Reference intervals for high sensitivity cardiac troponin I and N-terminal pro-B-type natriuretic peptide in children and adolescents on the Siemens Atellica.

OBJECTIVES: The cardiac biomarkers high sensitivity cardiac troponin I (hs-cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) are utilised in paediatric healthcare for the diagnosis and prognostic assessment of many conditions including myocarditis, congenital heart disease, multisystem inflammatory syndrome in children (MIS-C) and heart failure. However, the standardised age-related reference intervals, 99th percentile cut-offs and clinical guidelines are not available, making the interpretation of these biomarkers challenging. This study aimed to generate normative data in a paediatric cohort for the Siemens Atellica® IM 1300 analyser. METHODS: Residual plasma samples were collected from children aged up to 17 years attending primary care and out-patient settings and with no apparent evidence of cardiac dysfunction, renal dysfunction or other confounders. Reference intervals were generated using the 2.5th-97.5th percentiles, and 99th percentile cut-offs determined according to CLSI EP28-A3c. RESULTS: Statistical analysis revealed that partitioning was not required for gender for either biomarker. The reference interval for hs-cTnI for children aged one month to 16 years (n=292, 146 females and 146 males) was <14 ng/L with a 99th percentile cut-off of 19 ng/L. The reference interval for NT-proBNP for children aged one month up to one year was <714 ng/L (n=14) and for children aged 1-16 years (n=339) was <295 ng/L. CONCLUSIONS: This is the first paediatric reference interval data generated on the Siemens Atellica® solution. These reference intervals and 99th percentiles will inform clinical decisions in the paediatric cardiology setting.

Evaluation of the Atellica COAG 360 coagulation analyzer in a specialized coagulation laboratory.

BACKGROUND: Diagnosis of bleeding disorders includes correct analysis of coagulation factors VIII, IX, XI, XII, XIII, II, V, VII, and X and von Willebrand antigen and activity. The aim of this study was to evaluate the analytical performance of the Atellica COAG 360 analyzer in a specialized coagulation laboratory with focus on specific coagulation parameters involved in the diagnosis of bleeding disorders. METHODS: Verification included assessment of precision, reference interval, and method comparison according to local guidelines. For FVIII (Chromogenix) and FIX (Rossix), extended verifications were performed with additional assessment of linearity, detection limit, and comparability to BCS-XP. RESULTS: The precision was below 5% (normal levels) and below 10% (abnormal levels) and either improved or similar when compared to expected target values from a BCS-XP. The locally established reference range agreed well (≥80% of measured values within manufacturer's assigned ranges) for most of the methods. The lower limit of quantification was calculated to below 0.01 IU/ml for FVIII chromogenic (Chromogenix) and FIX chromogenic (Rossix), both with acceptable linearity. Bland-Altman analyses revealed generally good agreement between Atellica COAG 360 and BCS-XP in the determination of coagulation parameters, and differences between the two instruments did not result in any diagnostic change. CONCLUSIONS: The results of the evaluation show that the Atellica COAG 360 analyzer performs as expected to target values and equivalent to BCS-XP for the diagnosis of bleeding disorders in a specialized coagulation laboratory providing service to a hemophilia treatment center (HTC).

Consistency analysis of the Sysmex UF-5000 and Atellica UAS 800 urine sedimentation analyzers.

OBJECTIVE: To evaluate the consistency between the results of Sysmex UF-5000 system and Atellica® UAS 800 Urine Sediment Analyzer. METHODS: A total of 636 random urine samples were collected from inpatients and outpatients from March to September 2021. Urine was collected for analysis by the Sysmex UF-5000, Atellica UAS 800 systems, and manual microscopic examination. The results of manual microscopy as the gold standard, the coincidence rate and false-negative rate of Sysmex UF-5000 and Atellica UAS 800 systems in the detection of red blood cells, white blood cells, and casts were calculated. RESULTS: The coincidence rates of red blood cells, white blood cells, and cast, crystals, and other sediment components for the Sysmex UF-5000 system were 85.37%, 87.89%, 91.67%, 88.36%, and 71.86%. The false-negative rates were 28.47%, 3.75%, 68.97%, 37.25%, and 30.63%. The coincidence rates of red blood cells, white blood cells, and cast, crystals, and other sediment components for the Atellica UAS 800 system were 85.06%, 90.25%, 59.12%, 91.67%, and 67.45% and the false-negative rates were 60.42%, 21.25%, 36.21%, 19.64%, and 35.80%. CONCLUSION: Two instruments are superior in the detection of red blood cells and white blood cells. The Atellica UAS 800 system with image review has a good coincidence rate in the identification of crystals and casts. The identification of various sediment components in urine by both instruments meets the laboratory requirements. Two instruments with different methodologies have their own characteristics, and we should reasonably use them according to the conditions of the laboratory.

Pediatric reference intervals for endocrine markers and fertility hormones in healthy children and adolescents on the Siemens Healthineers Atellica immunoassay system.

OBJECTIVES: Rapid development in childhood and adolescence combined with lack of immunoassay standardization necessitates the establishment of age-, sex-, and assay-specific reference intervals for immunochemical markers. This study established reference intervals for 11 immunoassays on the new Siemens Healthineers Atellica® IM Analyzer in the healthy CALIPER cohort. METHODS: A total of 600 healthy participants (birth to 18 years) were recruited from the community, and serum samples were collected with informed consent. After sample analysis, age- and sex-specific differences were assessed, and outliers were removed. Reference intervals were established using the robust method (40-<120 participants) or nonparametric method (≥120 participants). RESULTS: Of the 11 immunoassays studied, nine required age partitioning (i.e., dehydroepiandrosterone-sulfate, estradiol, ferritin, folate, follicle-stimulating hormone, luteinizing hormone, progesterone, testosterone, vitamin B12), and seven required sex partitioning. Free thyroxine and thyroid-stimulating hormone demonstrated no significant age- and/or sex-specific differences. CONCLUSIONS: Overall, the age- and sex-specific trends observed closely mirrored those previously reported by CALIPER on other platforms as well as other internationally recognized studies. However, established lower and upper limits demonstrated some discrepancies between published values from healthy cohorts on alternate analytical systems, highlighting differences between manufacturers and the need for platform-specific reference intervals for informed pediatric clinical decision-making.

Multi-site performance evaluation and Sigma metrics of 20 assays on the Atellica chemistry and immunoassay analyzers.

Background The Atellica Solution comprises chemistry (CH) and immunoassay (IM) analyzers. Recently, six early adopter clinical laboratories across Europe evaluated the analytical performance of 20 CH and IM assays. To measure analytical performance quality, Sigma metrics were calculated for individual-site and pooled-site results. Methods Precision, detection capability, linearity, and method comparison studies were performed according to Clinical Laboratory Standards Institute protocols. Global Sigma metrics across sites were calculated from pooled data at the medical decision level using total allowable error (TEa) goals from CLIA for CH assays, and TEa goals from RiliBÄK for IM assays; and, the equation: Sigma metrics=%TEa-%bias/%CV. A pooled %CV was calculated by combining the imprecision obtained from individual sites. Bias calculations were performed against the ADVIA Chemistry system or ADVIA Centaur system using Deming regression analysis (Passing-Bablok regression for electrolytes) on the pooled-site data. The 103 individual-site Sigma metric calculations used individual-site imprecision and pooled-bias. Results The limits of blank and detection results agreed with the manufacturer's claims. Most assays were linear across the assay range tested. Pooled Sigma metrics were good or better (>4 Sigma) for 18 of 20 assays; and, acceptable for urea nitrogen (3.1) and sodium (3.9), the latter values attributable to higher imprecision at one of five sites. Conclusions Sigma metrics for data generated across multiple real-world sites evaluating the Atellica Solution demonstrated good or better performance of greater than 4 Sigma for 18 of 20 assays tested. Overall, results verified the manufacturer's claims that methods were fit for use in clinical laboratories.

Performance evaluation the new automated Atellica Hema 580 hematology analyzer.

INTRODUCTION: The Atellica Hema (Siemens Healthineers, Tarrytown, NY, USA) is a new generation multi-parameter analyzer for full blood count, 6-part differential and reticulocyte testing by impedance variation and fluorescence flow cytometry. In this study, we verified the whole blood and limited body fluid modes of the Atellica Hema 580. METHODS: We evaluated precision, linearity, carry-over, throughput and performed a method comparison to assess the performance of the Atellica Hema 580. For comparison of the Atellica Hema 580 with the Sysmex XN-1000 (Sysmex, Kobe, Japan), 140 samples from adult and pediatric patients including both normal and abnormal hematology profiles were analyzed in parallel. RESULTS: The Atellica Hema 580 demonstrated acceptable imprecision within the manufacturer's specifications for whole blood and body fluid modes, good linearity for high and low ranges and no significant carryover. The full blood count, differential and reticulocyte correlated well with the Sysmex XN-1000, except for mean cell hemoglobin concentration, basophil and large immature cells. The optical platelet count, reflexed in 34 samples with a platelet count <150 × 109 /l, showed a strong correlation with the fluorescent platelet count on the Sysmex XN-1000. The morphology flagging efficiency was 92% for white blood cells, 95% for red blood cells and 87% for platelets. CONCLUSION: The Atellica Hema 580 showed good analytical performance and workflow efficiency for a wide range of patient samples.

Double trouble: Unmasking two hook effects on Siemens Atellica® - Total PSA and total hCG assays.

The "hook effect" or "prozone phenomenon" occurs when the concentration of a particular analyte saturates the antibodies used in the test, resulting in falsely low or negative results despite the presence of high analyte concentrations. We report two recent cases of hook effect encountered with a widely used immunoassay analyzer, the Siemens Atellica® IM1600. The first case involves a patient with advanced metastatic prostate cancer whose total PSA (tPSA) concentration dropped dramatically from his last biological control. The second case concerns a pregnant woman whose total HCG (ThCG) levels were also subject to the hook effect and who was found to have a molar pregnancy. In both cases, a dilution step enabled to overcome this analytical concern and to obtain a correct result. In addition, a comparison of the sensitivity of different immunoassay analyzers to this phenomenon was carried out. To avoid this analytical error, an additional dilution step should automatically be performed when there is a clinical suspicion of elevated levels of tumor or hormone markers. Finally, the most affected manufacturers should adapt their assays, accordingly.

Insights into insulin analog cross-reactivity: a comparative study of Siemens Atellica and LC-MS/MS.

BACKGROUND: To address the challenges posed by inconsistent detection of analog insulin in commercially available insulin immunoassays, resulting in potential discrepancies in clinical findings and misdiagnosis during the investigation of factitious hypoglycemia., we aimed to evaluate the ability of the Siemens Atellica automated immunoassay to detect insulin analogs compared with LC-MS/MS. METHODS: Five insulin analogs were analyzed at 10 ng/mL spiked into serum samples, with recombinant human insulin as positive controls. Insulin and C-peptide assays were performed using Siemens Atellica and LC-MS/MS. Recovery rates were calculated. RESULTS: Siemens Atellica immunoassay demonstrated robust cross-reactivity (92-121%) of insulin analogs. In contrast, glargine was detected by LC-MS/MS but other analogs were not observed (<10% recovery). CONCLUSION: Our results indicate that the insulin assay conducted on the Siemens Atellica platform could be used to diagnose factitious hypoglycemia by detecting the specific insulin analogs involved. The findings from our studies indicate the suitability of this method for clinical laboratory use in cases where factitious hypoglycemia is under consideration as a potential diagnosis. Clinicians should take these results into account when interpreting insulin measurements, particularly in instances where insulin analog overdose is suspected.

The diagnostic performances of the Atellica® 1500 automated urinalysis system for ruling out bacterial urinary tract infection.

Urinary tract infection (UTI) is one of the most common diseases occurring in both hospitalized and community subjects. Urine culture is the gold standard test for the diagnosis of UTI, but approximately 80% are negative. The aim of this study was to evaluate the performance of the automated urinalysis system Atellica® 1500 (Siemens Healthineers, Erlangen, Germany) as screening tool for ruling out UTI. A total of 5,490 urine specimens from outpatients, that had simultaneous requests for urinalysis and urine culture, were evaluated. Of the 5,490 samples, 833 (15.2 %) resulted positive for urine culture. Among UTI-related parameters, bacterial count was considered the most apt to be diagnostic of subjects affected by UTI. Using a cutoff value for bacteria count equal to 180 elements/µL, Atellica® 1500 detected bacteriuria with diagnostic sensitivity (Se) of 88.1 %, diagnostic specificity (Sp) of 82.1 %, and negative predictive value (NPV) of 95.2 %. Comparing our results with the literature's data, we observed that our Se and NPV were lower, while our Sp was higher. Our data showed that the Atellica® 1500 system detected bacteria with satisfactory analytical performance, but the results obtained do not make it a reliable tool for excluding UTI with urinalysis.

Testing the stability of internal quality controls stored in the automated Atellica Solution refrigerated storage module.

Objectives: Atellica Solution (AS) is a platform that incorporates immunoassay and chemistry modules. AS is fitted with a refrigerated storage module (RSM) for internal quality controls (QC). The objective of this study was to assess the maximum permissible storage time in AS for QCs. Methods: A total of 48 analytes were tested using QC materials: Liquid Assayed Multiqual (MQ), Liquichek Immunology (LI), Liquichek Lipids (LL), and Liquichek Urine Chemistry (UC). The percentage of variation between results (Xt%) was calculated as the difference between the mean value of the triplicate performed at every time point of the study (Xt) and the average of the triplicate performed in the baseline time (Xo). Stability was assessed based on the total change limit (TCL), which combines analytical and biological variation: TCL=±âˆš((1.65 * CVa)2 + (0.5 * CVb)2). Results: A total of 40 of the 48 analytes tested remained stable at the end of the study. In relation to MQ and UC QCs, 32 of the 39 analytes remained stable for the whole study period (15 days) except for alkaline phosphatase, aspartate aminotransferase, calcium, lactate dehydrogenase, and total bilirubin in MQ, and chlorine and glucose in UC. In LI and LL QCs, eight of the nine analytes were stable throughout the 20 days of the study, except transferrin in LI. Conclusions: The Atellica Solution refrigerated storage module is a reliable system for the storage of quality control materials.

Analytical performance comparing siemens whole blood point of care Atellica VTLi to the central laboratory plasma Atellica IM high-sensitivity cardiac troponin I assays.

INTRODUCTION: This study examined the analytical performance of a whole blood (WB) point of care (POC) hs-cTnI assay compared to a plasma central laboratory hs-cTnI assay in patients presenting with ischemic symptoms to a US emergency department. METHODS: Fresh WB specimens collected at 0 and 2 h from 1089 consecutive patients (2152 total from 1076 matched specimens) were analyzed for hs-cTnI using WB on POC Siemens Atellica VTLi assay and plasma on central laboratory Siemens Atellica IM assay. Concordances were determined based on concentrations ranging from < limit of detection (LoD), LoD to overall and sex specific 99th percentiles from both the IFCC manufacturer package inserts and Universal Sample Bank (USB) data, and > 99th percentiles. Method comparisons were calculated using Passing Bablok regression and Bland Altmann plots, and linear regression determined by Pearson correlation coefficient. RESULTS: Baseline concentration comparisons showed: POC VTLi < LoD 4-5 %, ≥ LoD 95 %; Atellica IM < LoD 5-7 %, and ≥ LoD 94-95 %. From the 2152 paired 0 and 2-hour samples, based on 99th percentiles, overall concordance was 91-92 % (kappa 0.72-0.77) and discordance 8 %. Passing Bablok regression analysis using 1924 specimens between LoD to 500 ng/L showed: slopes 0.469-0.490; y-intercepts 1.753-2.028; r values 0.631-0.817. Pearson correlation coefficient showed moderate to strong correlation strength, even with up to 53 % cTnI concentrations variance (Passing Bablok slopes) vs 27.0-40.1 % (Bland-Altmann plots). CONCLUSIONS: Up to 95 % of measured samples were > LoD for both the POC (Atellica VTLi) and central laboratory (Atellica IM) hs-cTnI assays. Moderate to strong concordance and correlation were observed between assays, despite up to 53 % variances in cTnI concentration.

Verification of point-of-care analysers for C-reactive protein, lipid studies and glycated haemoglobin.

Due to increased convenience and faster test results, interest in point-of-care testing (PoCT) has grown significantly. Though PoCT may improve the speed and convenience of testing, the devices need to be fit for their intended purpose. Our aim was to verify the performance of Roche cobas b 101 and Abbott Afinion 2 for C-reactive protein (CRP), lipid studies and glycated haemoglobin (HbA1c), and Siemens Atellica DCA for HbA1c. For all PoCT analysers and measurands, accuracy was assessed by method comparison with central laboratory analysers. Passing-Bablok linear regression was performed, and Bland-Altman plots were generated. The proportion of samples within the Royal College of Pathologists of Australasia Quality Assurance Programs Analytical Performance Specifications (RCPAQAP APS) was assessed. Within-run and between-day imprecision was assessed and compared with manufacturer claims and biological variation or clinical guidelines for desirable imprecision. For CRP, both evaluated PoCT analysers had all samples within the RCPAQAP APS and had optimal imprecision according to biological variation. For lipid studies, the Roche cobas b 101 had most samples within the RCPAQAP APS, with two of 22 cholesterol, one of 22 high-density-lipoprotein-cholesterol (HDL-C) and zero of 22 triglyceride comparisons outside the RCPAQAP APS. The Abbott Afinion 2 had a positive bias with all three measured parameters, although the effect was more limited in the calculated parameters cholesterol:HDL-C ratio, non-HDL-C and low-density-lipoprotein-cholesterol (LDL-C). For HbA1c, all analysers had acceptable imprecision for monitoring with coefficient of variation (CV) <3% and minimal bias at the treatment target (HbA1c 53 mmol/mol or 7.0%). However, significant biases were apparent at higher or lower HbA1c for all analysers. All evaluated analysers were fit for purpose for CRP and for serial monitoring of HbA1c, although bias in some analysers was present at extremes of HbA1c. For lipid studies, the Roche cobas b 101 had fewer results outside the RCPAQAP allowable limits, and better precision. The Abbott Afinion 2 had a positive bias on both the cholesterol and HDL-C, but there is limited clinical impact when calculating cholesterol:HDL-C, LDL-C and non-HDL-C.

Changing Immunochemistry Platforms: Thyroid Function Test Comparison and Reference Intervals Based on Clinical Needs.

BACKGROUND: Diagnosis of thyroid dysfunction relies on thyroid stimulating hormone (TSH), free thyroxine (FT4), and free tri-iodothyronine (FT3) tests against valid reference intervals (RIs). We changed the immunoassay platform from Abbott Architect to Siemens Atellica and aimed to establish Atellica RIs based on laboratory information system (LIS) patient data. METHODS: Atellica thyroid hormone immunoassays were verified against those of Architect. Real-life patient results were retrieved from LIS. A single result per patient dataset was used to establish the RIs by the indirect method. RESULTS: Atellica and Architect assays correlated well but Atellica showed a positive bias between 13% and 53%, the largest for FT4. Variations of the Atellica assays were ≤4%. The 95% Atellica RIs were 0.4-3.8 mU/L for TSH, 0.9-1.6 ng/dL for FT4, and 227-416 pg/dL for FT3. Considering the accumulating clinical experience with Atellica, the RIs for clinical use were adjusted as 0.5-4.0 mU/L, 0.9-1.8 ng/dL, and 169-409 pg/dL, respectively. CONCLUSIONS: We verified thyroid hormone RIs for Atellica by the indirect method for the first time. Our model proved reliable for selecting results of presumably healthy individuals from LIS data. Critical review of the RIs with local endocrinologists is essential.

Verification of Atellica 1500 and comparison with Iris urine analyser and urine culture.

INTRODUCTION: The aims of study were to assess: 1) performance specifications of Atellica 1500, 2) comparability of Atellica 1500 and Iris, 3) the accuracy of both analysers in their ability to detect bacteria. MATERIALS AND METHODS: Carryover, linearity, precision, reproducibility, and limit of blank (LoB) verification were evaluated for erythrocyte and leukocyte counts. ICSH 2014 protocol was used for estimation of carryover, CLSI EP15-A3 for precision, and CLSI EP17 for LoB verification. Comparison for quantitative parameters was evaluated by Bland-Altman plot and Passing-Bablok regression. Qualitative parameters were evaluated by Weighted kappa analysis. Sixty-five urine samples were randomly selected and sent for urine culture which was used as reference method to determine the accuracy of bacteria detection by analysers. RESULTS: Analytical specifications of Atellica 1500 were successfully verified. Total of 393 samples were used for qualitative comparison, while 269 for sediment urinalysis. Bland-Altman analysis showed statistically significant proportional bias for erythrocytes and leukocytes. Passing-Bablok analysis for leukocytes pointed to significant constant and minor proportional difference, while it was not performed for erythrocytes due to significant data deviation from linearity. Kappa analysis resulted in the strongest agreements for pH, ketones, glucose concentrations and leukocytes, while the poorest agreement for bacteria. The sensitivity and specificity of bacteria detection were: 91 (59-100)% and 76 (66-87)% for Atellica 1500 and 46 (17-77)% and 96 (87-100)% for Iris. CONCLUSION: There are large differences between Atellica 1500 and Iris analysers, due to which they are not comparable and can not be used interchangeably. While there was no difference in specificity of bacteria detection, Iris analyser had greater sensitivity.

Pediatric reference intervals for 32 routine biochemical markers using the siemens healthineers atellica® CH assays in healthy children and adolescents.

BACKGROUND: Pediatric reference intervals are essential for test interpretation. With development of newer analytical systems, de novo reference interval establishment is of necessary importance. In the current study, pediatric reference intervals were determined for 32 analytes using Siemens Healthineers Atellica® CH assays in the CALIPER cohort of healthy children and adolescents. METHODS: Approximately 600 healthy children and adolescents were recruited with informed consent and collected serum samples were analyzed on the Siemens Healthineers Atellica® CH platform. Assays studied included enzymes, proteins, lipids, electrolytes, and additional markers Reference intervals were established according to Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: Of the 32 parameters, 26 required age partitioning and 18 required sex partitioning. Reference value distributions included consistent increases, decreases, and dynamic variation across the age continuum. Chloride, LDL cholesterol, glucose, lipase, sodium, and triglyceride demonstrated no age or sex-specific differences. CONCLUSION: The current study expands the clinical utility of the CALIPER database to include 32 Siemens Atellica® chemistry assays. Reference value distributions for Siemens assays mirrored those observed on other comparable assays/systems with few exceptions (e.g. lipase, direct and total bilirubin). These finding support the robustness of previously derived reference intervals in the CALIPER cohort and other global cohorts.

Standardization of two SARS-CoV-2 serology assays to the WHO 20/136 human standard reference material.

WHO 20/136 is standard reference material for SARS-COV-2 serology assays. Standardization of serology assays that target the same antigen and class of immunoglobulin will enable comparison of results between studies that use various lab-developed and commercial assays around the world. Standardization of assays will help better define immune correlates of protection and possibly immune correlates of vaccine efficacy. Two automated SARS-COV-2 anti-S1 RBD immunoglobulin serology assays on the Atellica IM Analyzer were calibrated to WHO 20/136 Standard Reference Material which was assigned 1000 binding antibody units (BAU/mL). The anti-S1 RBD IgG assay (sCOVG) cut-off Index of 1.00 corresponded to WHO 45.1 BAU/mL, and the anti-S1 RBD Ig Total assay (COV2T) cut-off Index of 1.00 corresponded to WHO 6.70 BAU/mL.

Quantification of urinary albumin and -creatinine: A comparison study of two analytical methods and their impact on albumin to creatinine ratio.

OBJECTIVES: Assessment of albuminuria through albumin to creatinine ratio (ACR) is a widely used method to identify and monitor kidney damage. Significant interassay differences in urinary albumin quantification have been documented, which may affect ACR. This study was conducted to assess quantification of urinary albumin and urinary creatinine by two different analytical platforms, Cobas 6000 and Atellica CH 930, to examine the concordance of ACR stratification. METHOD: 60 urinary albumin and 60 urinary creatinine concentrations were analyzed by Cobas 6000 and Atellica CH 930 using immunoturbidimetric assays for urinary albumin quantification and enzymatic assays for urinary creatinine quantification. Analytical performance was evaluated using Passing Bablok regression, Bland Altman plots, desirable specifications for inaccuracy and imprecision, and Wilcoxon test. Clinical significance was assessed through total error allowance (TEa) and concordance of ACR categories through Cohen's Kappa coefficient. Imprecision was assessed using control material of two levels. RESULTS: Results were within desirable specifications for inaccuracy. Statistical differences were found (p < 0.05) for both analytes. TEa results were exchangeable for urinary creatinine, whereas no exchangeability was found for urinary albumin. Cohen's Kappa confirmed an almost perfect agreement of ACRs between the two methods (K = 0.87), testing 42 samples. Five of the 42 samples were stratified into different categories of ACR. Results from control material were within limits of acceptable imprecision (CV < 5%). CONCLUSIONS: The findings of the study suggest that while differences in urinary creatinine results are not clinically significant, differences in urinary albumin results are. Despite an almost perfect agreement between the ACR results from Cobas 6000 and Atellica CH 930, there is a risk of incorrectly understanding a patient's kidney disease progression.

Effect of Outlier Elimination on the 99th Percentile Upper Reference Limits of High-Sensitivity Cardiac Troponin I Assays Based on a Strictly Selected Healthy Reference Population.

BACKGROUND: We established high-sensitivity cardiac troponin I (hsTnI) 99th percentile upper reference limits (URLs) for the Centaur XPT High-Sensitivity Troponin I assay (Centaur hsTnI; Siemens, Erlangen, Germany) and Atellica IM High-Sensitivity Troponin I assay (Atellica hsTnI; Siemens) and assessed the effect of outlier elimination. METHODS: The reference population comprised 380 men and 387 women, satisfying the strict systematic reference population criteria. After reference population verification by the N-terminal pro-B-type natriuretic peptide (NT-proBNP) assay, 99th percentile URLs for Centaur hsTnI and Atellica hsTnI were calculated before and after outlier elimination. RESULTS: The 99th percentile URL for Centaur hsTnI was 60.4 (men, 74.7; women, 57.5) ng/L and that for Atellica hsTnI was 59.6 (men, 75.2; women, 55.1) ng/L. After the elimination of 61 (8.0%) outlier samples in Centaur hsTnI and 58 (7.6%) in Atellica hsTnI, the 99th percentile URLs were 13.5 ng/L (men, 15.3 ng/L; women, 11.9 ng/L) and 13.4 ng/L (men, 15.5 ng/L; women, 12.9 ng/L), respectively, significantly lower than those before outlier elimination. The CVs at the 99th percentile URLs were 5.2% and 3.5%, respectively. The measurable fractions among the reference population were 91.5% and 93.4%, respectively. Performance evaluation of Atellica B-type natriuretic peptide (BNP), Atellica NT-proBNP, Centaur hsTnI, and Atellica hsTnI showed outstanding results. CONCLUSIONS: The Korean hsTnI 99th percentile URLs calculated in this study were significantly lower after outlier elimination than before. Centaur hsTnI and Atellica hsTnI meet the "Guideline acceptable" and "Level 3 (second generation, high sensitivity)" requirements, satisfying international standards.