Comparison of hematopoietic progenitor cell collection using different inlet flow rates with the Fenwal Amicus.

PURPOSE: We have used a hematopoietic progenitor cell (HPC) algorithm (standard [STD]) that restricted the inlet flow rate to 65 mL/min for peripheral white blood cell count (PWBC) >35 × 109 /L (STD). In this study, we evaluated a technique that allows 85 mL/min, regardless of the PWBC count (high). For patients with PWBC >35 × 109 /L, a prospective, randomized comparison of the high flow rate vs the STD PWBC-based flow rate (65 mL/min) was performed, comparing CD34+ and lymphocyte yields, collection efficiencies (CE1), mononuclear cells (MNC), and granulocytes, red blood cell (RBC), and platelet content. METHODS: The Fenwal Amicus version 4.5 with a heparinized ACD-A anticoagulant (AC) delivered at a 26:1 AC ratio was used. Paired comparisons between high and STD techniques were assessed with Wilcoxon signed rank tests, with P < .05 considered significant. Data are summarized as medians. RESULTS: Forty patient pairs (autologous) were compared. Diagnoses included primarily multiple myeloma (60%) and lymphoma (37.5%). High had significantly higher median average inlet rates (69 vs 55 mL/min), whole blood processed (20 vs 16 L), and cycles (15 vs 14) than STD. There were no significant differences in pre-procedure counts. Collection contents were (high/STD): 306/328 × 106 CD34+ cells, 48/59% CD34+ CE1 (significant), 0.2/0.2 × 109 /kg lymphocytes, 45/57% lymphocyte CE1, 63/59 × 109 WBC, 15/16 × 109 granulocytes, and 1.9/1.7 × 1011 platelets. CONCLUSIONS: The simpler, standardized high flow technique did not significantly increase or decrease CD34+ cells or lymphocyte yields, but did significantly decrease CD34+ CE1. The effects on cross-cellular content were minimal and not clinically significant.

Is It Time to Remove Total Calcium from the Basic and Comprehensive Metabolic Panels? Assessing the Effects of American Medical Association-Approved Chemical Test Panels on Laboratory Utilization.

BACKGROUND: The necessity of individual tests within the most commonly used disease-oriented test panels has not been well established. We evaluated test-ordering practices for total calcium, both before and after implementation of American Medical Association (AMA)-approved panels (basic metabolic panel [BMP] and comprehensive metabolic panel [CMP]) in our electronic ordering system. METHODS: We performed a retrospective review of all total calcium orders placed during April and June 2018, before and after implementation of the panels. Orders from inpatient, outpatient, and emergency department (ED) care units were totaled, and the percentage of abnormal test results was calculated. We then queried institutional databases to determine the number of unique patients with calcium-related diagnoses and compared the rates from a 5-month period both before and after implementation of the panels. RESULTS: Total test volumes and tests per unique patient increased by more than 3-fold after implementation of calcium-containing AMA-approved panels, with the majority of those orders coming from BMPs and CMPs. The rate of low calcium values increased because of the shift toward more inpatient testing; however, the percentage of abnormal results within each patient population (inpatient, outpatient, ED) decreased. The prevalence of hypo- and hypercalcemia-related diagnoses among patients in the 5 months after implementation did not change significantly (1.29% before implementation vs 1.27% after implementation). CONCLUSIONS: Implementation of BMPs and CMPs dramatically increased total calcium testing volumes without changing the rate of calcium-related diagnoses. The results suggest that the increase in total calcium orders associated with panel-based testing largely constitutes excess or unnecessary testing.

Autoimmune encephalitis epidemiology and a comparison to infectious encephalitis.

OBJECTIVE: To evaluate the incidence and prevalence of autoimmune encephalitis and compare it to that of infectious encephalitis. METHODS: We performed a population-based comparative study of the incidence and prevalence of autoimmune and infectious encephalitis in Olmsted County, Minnesota. Autoimmune encephalitis diagnosis and subgroups were defined by 2016 diagnostic criteria, and infectious encephalitis diagnosis required a confirmed infectious pathogen. Age- and sex-adjusted prevalence and incidence rates were calculated. Patients with encephalitis of uncertain etiology were excluded. RESULTS: The prevalence of autoimmune encephalitis on January 1, 2014 of 13.7/100,000 was not significantly different from that of all infectious encephalitides (11.6/100,000; p = 0.63) or the viral subcategory (8.3/100,000; p = 0.17). The incidence rates (1995-2015) of autoimmune and infectious encephalitis were 0.8/100,000 and 1.0/100,000 person-years, respectively (p = 0.58). The number of relapses or recurrent hospitalizations was higher for autoimmune than infectious encephalitis (p = 0.03). The incidence of autoimmune encephalitis increased over time from 0.4/100,000 person-years (1995-2005) to 1.2/100,000 person-years (2006-2015; p = 0.02), attributable to increased detection of autoantibody-positive cases. The incidence (2.8 vs 0.7/100,000 person-years, p = 0.01) and prevalence (38.3 vs 13.7/100,000, p = 0.04) of autoimmune encephalitis was higher among African Americans than Caucasians. The prevalence of specific neural autoantibodies was as follows: myelin oligodendrocyte glycoprotein, 1.9/100,000; glutamic acid decarboxylase 65, 1.9/100,000; unclassified neural autoantibody, 1.4/100,000; leucine-rich glioma-inactivated protein 1, 0.7/100,000; collapsin response-mediator protein 5, 0.7/100,000; N-methyl-D-aspartate receptor, 0.6/100,000; antineuronal nuclear antibody type 2, 0.6/100,000; and glial fibrillary acidic protein α, 0.6/100,000. INTERPRETATION: This study shows that the prevalence and incidence of autoimmune encephalitis are comparable to infectious encephalitis, and its detection is increasing over time. Ann Neurol 2018;83:166-177.

Plasma Ceramides.

Objective- Ceramides are sphingolipids involved with cellular signaling. Synthesis of ceramides occurs in all tissues. Ceramides accumulate within tissues and the blood plasma during metabolic dysfunction, dyslipidemia, and inflammation. Elevations of ceramides are predictive of cardiovascular mortality. We sought to verify the utility of plasma concentrations of 4 ceramides: N-palmitoyl-sphingosine [Cer(16:0)], N-stearoyl-sphingosine [Cer(18:0)], N-nervonoyl-sphingosine [Cer(24:1)], and N-lignoceroyl-sphingosine [Cer(24:0)] in predicting major adverse cardiovascular events in a diverse patient population referred for coronary angiography. Approach and Results- Plasma ceramides were measured in 495 participants before nonurgent coronary angiography. Coronary artery disease, defined as >50% stenosis in ≥1 coronary artery, was identified 265 (54%) cases. Ceramides were not significantly associated with coronary artery disease. Patients were followed for a combined primary end point of myocardial infarction, percutaneous intervention, coronary artery bypass, stroke, or death within 4 years. Ceramides were significantly predictive of outcomes after adjusting for age, sex, body mass index, hypertension, smoking, LDL (low-density lipoprotein) cholesterol, HDL (high-density lipoprotein) cholesterol, triglycerides, serum glucose, and family history of coronary artery disease. The fully adjusted per SD hazard ratios (95% confidence interval) were 1.50 (1.16-1.93) for Cer(16:0), 1.42 (1.11-1.83) for Cer(18:0), 1.43 (1.08-1.89) for Cer(24:1), and 1.58 (1.22-2.04) for the ceramide risk score. Conclusions- Elevated plasma concentrations of ceramides are independently associated with major adverse cardiovascular events in patients with and without coronary artery disease.

CSF free light chain identification of demyelinating disease: comparison with oligoclonal banding and other CSF indexes.

BACKGROUND: Cerebrospinal fluid (CSF) used in immunoglobulin gamma (IgG) index testing and oligoclonal bands (OCBs) are common laboratory tests used in the diagnosis of multiple sclerosis. The measurement of CSF free light chains (FLC) could pose as an alternative to the labor-intensive isoelectric-focusing (IEF) gels used for OCBs. METHODS: A total of 325 residual paired CSF and serum specimens were obtained after physician-ordered OCB IEF testing. CSF kappa (cKFLC) and lambda FLC (cLFLC), albumin and total IgG were measured. Calculations were performed based on combinations of analytes: CSF sum of kappa and lambda ([cKFLC+cLFLC]), kappa-index (K-index) ([cKFLC/sKFLC]/[CSF albumin/serum albumin]), kappa intrathecal fraction (KFLCIF) {([cKFLC/sKFLC]-[0.9358×CSF albumin/serum albumin]^[0.6687×sKFLC]/cKFLC)} and IgG-index ([CSF IgG/CSF albumin]/[serum IgG/serum albumin]). RESULTS: Patients were categorized as: demyelination (n=67), autoimmunity (n=53), non-inflammatory (n=50), inflammation (n=38), degeneration (n=28), peripheral neuropathy (n=24), infection (n=13), cancer (n=11), neuromyelitis optica (n=10) and others (n=31). cKFLC measurement used alone at a cutoff of 0.0611 mg/dL showed >90% agreement to OCBs, similar or better performance than all other calculations, reducing the number of analytes and variables. When cases of demyelinating disease were reviewed, cKFLC measurements showed 86% clinical sensitivity/77% specificity. CONCLUSIONS: cKFLC alone demonstrates comparable performance to OCBs along with increased sensitivity for demyelinating diseases. Replacing OCB with cKFLC would alleviate the need for serum and CSF IgG and albumin and calculated conversions. cKFLC can overcome challenges associated with performance, interpretation, and cost of traditional OCBs, reducing costs and maintaining sensitivity and specificity supporting MS diagnosis.

Diagnostic laboratory standardization and validation of platelet transmission electron microscopy.

Platelet transmission electron microscopy (PTEM) is considered the gold standard test for assessing distinct ultrastructural abnormalities in inherited platelet disorders (IPDs). Nevertheless, PTEM remains mainly a research tool due to the lack of standardized procedures, a validated dense granule (DG) count reference range, and standardized image interpretation criteria. The aim of this study was to standardize and validate PTEM as a clinical laboratory test. Based on previously established methods, we optimized and standardized preanalytical, analytical, and postanalytical procedures for both whole mount (WM) and thin section (TS) PTEM. Mean number of DG/platelet (plt), percentage of plts without DG, platelet count (PC), mean platelet volume (MPV), immature platelet fraction (IPF), and plt light transmission aggregometry analyses were measured on blood samples from 113 healthy donors. Quantile regression was used to estimate the reference range for DG/plt, and linear regression was used to assess the association of DG/plt with other plt measurements. All PTEM procedures were standardized using commercially available materials and reagents. DG interpretation criteria were established based on previous publications and expert consensus, and resulted in improved operator agreement. Mean DG/plt was stable for 2 days after blood sample collection. The median within patient coefficient of variation for mean DG/plt was 22.2%; the mean DG/plt reference range (mid-95th %) was 1.2-4.0. Mean DG/plt was associated with IPF (p = .01, R2 = 0.06) but not age, sex, PC, MPV, or plt maximum aggregation or primary slope of aggregation (p > .17, R2 < 0.02). Baseline ultrastructural features were established for TS-PTEM. PTEM was validated using samples from patients with previously established diagnoses of IPDs. Standardization and validation of PTEM procedures and interpretation, and establishment of the normal mean DG/plt reference range and PTEM baseline ultrastructural features, will facilitate implementation of PTEM as a valid clinical laboratory test for evaluating ultrastructural abnormalities in IPDs.

Paired comparison of therapeutic plasma exchange using the Fenwal Amicus versus TerumoBCT Spectra Optia.

PURPOSE: Terumo BCT Spectra Optia (O) and Fenwal Amicus (A) can perform therapeutic plasma exchange (TPE). We compared these systems in a prospective, randomized, crossover study of 81 paired procedures. Primary objective was to determine if there was a difference in platelet loss between the instruments. Secondary objectives were to determine differences in procedure time (PT), plasma removal efficiency (PRE 1), plasma removal rate (PRR), and fluid balance (FB). METHODS: Fifty-seven adults undergoing 162 procedures were included. Diagnoses included neurologic, nephrologic, and hematologic diseases. Replacement fluids included 5% normal serum albumin and/or fresh frozen plasma. The first instrument (randomized) established the inlet flow rate for the second with a maximum inlet rate of 120 ml/min. Spun HCT was used to program the procedure. One plasma volume was exchanged, for both instruments. Multivariable general estimating equations were used to assess the relationship between the outcome variables with machine after adjusting for covariates, with P values <.05 significant. RESULTS: Median total blood volume (4,775 mL-A, 4,775 mL-O) and preprocedure spun HCT (33%-A, 34%-O) were not statistically different. The plasma removed (3196 mL-A, 3120 mL-O), PLT in waste plasma (0.62 × 1011 -A, 0.33 × 1011 -O), PLT decline (8.5%-A, 6.5%-O), and PRR (48.1 mL/min-A, 49.2 mL/min-O) were not statistically different. There were statistically significant, but clinically irrelevant, differences in PLT CE1 (6.2%-A, 3.6%-O), PRE 1 (85.3%-A, 83.9%-O), FB (+2 mL-A,+15 mL-O), and PT (71 min-A, 71 min-O). CONCLUSIONS: Statistical differences were seen but none were of a magnitude to be clinically relevant, indicating comparable TPE performance.

Outcomes of plasma exchange in patients with transplant-associated thrombotic microangiopathy based on time of presentation since transplant.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare clinical syndrome associated with significant mortality. Although the use of plasma exchange (PE) in TA-TMA continues to be explored, evidence for its efficacy is debated. We performed a single institution, retrospective study to evaluate the efficacy of PE in treating TA-TMA patients. Special attention was given to efficacy in relation to the timing of presentation with TA-TMA since transplant. Thirty-three patients diagnosed with TA-TMA and treated with PE between January 1999 and December 2010 were included in the study. Clinical improvement was seen in eight patients (24%); four patients achieved complete resolution while the remaining four achieved partial resolution. All-cause day-30 and day-100 mortality was 33 and 55%, respectively. There was a trend toward a better outcome (complete/partial) for those presenting ≥ 100 days after transplantation (42%) vs. < 100 days after transplantation (14%; P-value = 0.15). Similarly, those presenting at ≥ 100 days had better, but not significantly, 30-day and 100-day all-cause mortality rates (17 and 33%, respectively) than those presenting at < 100 days (43 and 67%, respectively) (P-value = 0.25 and 0.08, for 30- and 100-day all-cause mortality, respectively). This is the first study looking at the efficacy of PE while considering the time of presentation since transplantation and is one of the largest single institution series of TA-TMA. The overall efficacy of PE is poor; however, patients who present with TA-TMA ≥100 days after transplant may have better outcome and lower mortality.

Defining a reference range for cold agglutinin titers.

BACKGROUND: The cold agglutinin (CAGG) titer is offered at our institution to aid in diagnosing cold agglutinin disease (CAD). Our goal was to create a seasonally adjusted reference range using prospective samples and compare it to a reference range generated retrospectively. STUDY DESIGN AND METHODS: Prospective CAGG titer testing was performed on healthy blood donors. Retrospective electronic analysis was performed on patients in two groups defined by current and historical testing methods. Blood donor testing was performed in January and July to determine if seasonal variation existed. Retrospective patients with conditions associated with CAD were excluded from analysis. Additional prospective CAGG testing using reference range program volunteers was performed to verify blood donor and patient result differences. RESULTS: Titers from the blood donor and patient cohorts had no age association (p > 0.44). Titers from those same cohorts did not show winter/summer variation (p > 0.11). No sex association was found with titer reference ranges in the blood donor and historical patient cohort. A sex association was found with titers in the current method patient cohort (male 64 to 512 and female ≤64; p < 0.0001). Blood donor CAGG titer lower 95% reference range was not more than 4 while historical and current patient cohorts ranges were not more than 32 and not more than 64, respectively. Reference range volunteers confirmed the narrow reference range in healthy individuals when compared to patients and blood donors. CONCLUSION: Prospective blood donor CAGG titers were lower than retrospective patient cohorts. This may be due to blood donors representing a healthier population than the patient cohorts.

Infusion technique of hematopoietic progenitor cells and related adverse events (CME).

BACKGROUND: The use of hematopoietic progenitor cell (HPC) transplant has risen over the past two decades. A variety of adverse events (AEs) of varying severity have been noted during HPC infusions. These AEs have been associated with several factors such as the amount of dimethyl sulfoxide and white blood cells in the HPC product. We performed a single-institution retrospective analysis to determine the effect of two different HPC infusion techniques, manual push with syringes versus infusion from bags with the aid of gravity, on the occurrence of infusion-related AEs. STUDY DESIGN AND METHODS: Infusions between December 2008 and November 2010 involving peripheral blood HPCs were reviewed. Pertinent clinical and HPC product-related information was recorded. Data were analyzed to determine the incidence of infusion-related AEs and its association with patient and product-related variables. RESULTS: We found 461 AEs in 645 patients during the study period. A total of 325 (50%) experienced at least one AE. Flushing was the most common type of AE followed by nausea and hypertension. The use of syringe infusion was more commonly associated with AEs (odds ratio, 1.82 [95% confidence interval, 1.32-2.50]; p=0.002). Other independent risk factors were cryopreserved products and the amount of polymorphonuclear leukocytes in the product. CONCLUSION: To our knowledge, this is the first study examining the effect of two different infusion techniques on infusion-related AEs. Our findings suggest that the use of bags for infusion protected the patients from AEs.

Failure of current laboratory protocols to detect lot-to-lot reagent differences: findings and possible solutions.

BACKGROUND: Maintaining consistency of results over time is a challenge in laboratory medicine. Lot-to-lot reagent changes are a major threat to consistency of results. METHODS: For the period October 2007 through July 2012, we reviewed lot validation data for each new lot of insulin-like growth factor 1 (IGF-1) reagents (Siemens Healthcare Diagnostics) at Mayo Clinic, Rochester, MN, and the University of Virginia, Charlottesville, VA. Analyses of discarded patient samples were used for comparison of lots. For the same period, we determined the distributions of reported patient results for each lot of reagents at the 2 institutions. RESULTS: Lot-to-lot validation studies identified no reagent lot as significantly different from the preceding lot. By contrast, significant lot-to-lot changes were seen in the means and medians of 105 668 reported patient IGF-I results during the period. The frequency of increased results increased nearly 2-fold to a high of 17%, without detectable changes in the underlying patient demographics. Retrospective statistical analysis indicated that lot-to-lot comparison protocols were underpowered and that validation studies for this assay required testing >100 samples to achieve 90% power to detect reagent lots that would significantly alter the distributions of patient results. CONCLUSIONS: The number of test samples required for adequate lot-to-lot validation protocols is high and may be prohibitively large, especially for low-volume or complex assays. Monitoring of the distributions of patient results has the potential to detect lot-to-lot inconsistencies relatively quickly. We recommend that manufacturers implement remote monitoring of patient results from analyzers in multiple institutions to allow rapid identification of between-lot result inconsistency.

Urinalysis is more specific and urinary neutrophil gelatinase-associated lipocalin is more sensitive for early detection of acute kidney injury.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) protein is a promising biomarker to detect acute kidney injury (AKI). Earlier detection of AKI could facilitate evaluation of novel therapeutic strategies. METHODS: Random and 24-h urine samples were prospectively obtained from 125 normal volunteers for analytic validation of a urinary enzyme-linked immunosorbent assay for NGAL. For clinical validation of the test, urine from 363 emergency department patients admitted to the hospital was obtained for NGAL enzyme-linked immunosorbent assay and urinalysis and AKI was determined by the use of Acute Kidney Injury Network (AKIN) criteria. RESULTS: NGAL was stable in urine for 7 days when ambient, 4 °C or frozen (-20 or -70 °C). The assay was linear between 0.24 and 10,000 ng/mL with a limit of quantitation of 0.24 ng/mL. Intra- and inter-assay precision were excellent (coefficient of variation <5%); however, urinary white blood cells were associated with increased NGAL levels. The 95th percentile reference value for NGAL in females is ≤ 65.0 and ≤ 23.4 ng/mL in males. Urinary NGAL levels increased with AKI stage but had only fair sensitivity (65%) and specificity (65%) to differentiate no AKI versus Stages 1, 2 or 3 (area under the curve 0.70). Urinalysis with microscopy was very specific (91%) but not very sensitive (22%) with an area under the curve of 0.57. CONCLUSIONS: NGAL can be reliably measured in clinical urine samples, although pyuria is an important potential confounder. In our cohort, increased urinary NGAL was associated with AKI by the AKIN criteria; however, the sensitivity and specificity were only fair, in part because patients with pre-renal causes are not excluded by AKIN criteria. Conversely, findings on microscopic urinalysis are very specific for AKI.

Single-center comparison of gel microcolumn and solid-phase methods for antibody screening.

Our facility changed antibody screening methods from a gel microcolumn-based test (ID-Micro Typing System Gel TEst; Ortho Clinical Diagnostics, Inc., Raritan, NJ) to an automated solid-phase test (Galileo/Capture-R Ready Screen [I and II], Immucor, Inc., Norcross, GA). To determine whether detection rates for commonly encountered clinically significant red blood cell antibodies differed as a consequence of this change, preimplementation and postimplementation antibody identification records were retrospectively reviewed. A statistically significant difference in the percentage of positive screening tests during the gel microcolumn testing period (73,903 total screens, 1.56% confirmed positive) versus the solid0-phase screening period (80,242 total screens, 1.81% confirmed positive; p< 0.0002) was observed . The number of antibodies to K identified was significantly lower with solid phase that with gel (27% decrease; p=0.004). It is unknown whether there is a statistical difference in delayed or hemolytic transfusion reaction rates as this was not evaluated.

Complement gene variant effect on relapse of complement-mediated thrombotic microangiopathy after eculizumab cessation.

Eculizumab is effective for complement-mediated thrombotic microangiopathy (CM-TMA), also known as atypical hemolytic uremic syndrome. Although lifelong therapy had been suggested, discontinuation does not universally lead to relapse. Comprehensive data evaluating risk factors for recurrence following discontinuation are limited. Our aim was to systematically review available literature assessing the role of complement genetic variants in this setting. Reports on CM-TMA and eculizumab withdrawal published before 1 January 2021, were included. Key reasons for patient exclusion were no follow-up after drug withdrawal and patients lacking complement genetic testing. Two-hundred eighty patients from 40 publications were included. Median age was 28 years, and 25 patients had a known history of renal transplant. Complement genetic variants were identified in 60%, most commonly in CFH (n = 59) and MCP/CD46 (n = 38). Of patients with a complement gene variant, 51.3% had ≥1 likely pathogenic/pathogenic variant whereas the remaining had variants of uncertain significance (VUS). Overall relapse rate after therapy discontinuation was 29.6%. Relapse rate was highest among patients with CFH variants and MCP/CD46 variants in canonical splice regions. VUS (P < .001) and likely pathogenic/pathogenic variants (P < .001) were associated with increased relapse. Presence of a renal allograft (P = .009); decreasing age (P = .029); and detection of variants in CFH (P < .001), MCP/CD46 (P < .001), or C3 (P < .001) were all independently associated with relapse after eculizumab discontinuation. Eculizumab discontinuation is appropriate in specific patients with CM-TMA. Caution should be exerted when attempting such a strategy in patients with high risk of recurrence, including a subgroup of patients with MCP/CD46 variants.

Late-night salivary cortisol for diagnosis of Cushing's syndrome by liquid chromatography/tandem mass spectrometry assay.

BACKGROUND: Late-night salivary cortisol (LNSC) measurements have been increasingly used by physicians as an initial diagnostic test for evaluation of patients with clinical suspicion of Cushing's syndrome (CS). Published studies include various numbers of cases, controls and importantly, various assay methods (vast majority various immunoassays), as well as various methods to generate cut-points. MATERIALS AND METHODS: The retrospective study evaluated the diagnostic utility of LNSC measurements in 249 patients evaluated for possibility of CS because of various clinical conditions using liquid chromatography/tandem mass spectrometry method (LC-MS/MS). CS was confirmed in 47 patients (18·9%) and excluded in 202 (81·1%) patients at the time of analysis. RESULTS: Late-night salivary cortisol was abnormal or >2·8 nmol/l in 35 of 47 patients with CS; sensitivity of 74·5% and elevated in 20 of 202 patients who were found not to have CS; specificity 90·1%. Using receiver-operator characteristic statistics for calculation of the most optimal sensitivity and specificity, the cut-off based on this data was LNSC > 2·1 nmol/l with sensitivity of 83·0% and specificity of 84·2%. CONCLUSION: Analysis of data at one referral institution showed somewhat limited sensitivity of LNSC for diagnosis of CS using current reference ranges.

CSF Kappa Free Light Chains: Cutoff Validation for Diagnosing Multiple Sclerosis.

OBJECTIVE: To determine and validate a cerebrospinal fluid (CSF) κ (KCSF) value statistically comparable to detection of CSF-specific oligoclonal bands (OCB) to support the diagnosis of multiple sclerosis (MS). PATIENTS AND METHODS: A total of 702 retrospective and 657 prospective paired CSF/serum samples from residual waste samples of physician-ordered OCB tests were obtained and tested for KCSF at Mayo Clinic. Charts were reviewed by a neurologist blinded to KCSF results. Specificity and sensitivity for MS diagnosis were evaluated to establish a diagnostic cutoff value for KCSF in the retrospective cohort and then validated in the prospective cohort. RESULTS: Retrospective and prospective subgroups, respectively, included MS (n=85, 70), non-MS (n=615, 585), and undetermined diagnosis (excluded, n=2, 2). The retrospective data established a KCSF cutoff value of 0.1 mg/dL to be comparable to OCB testing. In the retrospective subgroup, KCSF vs OCB sensitivities for diagnosis of MS were 68.2% vs 75.0% (P=.08) and specificities were 86.1% vs 87.6% (P=.27). The KCSF area under the receiver operating characteristic curve was 0.772 (95% CI, 0.720 to 0.824), and for OCB was 0.813 (95% CI, 0.764 to 0.861). The prospective cohort was then used to validate the diagnostic KCSF value of 0.1 mg/dL; KCSF vs OCB sensitivities were 78.6% for both (P>.99) and specificities were 87.1% vs 89.4% (P=.09). CONCLUSION: The KCSF value of 0.1 mg/dL is a valid alternative to OCB testing, offering a standardized quantitative measure, eliminating human error, reducing cost and turnaround time, with no significant difference in sensitivity and specificity. This study provides class I evidence that a KCSF value of 0.1 mg/dL can be used in place of OCB testing to support the diagnosis of MS.

Population-Based Epidemiology Study of Paraneoplastic Neurologic Syndromes.

OBJECTIVES: Population-based epidemiologic data for paraneoplastic neurologic syndromes (PNSs) in the United States are lacking. Our objective was to evaluate the incidence, prevalence, and associated morbidity of PNS. METHODS: We performed a population-based epidemiology study in Olmsted County, Minnesota, with patients identified between January 1, 1987, and December 31, 2018, using the medical records linkage system of the Rochester Epidemiology Project (REP) who met the definite/probable 2021 PNS criteria and 2004 PNS criteria. Patients with dermatomyositis and myasthenia gravis with underlying tumors were included. Age- and sex-specific population counts were obtained from REP resources for January 1, 2014 (prevalence denominator) and annually for 1987-2018 (incidence denominator). Morbidity was estimated using disability-adjusted life years (DALYs; years lived with disability [YLD] plus years of life lost [YLL]). RESULTS: There were 28 patients with PNS identified (50% female) residing in Olmsted County, Minnesota, with median age at diagnosis of 54.5 (IQR 46.5-69.0) years. All patients had a cancer diagnosis, and 18 (64%) patients were neural autoantibody positive including antineuronal nuclear autoantibody type 1 (ANNA-1/anti-Hu; n = 1), ANNA-2/anti-Ri (n = 1), muscle-type acetylcholine receptor (AChR; n = 6), Purkinje cell cytoplasmic antibody type 1 (PCA-1/anti-Yo; n = 1), kelch-like protein 11 (KLH11; n = 3), collapsin response mediator protein 5 (CRMP-5/anti-CV2; n = 2), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (n = 1), neurofilament light chain (n = 1), leucine zipper 4 (LUZP4; n = 1), and unclassified neural antibodies (n = 1). PNS incidence was 0.6/100,000 person-years and increased over time from 0.4/100,000 person-years (1987-2002) to 0.8/100,000 person-years (2003-2018) (p = 0.06). Prevalence was 5.4/100,000 people. The median follow-up period after PNS diagnosis was 3.1 years (IQR, 1.1-9.9 years). Total disability-adjusted life years (DALYs) for 28 patients with PNS were 472.7 years, based on total years of life lost (YLL) for patients dying between 1987 and 2018 (n = 15) of 445.3 years plus years lived with disability (YLD) 27.4 years. DISCUSSION: PNSs are rare neurologic disorders but are associated with severe morbidity and mortality. The estimated number of prevalent PNS cases in the United States is 17,099, and predicted DALY for all US PNS cases is 292,393 years. Their apparent increasing rate of detection is attributable to increasing physician awareness and availability of serologic testing.

Clinical validation of cutoff target ranges in newborn screening of metabolic disorders by tandem mass spectrometry: a worldwide collaborative project.

PURPOSE: To achieve clinical validation of cutoff values for newborn screening by tandem mass spectrometry through a worldwide collaborative effort. METHODS: Cumulative percentiles of amino acids and acylcarnitines in dried blood spots of approximately 25­30 million normal newborns and 10,742 deidentified true positive cases are compared to assign clinical significance, which is achieved when the median of a disorder range is, and usually markedly outside, either the 99th or the 1st percentile of the normal population. The cutoff target ranges of analytes and ratios are then defined as the interval between selected percentiles of the two populations. When overlaps occur, adjustments are made to maximize sensitivity and specificity taking all available factors into consideration. RESULTS: As of December 1, 2010, 130 sites in 45 countries have uploaded a total of 25,114 percentile data points, 565,232 analyte results of true positive cases with 64 conditions, and 5,341 cutoff values. The average rate of submission of true positive cases between December 1, 2008, and December 1, 2010, was 5.1 cases/day. This cumulative evidence generated 91 high and 23 low cutoff target ranges. The overall proportion of cutoff values within the respective target range was 42% (2,269/5,341). CONCLUSION: An unprecedented level of cooperation and collaboration has allowed the objective definition of cutoff target ranges for 114 markers to be applied to newborn screening of rare metabolic disorders.

Updated ferritin reference intervals for the Roche Elecsys® immunoassay.

Reference intervals (RI) for ferritin are the subject of some controversy, with indications that changes in lifestyle and demographics (e.g., obesity) have limited the validity of RIs established decades ago. Package insert RIs for the Roche Elecsys® immunoassay do not include expected values for pediatric (<17-20 years) or geriatric (>60 years) individuals; furthermore the female ranges were established in mostly premenopausal volunteers. To establish more robust RIs, we utilized 5 years of retrospective patient data from physician-ordered ferritin measurements and excluded results from patients with diagnoses known to affect ferritin concentrations. Ferritin results from 1438 unique patients aged 7 months to 91 years were included in the study. Continuous RIs were fitted for females (n = 951) and males (n = 487) as a function of age; these were then divided into clinically relevant sex-specific age breaks. RIs were established for pre-adolescent (<10 years), adolescent (10-17 years) and adult males, and for pediatric (<18 years), adult (18-50 years) and older (>50 years) females. Established RIs were verified using specimens obtained from healthy donors.

Using high sensitivity cardiac troponin values in patients with SARS-CoV-2 infection (COVID-19): The Padova experience.

BACKGROUND: The spectrum of Coronavirus Disease 2019 (COVID-19) is broad and thus early appropriate risk stratification can be helpful. Our objectives were to define the frequency of myocardial injury using high-sensitivity cardiac troponin I (hs-cTnI) and to understand how to use its prognostic abilities. METHODS: Retrospective study of patients with COVID-19 presenting to an Emergency Department (ED) in Italy in 2020. Hs-cTnI was sampled based on clinical judgment. Myocardial injury was defined as values above the sex-specific 99th percentile upper reference limits (URLs). Most data is from the initial hospital value. RESULTS: 426 unique patients were included. Hs-cTnI was measured in 313 (73.5%) patients; 85 (27.2%) had myocardial injury at baseline. Patients with myocardial injury had higher mortality during hospitalization (hazard ratio = 9 [95% confidence interval (CI) 4.55-17.79], p < 0.0001). Multivariable analysis including clinical and laboratory variables demonstrated an AUC of 0.942 with modest additional value of hs-cTnI. Myocardial injury was associated with mortality in patients with low APACHE II scores (<13) [OR (95% CI): 4.15 (1.40, 14.22), p = 0.014] but not in those with scores > 13 [OR (95% CI): 0.48 (0.08, 2.65), p = 0.40]. Initial hs-cTnI < 5 ng/L identified 33% of patients that were at low risk with 97.8% sensitivity (95% CI 88.7, 99.6) and 99.2% negative predictive value. Type 1 myocardial infarction (MI) and type 2 MI were infrequent. CONCLUSIONS: hs-cTnI at baseline is a significant predictor of mortality in COVID-19 patients. A value < 5 ng/L identified patients at low risk.