis yielded: 52% vs 9% for 0–1 years (P = 0.001, n = 23), 14% vs 8% for 1–11 years (P = 0.03, n = 238), and 9% vs 6% for 12–18 years (P = 0.16, n = 364). Conclusion The implementation of pediatric RIs for serum cortisol will have a significant impact on the number of “low” result flags for patient results on both Beckman and Roche platforms. Statistically significant decreases in the percentage of low result flags were observed on both platforms for all age ranges except for the age bracket of 12–18 years by Roche. Furthermore, pediatric RIs appeared to produce more consistent rates of abnormal results across methods and age ranges, with all groups flagging low at a rate of 5–9%, whereas the same age ranges with adult RIs flagged at rates ranging from 9–52%. Lowering the RIs for pediatric cortisol to more appropriate ranges as identified by CALIPER will decrease the number of “low” flag results. This has the potential to decrease unnecessary follow-up, including repeat testing and further diagnostic procedures such as ACTH stimulation testing. Implementation of pediatric RIs has potential benefits regarding stress and cost for patients and parents, alarm fatigue for physicians, and utilization of laboratory resources.

Abstract Background Measuring the concentration of albumin, amylase, bilirubin, cholesterol, creatinine, glucose, lactate dehydrogenase (LDH), lipase, total protein(TP), triglycerides, and urea nitrogen(UN) in body fluids(BFs) provides important information to aid in clinical decision-making. The range of expected values of these analytes in BFs may not match serum, and the distribution by fluid type is not well described. Quality control (QC) materials are designed to reflect clinically relevant concentrations in blood. Hence, the measuring ranges for assays modified for BF testing vary in suitability. Laboratorians and manufacturers would benefit from understanding the overlap in BF and serum analyte concentrations. The aim of this study was to characterize the range of BF analyte concentrations compared to serum and assess the suitability of QC materials used on these assays. Methods A retrospective analysis was performed for the following analytes in BFs with reportable ranges(including maximum dilution factor): albumin = 0.2–12.0 g/dL(×2), amylase = 3–14 000 U/L(×100), bilirubin = 0.1–72.2 mg/dL(×2), cholesterol = 4–8000 mg/dL(×10), creatinine = 0.1–92.0 mg/dL(×4), glucose = 2–3375 mg/dL(×5), LDH = 10–9000 U/L(×10), lipase = 3–300 000 U/L(×1000), TP = 0.2–36.0 g/dL(×3), triglycerides = 4–8850 mg/dL(×10), and UN = 2–300 mg/dL(×3). Chemistry tests were run on a cobas® 6000 c501 (Roche Diagnostics,Indiana). Patient analyte concentration and fluid type results reported between 9/16/2019 and 1/27/2022 at all Mayo Clinic locations were extracted from an institutional database of electronic medical record data. Serum results were included for comparison. Descriptive statistical analyses (median and range) were performed with R (version 4.2.2)/R Studio(version 2022.12.0). QC materials for BF testing were purchased from Bio-Rad (Multilevel Qual, Levels 1 and 3; Hercules, CA, USA). Target concentrations are reported. Results Conclusion BF median (range) concentrations are similar or higher for bilirubin, creatinine, glucose, lipase, and UN. Serum QC material is likely appropriate for these assays in BFs. BF median(range) concentrations are lower for albumin, cholesterol, TP, and triglycerides suggesting that serum QC material may not be well suited for BFs. The need for extended dilutions may impact BF amylase and lipase.

Abstract Background Hemolysis is a pre-analytic issue that challenges clinical laboratories. When a specimen with significant hemolysis is obtained in our laboratory, tests where the hemolysis threshold is exceeded are not reported and blood is recollected. Unfortunately, in a subset of patients, the recollected specimen is also hemolyzed (termed “recurrent hemolysis”). In these cases, the second recollection utilizes special collection and handling protocols (i.e., hand-carried to lab, plasma collection, etc.) to mitigate preventable causes of hemolysis. Lipemia is also a known contributor to specimen hemolysis. Mayo Clinic Rochester experienced an increased rate of hemolysis as well as recurrent hemolysis during the height of the COVID-19 pandemic (January 2022). The objective of this study was to investigate the increased rate of recurrent hemolysis and compare to a rate prior to the COVID-19 pandemic (January 2019). Methods Retrospective data analysis was performed for January 2019 (negative control) and January 2022. The number of Mayo Clinic Rochester hospital admissions, admitting diagnosis, medications administered, and number of test collections performed were obtained using reporting functionality in our Electronic Health Record (EHR), Epic. The Laboratory Information System, SoftLab, was utilized to obtain recollection rates due to hemolysis. Data were normalized to total patient admissions for the specified period to account for inter-year variability. R/R Studio was utilized to analyze and visualize the data. Pearson’s Chi-squared test for independence was performed on categorical variables (significance defined as P < 0.05). Results A 28% decrease in hospital admissions (n = 3958:Jan-22 vs n = 5517:Jan-19) and a 23% decrease in total specimens collected on hospitalized patients (n = 40 557:Jan-22 vs n = 52 373:Jan-19) was observed between Jan-19 to Jan-22. However, the laboratory observed a 6% increase in hemolyzed specimens (n = 256:Jan-22 vs n = 241:Jan-19). Recurrent hemolysis occurred in 24% (n = 62/256) of Jan-22 and 17% (n = 43/241) of Jan-19 hemolyzed specimens and required special handling protocols. COVID positive patients comprised 48% (n = 30/62) of those requiring special handling protocols in Jan-22. Further examination revealed 34% (n = 21/62) of Jan-22 and 12% (n = 5/43) of Jan-19 cases of recurrent hemolysis were due to lipemia (P < 0.01). Chart review highlighted a potential source of lipemia from the administration of propofol, a lipophilic sedative emulsion. Of those COVID positive cases with recurrent hemolysis due to lipemia (n = 15/30), 93% (n = 14/15) were receiving propofol at the time of collection (P < 0.001). Conclusion We observed increased rates of specimen hemolysis during the COVID-19 pandemic. While most hemolysis resolves upon specimen recollection, patients with recurrently hemolyzed specimens often require special specimen collection and handling protocols to mitigate hemolysis. Approximately half of the recurrent hemolysis cases in Jan 2022 were COVID-19 positive patients. Lipemia-induced hemolysis was also more frequent in this patient population presumably due to the administration of propofol, a lipophilic emulsion sedative commonly used for COVID positive patients requiring sedation and ICU-level care. It is critical to understand the variety of factors which may contribute to recurrent hemolysis, as intervening with specialized collection and handling protocols to reduce observed pre-analytical hemolysis is required to provide accurate and timely laboratory results.

Background Hereditary and acquired thrombophilia are risk factors for venous thromboembolism (VTE). Whether testing helps guide management decisions is controversial. Objective These evidence-based guidelines from the American Society of Hematology (ASH) intend to support decision making about thrombophilia testing. Methods ASH formed a multidisciplinary guideline panel covering clinical and methodological expertise and minimizing bias from conflicts of interest. The McMaster University GRADE Centre provided logistical support, performed systematic reviews, and created evidence profiles and evidence-to-decision tables. The Grading of Recommendations Assessment, Development, and Evaluation approach (GRADE) was used. Recommendations were subject to public comment. Results The panel agreed on 23 recommendations regarding thrombophilia testing and associated management. Nearly all recommendations are based on very low certainty in the evidence due to modeling assumptions. Conclusions The panel issued a strong recommendation against testing the general population before starting combined oral contraceptives (COCs) and conditional recommendations for thrombophilia testing in the following scenarios: (a) patients with VTE associated with nonsurgical major transient or hormonal risk factors; (b) patients with cerebral or splanchnic venous thrombosis, in settings where anticoagulation would otherwise be discontinued; (c) individuals with a family history of antithrombin, protein C, or protein S deficiency when considering thromboprophylaxis for minor provoking risk factors and for guidance to avoid COCs/hormone replacement therapy; (d) pregnant women with a family history of high-risk thrombophilia types; and (e) patients with cancer at low or intermediate risk of thrombosis and with a family history of VTE. For all other questions, the panel provided conditional recommendations against testing for thrombophilia.

Objectives: Lung cancer is an important cause of mortality in the United States. Targeted mutation analysis has the potential to alter mortality in those with non-small-cell lung cancer. As such, the importance of timely tissue turnaround time (TAT) is substantial. We evaluated TAT at Mayo Clinic Arizona and found it to be delayed relative to national standards. Material and Methods: We conducted a series of plan, do, study, and act (PDSA) cycles at a single institution to identify areas for improvement with our lung cancer genomic testing. We assembled a multidisciplinary team and held serial meetings to discuss data from each PDSA cycle. Results: Using PDSA cycles and multidisciplinary discussions, we were able to identify a number of process limitations slowing TAT. We were then able to generate enhanced and timely communication between providers and pathology, educate and enforce the order/requisition workflow, and establish pathology accessioning with lung cancer specimens top priority. Conclusion: We were able to generate and implement a standard operating procedure for genomic testing of lung cancer specimens at our institution, thereby reducing tissue TAT.