Siemens ADVIA Centaur XP Research Articles

A mathematical algorithm to harmonize measurements for thyroid-stimulating hormone between instruments

BackgroundThyroid-stimulating hormone (TSH) is measured differently between diagnostic units using different devices, which makes cross-comparisons challenging. Here, we have developed a mathematical algorithm to harmonize TSH measurements between 2 instruments, the Abbott ISR2000 and the Siemens ADVIA Centaur XP. MethodsApplying the principle of the maximum allowable error between the standard curve and real signal values, the minimum number of comparison samples required for TSH hormone detection was calculated for both instruments. Next, a mathematical algorithm describing the relationship between TSH standard curves from both instruments was established. The algorithm was then tested on sample measurements from both instruments, with signals transformed to Siemens ADVIA Centuar XP-type data. Finally, test results were assessed where the relative error was <half of the total allowable error (1/2 TEa). ResultsBefore conversion, the mean percentage error between the TSH results of samples measured on both instruments was 23.20% (>1/2 TEa). After algorithmic transformation, the average percentage error was reduced to 7.93% (<1/2 TEa). ConclusionsOur algorithm enables TSH measurements across different instruments to be comparable, and provides a method to harmonize TSH data between laboratories that utilize different instrumentation.

Higher Than Recommended Folic Acid Intakes is Associated with High Folate Status Throughout Pregnancy in a Prospective French-Canadian Cohort

BackgroundFolate and vitamin B12 status during pregnancy are important for maternal and neonatal health. Maternal intake and prepregnancy body mass index (ppBMI) can influence biomarker status. ObjectivesThis study aimed to, throughout pregnancy; 1) assess folate and B12 status including serum total folate, plasma total vitamin B12, and homocysteine (tHcy); 2) examine how these biomarkers are associated with intakes of folate and B12 and with ppBMI; and 3) determine predictors of serum total folate and plasma total vitamin B12. MethodsIn each trimester (T1, T2, and T3), food and supplement intakes of 79 French-Canadian pregnant individuals were assessed by 3 dietary recalls (R24W) and a supplement use questionnaire. Fasting blood samples were collected. Serum total folate and plasma total vitamin B12 and tHcy were assessed by immunoassay (Siemens ADVIA Centaur XP). ResultsParticipants were 32.1 ± 3.7 y and had a mean ppBMI of 25.7 ± 5.8 kg/m2. Serum total folate concentrations were high (>45.3 nmol/L, T1: 75.4 ± 55.1, T2: 69.1 ± 44.8, T3: 72.1 ± 52.1, P = 0.48). Mean plasma total vitamin B12 concentrations were >220 pmol/L (T1: 428 ± 175, T2: 321 ± 116, T3: 336 ± 128, P < 0.0001). Mean tHcy concentrations were <11 μmol/L across trimesters. Most participants (79.6%–86.1%) had a total folic acid intake above the Tolerable Upper Intake Level (UL, >1000 μg/d). Supplement use accounted for 71.9%–76.1% and 35.3%–41.8% of total folic acid and vitamin B12 intakes, respectively. The ppBMI was not correlated with serum total folate (P > 0.1) but was weakly correlated with and predicted lower plasma total vitamin B12 in T3 (r = −0.23, P = 0.04; r2 = 0.08, standardized beta [sβ] = −0.24, P = 0.01). Higher folic acid intakes from supplements predicted higher serum total folate (T1: r2 = 0.05, sβ = 0.15, P = 0.04, T2: r2 = 0.28, sβ = 0.56, P = 0.01, T3: r2 = 0.19, sβ = 0.44, P < 0.0001). ConclusionsMost pregnant individuals had elevated serum total folate concentrations, reflecting total folic acid intakes above the UL driven by supplement use. Vitamin B12 concentrations were generally adequate and differed by ppBMI and pregnancy stage.

Indirect estimation of reference intervals for thyroid parameters using advia centaur XP analyzer.

BackgroundThe aim of this study was to determine the reference intervals (RIs) for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and FT3/FT4 ratio using indirect methods.MethodsWe analyzed 1256 results TSH, FT4 and FT3 collected from a laboratory information system between 2017 and 2021. All measurements were performed on a Siemens ADVIA Centaur XP analyzer using the chemiluminescent immunoassay. We calculated the values of the 2.5th and 97.5th percentiles as recommended by the IFCC (CLSI C28-A3).ResultsThe RIs derived for TSH, FT4, FT3 and FT3/FT4 ratio were 0.34-4.10 mIU/L, 11.3-20.6 pmol/L, 3.5-6.32 pmol/L and 0.21-0.47, respectively. We found a significant difference between calculated RIs for the TSH and FT4 and those recommended by the manufacturer. Also, FT3 values were significantly higher in the group younger than 30 years relative to the fourth decade (5.26 vs. 5.02, p=0.005), the fifth decade (5.26 vs. 4.94, p=0.001), the sixth decade (5.26 vs. 4.87, p<0.001), the seventh decade (5.26 vs. 4.79, p<0.001) and the group older than 70 years old (5.26 vs. 4.55, p<0.001). Likewise, we found for TSH values and FT3/FT4 ratio a significant difference (p <0.001) between different age groups.ConclusionsThe establishing RIs for the population of the Republic of Srpska were significantly differed from the recommended RIs by the manufacturer for TSH and FT4. Our results encourage other laboratories to develop their own RIs for thyroid parameters by applying CLSI recommendations.

The influence of RS738409 I148M polymorphism of patatin-like phospholipase domain containing 3 gene on the susceptibility of non-alcoholic fatty liver disease

We aimed to elucidate the frequency of polymorphic genotypes and alleles of patatin-like phospholipase domain containing 3 rs738409 polymorphism and its possible associations with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis in a cohort from Turkey.We enrolled 200 patients diagnosed with NAFLD and genotyped for rs738409 I148M polymorphism by real-time polymerase chain reaction, particularly by melting curve analysis. SPSS analysis software was used for statistical significance. Continuous variable values were expressed as mean ± standard deviation. Significant statistical level was chosen as p = 0.05.Our results demonstrate in a cohort from Turkey that rs738409 C > G polymorphism (I148M) of patatin-like phospholipase domain containing 3 gene is significantly able to affect individuals to have NAFLD in unadjusted regression model.Consistent with the previous studies in other populations, our study group showed a significantly higher risk of having NAFLD in unadjusted regression model but not in the adjusted model indicating that non-genetic factors such as age and sex may be responsible for the association. However, independent studies need to validate our findings with a larger group of NAFLD patients, as well as in different ethnic cohorts.

Role of C-reactive protein, serum ferritin, albumin, and lactate dehydrogenase in hospitalized coronavirus disease-19 infected patients - A study in tertiary care coronavirus disease-19 center in Eastern India

Background: Acute phase reactants such as C-reactive protein (CRP) and serum ferritin are elevated in acute inflammatory conditions and albumin acts a negative acute phase reactant. Studies have also shown that CRP, serum ferritin, and lactate dehydrogenase (LDH) levels are increased and albumin level decreased in coronavirus disease (COVID-19) patients. Aim and Objectives: The aim of the study was to know whether there is any change in CRP, serum ferritin, and albumin and LDH level in moderate-to-severe hospitalized COVID patients. Materials and Methods: The study population consisted of 50 adult symptomatic hospitalized COVID-19 infected patients 18 years of age or older diagnosed by Reverse transcriptase-polymerase chain reaction. Patients already diagnosed with anemia, thalassemia, and liver disease and receiving treatment were excluded from the study. CRP, LDH, and parameters of Liver function test were measured by commercial kits in fully automated Biochemistry Analyzer (ERBA XL 640). Ferritin analysis was performed by Siemens Advia Centaur XP (CLIA method). Results: Mean value for CRP, albumin, LDH, and ferritin was 47.43 ± 40.51 mg/L, 3.21± 0.68g/dl, 1281.86 ± 799.95 U/L, and 683.89 ± 503.21 ng/ml, respectively. Conclusion: CRP and serum ferritin along with LDH are markedly raised and albumin is decreased in moderate to severe COVID infected patients.

Reference Intervals for Thyroid-Associated Hormones and the Prevalence of Thyroid Diseases in the Chinese Population.

BackgroundThyroid diseases are highly prevalent worldwide, but their diagnosis remains a challenge. We established reference intervals (RIs) for thyroid-associated hormones and evaluated the prevalence of thyroid diseases in China.MethodsAfter excluding outliers based on the results of ultrasound screening, thyroid antibody tests, and the Tukey method, the medical records of 20,303 euthyroid adults, who visited the Department of Health Care at Peking Union Medical College Hospital from January 2014 to December 2018, were analyzed. Thyroid-associated hormones were measured by the Siemens Advia Centaur XP analyzer. The RIs for thyroid-associated hormones were calculated according to the CLSI C28-A3 guidelines, and were compared with the RIs provided by Siemens. The prevalence of thyroid diseases over the five years was evaluated and compared using the chi-square test.ResultsThe RIs for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were 0.71–4.92 mIU/L, 12.2–20.1 pmol/L, 3.9–6.0 pmol/L, 65.6–135.1 nmol/L, and 1.2–2.2 nmol/L, respectively. The RIs of all hormones except TT4 differed significantly between males and females. The RIs of TSH increased with increasing age. The prevalence of overt hypothyroidism, overt hyperthyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism was 0.5% and 0.8%, 0.2% and 0.6%, 3.8% and 6.1%, and 3.3% and 4.7% in males and females, respectively, which differed from those provided by Siemens.ConclusionsSex-specific RIs were established for thyroid-associated hormones, and the prevalence of thyroid diseases was determined in the Chinese population.

Establishment of measurement threshold and comparison of results for detection of Treponema pallidum specific antibody by Siemens ADVIACentaur XP chemiluminescent immunoanalyzer

To investigate the detection threshold of Treponema pallidum specific antibody method by chemiluminescent immunoassay (CLIA) in Siemens ADVIA Centaur XP for Syphilis serological test, and compare with the results derived from CMIA, TP-WB and TPPA method. The result can serve as reference for the application of CLIA. In total 30 887 samples screened by Treponema pallidum specific antibody method were collected by Abbott architect i2000 CMIA from July 2018 to July 2019 in Yanda Hospital of Hebei Province. We selected 153 patients with the ratio of sample absorbance to critical value (S/CO) of 1-9 by CMIA screening of Treponema pallidum specific antibody as the research objects. The reverse sequence of syphilis serological detection was adopted, and TP-WB and TPPA were used as the confirmation methods respectively. MedCalc software was used to analyze the results of ROC curve, and the cut-off value was obtained. Chi square test was used to test the difference significance of counting data. The detection results of Treponema pallidum specific antibody in the same batch of serum samples were unequal by different methods. There was no significant difference between CLIA method and TPPA method, but significant difference between CLIA method with TP-WB method and CMIA method was found. TPPA test results and TP-WB test results were taken as gold standards, ROC curve analysis showed that the best diagnostic cutoff value of CLIA method was 4.01 and 16.06, respectively, and the area under the curve was 0.961 and 0.838. The suggested cutoff value of CLIA method is quite different when using different syphilis serological test methods as the gold standard, Therefore, when the S/CO value determined by CLIA is between 1.00 to 16.06, TP-WB method should be recommended as the first choice in laboratory serological test for recheck and confirmation to avoid clinical misdiagnosis.

Performance evaluation of Siemens Atellica enhanced estradiol assay.

Serum estradiol (E2) levels may be used in the diagnostic and/or monitoring of a broad variety of clinical conditions. The aims of this study were to evaluate the Siemens enhanced estradiol assay (eE2) on Atellica IM 1600 (Siemens Healthineers) and to perform a sample comparison with the Siemens ADVIA Centaur XP (Siemens Healthineers). Within-day and between-day coefficient of variation (CV) were determined using serum sample pools and quality control materials. Six serum samples with decreasing concentrations of E2 were used to assess the limit of quantification. Linearity was evaluated using two different serum samples. Accuracy was evaluated by measuring three certified reference materials. Passing-Bablok regression and Bland-Altman plot were used for comparing Atellica and Centaur XP in 119 serum samples ranging from 45 to 10,059pmol/L. Within-day and between-day imprecision was <6.6%. Accuracy was <6.0% for all values except for 114pmol/L (22%). The study of limit of quantification resulted in an interday imprecision <20%. High correlation between measured and expected estradiol dilution results was observed (R=0.99), with recoveries ranging from 77 to 93%. Comparison study showed good agreement and no significant bias. The study shows that Atellica eE2 assay presents acceptable imprecision and accuracy and correlates well with Centaur XP.

Seroprevalence of Toxoplasma gondii infection among women of childbearing age in an endemic region of Romania, 2016-2018.

Toxoplasmosis is an important worldwide zoonosis caused by the protozoan parasite Toxoplasma gondii. This parasitic infection is often asymptomatic in immunocompetent people. However, if the infection occurs in pregnant women, it can have serious consequences for the foetus. In this study, we evaluated the seroprevalence of T. gondii in women of childbearing age in Arad County, Western Romania. Serum samples from 2626 women were analysed using a Siemens ADVIA Centaur XP Immunoassay System. Toxoplasma gondii IgG antibodies were demonstrated in 1081 women (41%) and prevalence tended to increase with age, from 32% in women aged 15–19 years to 62% in women aged 40–45 years. There was a higher prevalence in rural areas (46%) than in urban areas (36%). This study provides new data on T. gondii seroprevalence in women of childbearing age from Western Romania.

Serum Level of Biotin Rather than the Daily Dosage Is the Main Determinant of Interference on Thyroid Function Assays

Introduction: Several case reports stress that high-dose biotin causes incorrect laboratory results. However, the extent of this interference in children is not systematically studied. Aim: To assess factors associated with biotin interference on thyroid function tests in subjects with biotinidase deficiency. Method: The study included 44 children who were treated with oral biotin (Group 1, median dose: 10 mg/day [25–75p; 10–10], age: 1.83 years [1.04–2.90]) and 30 healthy subjects (Group 2, age: 1.05 years [0.37–3.37]). Thyroid function tests were performed with two different assays, and streptavidin-coated particles were used in order to remove biotin from serum samples of cases with biotin interference. Results: The measurements were first performed with Beckman Coulter. In Group 1, remarkably high levels of fT3 and fT4 were found in 26 (59.1%) and 25 (56.8%) patients, respectively. Thyroid hormone functions were all normal in Group 2. Significantly higher serum biotin levels were detected in interference-positive children (p < 0.001). The serum biotin levels in Group 1 showed a strong positive correlation with fT3 (r = 0.867, p < 0.001) and fT4 levels (r = 0.905, p < 0.001). A serum biotin level of 80.35 µg/L was found to be the best cut-off value for predicting interference (sensitivity: 96.2% and specificity: 94.4%). When analyzed with Siemens Advia Centaur XP, all thyroid function tests were normal in both groups except in one patient (2.27%) with slightly elevated fT3 level in Group 1. Repeated tests with Beckman Coulter after neutralization of biotin with streptavidin magnetic particles in serum samples of the interference-positive cases revealed normal thyroid hormone levels. Conclusion: Interference is an important problem in thyroid function tests in nearly 60% of all children receiving biotin treatment for biotinidase deficiency. Serum levels of biotin rather than the dosage are the main determinant of interference, which can be eliminated by choosing appropriate laboratory methods.

Verification of Access GI Monitor (CA 19-9) Assay on Beckman Coulter Unicel DXI 800

Abstract CA 19-9 antigen has been identified in patients with colorectal, pancreatic, bile duct, hepatocellular, stomach, and esophageal cancers. Noncancerous conditions that may elevate CA 19-9 levels include cirrhosis, cholangitis, hepatitis, pancreatitis, and nonmalignant gastrointestinal diseases. CA 19-9 antigen levels may be used as an aid in monitoring response to therapy or disease progression in cancer patients. The objective of this study was to assess the analytical performance of the Access GI Monitor assay on Beckman Coulter UniCel DXI 800. CA 19-9 was quantitatively determined on the Beckman Coulter UniCel DXI 800 following CLSI guidelines. The performance was evaluated for linearity, sensitivity, reference range, and precision. The within-run and between-run precisions were assessed by analyzing QC material at low and high levels of concentrations. Accuracy was assessed by comparison with the previously established Siemens ADVIA Centaur XP. Antigen level values were classified as positive or negative based on the upper limit of the reference range to assess concordance between the two analyzers. The accuracy of each analyzer was also assessed by correlating the discordant antigen values with the patients’ clinical history. For the Beckman Coulter DXI assay, the analytic measurement range was determined to be linear between 0.8 and 2,000 U/mL with a slope of 1.018 and intercept of 4.13. The limit of blank was determined as 0.09 U/mL. The reference range was verified as 0 to 35 U/mL. The within-run CVs for CA 19-9 were 3.7% at both the low level of 23.54 U/mL and high level of 262.56 U/mL. The between-run CVs at low and high levels were 4.34% and 6.36%, respectively. A total of 327 patient samples were analyzed in the comparison of CA 19-9 levels on Beckman Coulter DXI and Siemens ADVIA Centaur XP. On Deming regression, the slope was 0.665 with an intercept of 136.4 and correlation coefficient of 0.8964; there was wide scatter between the two methods. The mean bias between the two analyzers was –291.1 (–22.8%). The correlation coefficient was 0.8931, and the bias was –770.7 (–26.1%) when both were positive. The correlation coefficient was 0.7949, and the bias was –0.8 (–6.1%) when both were negative. The agreement of the two methods was 91% (n = 298) and disagreement was 9% (n = 29). After clinical analysis of 18 discordant values, six data points correlated better with the Siemens Centaur XP and the remaining 12 correlated better with the Beckman Coulter DXI. Our data demonstrate that CA 19-9 on Beckman Coulter DXI has good linearity and precision. There is poor to fair correlation between the two methods. Agreement based on clinical classification of positive and negative results is good. The Beckman Coulter DXI correlates with the patient clinical history better than the Siemens Centaur XP when comparing discordant values between the analyzers.

Verification of Access OV Monitor (Cancer Antigen 125) Assay on Beckman Coulter Unicel DXI 800

Abstract CA 125 levels are increased in ovarian carcinoma and other benign and malignant conditions. Levels are used to monitor response to therapy and disease progression. The objective of this study was to assess the analytical performance of the Access OV Monitor assay on the Beckman Coulter DXI. CA 125 was quantitatively determined on Beckman Coulter DXI following CLSI guidelines. Performance was evaluated for linearity, sensitivity, reference range, and precision. Within-run and between-run precisions were assessed by analyzing QC material at low and high concentrations. Accuracy was assessed by comparing 147 consecutive values with the previously established Siemens ADVIA Centaur XP. Antigen levels were classified as positive or negative based on the upper limit of the reference range to assess concordance between the two analyzers. The analytic measurement range was linear between 0.5 and 5,000 U/mL with a slope of 0.983 and intercept of 0.46. The reference range was 0 to 35 U/mL. Within-run CVs were 3.4% and 3.5% at low (53.81 U/mL) and high (392.78 U/mL) levels, respectively. Between-run CVs were 3.46% and 3.0% at low and high levels, respectively. The comparison results showed slope was 1.319 with an intercept of 12.61 and correlation coefficient of 0.9868 (Deming regression). The mean bias was 57.36 (33.98%). The correlation coefficient was 0.9633 and 0.9833 when CA 125 was negative and positive, respectively. The bias was 3.51 (25.73%) and 142.12 (34.41%) when CA 125 was negative and positive, respectively. The agreement was 94% (n = 138) and disagreement was 6% (n = 9). In conclusion, CA 125 on Beckman Coulter DXI has good linearity and precision and shows positive bias. There is good correlation and agreement between the two methods. Clinicians can reliably use the assay but should consider the potential bias when interpreting values near the upper end of the reference range.

STUDY OF SERUM ELECTROLYTES IMBALANCES IN FEMALE THYROID PATIENTS AT AIIMS, PATNA: A HOSPITAL BASED COMPARATIVE STUDY.

Objectives: This present study was to compare the serum electrolytes (Na, K and Cl) imbalances in hypothyroidism, hyperthyroidism with euthyroidism female cases.&#x0D; Methods: A detail history, clinical examinations and relevant investigations were performed to all female thyroid cases. Thyroid hormones were estimated by chemiluminiscence method using Siemens Advia Centaur XP instrument. Electrolyte levels (Na+, k+ &amp; Cl-) were measured by ion selective electrode method using Eschweiler combi.&#x0D; Results: Data was analyzed with the help of SPSS (version 26) software. Paired samples statistics was used. Mean ± standard deviation and t value were calculated. P value was taken less than or equal to 0.05 (p ≤ 0.05) for significant differences.&#x0D; Conclusions: This present study concluded that electrolytes sodium, potassium and chloride levels were significantly reduced in hypothyroidism female cases compared to euthyroids female (controls). This suggests that hypothyroid patients should be regularly checked for serum electrolytes. Early detection and treatment can prevent the further complications related to the disorder and will be helpful during the management of thyroid patients.&#x0D; Key words: Hypothyroidism, hyperthyroidism, euthyroidism, electrolytes.

Effects of sex, age, sampling time, and season on thyroid-stimulating hormone concentrations: A retrospective study

BackgroundMeasuring thyroid-stimulating hormone (TSH) is essential for diagnosing and monitoring thyroid diseases. The aim of this study was to evaluate the effect of sex, age, sampling time and season on TSH in a large Chinese population and to determine which factor had the greatest impact on TSH measurement results. MethodsData were obtained from the laboratory information system from September 1, 2013 to August 31, 2016. A total of 80150 TSH measurements of outpatients were enrolled in this study. TSH was measured using a Siemens ADVIA Centaur XP automatic chemiluminescence immunoassay analyzer. Linear regression models were used to assess the association between log-transformed TSH concentrations and sex, age, sampling time and season. ResultsThe serum TSH concentrations in women were significantly higher than in men. In all subjects, serum TSH concentrations increased by 0.005 μIU/mL for each year of age. TSH concentrations showed circannual variation during the 3 consecutive years of data collection and decreased during the summer while increased during the winter. The serum TSH concentrations decreased from 7 a.m. to 1 p.m. while increased from 1 p.m. to 4 p.m. The same trend was observed in TSH concentrations for sampling time stratified by sex. Linear regression revealed that sampling time might be the major factor affecting serum TSH concentrations. ConclusionSex, age, season, and sampling time significantly affected serum TSH concentrations. Age-related alteration in serum TSH concentrations was observed in this study. Sampling time was the major factor affecting serum TSH concentrations.

High-sensitivity cardiac troponins I sandwich assay by immunomagnetic microparticle and quantum dots

ObjectiveHigh-sensitivity cardiac troponins I (hs-cTnI) has been endorsed as a standard biomarker for diagnosis of acute myocardial infarction (AMI) and can provide information for risk stratification. Our study aimed to develop a quantum-dot-labeled magnetic immunoassay for the hs-cTnI detection. MethodsWe developed a novel immunomagnetic microparticle and quantum dots-based sandwich assay (QM-cTnI) that employs digital recording of fluorescence. Immunomagnetic microparticle conjugated with two monoantibodies was used as capture antibody, and two biotinylated monoantibodies were used as detection antibody, then quantum dots conjugated streptavidin served as a fluorescence bioprobe and the signal was recorded by the luminescence spectrometer. ResultsHs-cTnI was quantifiable in serum within one hour in the QM-cTnI assay which has a detection limit of 0.047 ng/mL and the effective measuring range was 0–40 ng/mL. The intra-assay and interassay coefficients of variation were 8.56% and 8.92% at 0.2 ng/mL, 5.83% and 7.66% at 4 ng/mL, and 6.21% and 8.76% at 20 ng/mL, respectively. All of the recovery rates were within the range of 98.11–101.89% and the average recovery rate was 99.69%. This assay performed well compared with FDA-approved SIEMENS ADVIA Centaur XP immunoassay system by 104 patient serum samples (R2 = 0.9951). High-concentration interferents (bilirubin, triglycerides, and hemoglobin) did not influence the test results indicating good specificity of the MQ-cTnI assay. ConclusionOur results demonstrated that hs-cTnI sandwich assay with the immunomagnetic microparticle and quantum dots-based multi-mAb approach is a sensitive, accurate, and quantitative method for the detection of disease biomarkers.

A long way to go for the harmonization of four immunoassays for carcinoembryonic antigen

BackgroundCarcinoembryonic antigen (CEA) is one of the most widely used tumor markers worldwide. CEA immunoassays often yield different results. The objective of the present study was to investigate the current state of harmonization among CEA tests. MethodsA total of 94 individual serum samples were divided into 3 subsets and measured in triplicate using 4 assays, Abbott Architect i2000SR, Beckman Access DXI800, Roche Cobas e601, and Siemens Advia Centaur XP. The standards from each manufacturer and the 1st International Reference Preparation (IRP) 73/601 of the World Health Organization were measured as unknowns in parallel with the patient samples using the 4 assays. The results of an external quality assessment (EQA) scheme for CEA were also analyzed. ResultsA perfect correlation was not observed between any 2 assays, and the values obtained using the 4 assays were different for the detection of 94 individual patient serum samples. No consistency was detected in the CEA results evaluated by various assays for EQA samples, individual patient samples, the standards from each manufacturer, and the WHO IRP 73/601. ConclusionsHarmonization of the CEA results obtained using the 4 immunoassays has not yet been achieved.

Serum thyroid hormone reference intervals in the apparently healthy individuals of Zhengzhou area of China.

This study aimed to establish reference intervals for serum thyroid hormones [serum thyroid-stimulating hormone (TSH), triiodothyronine (TT3), thyroxine (TT4), free triiodothyronine (FT3), and free thyroxine (FT4)] in apparently healthy individuals living in Zhengzhou. According to the requirement for laboratory support for the diagnosis and monitoring of thyroid diseases in the National Academy of Clinical Biochemistry (NACB) laboratory medicine practice guidelines, a total of 211 apparently healthy individuals were enrolled (94 men, 117 women, 23-77 years old) from Zhengzhou for measurement of serum levels of TSH, TT3, TT4, FT3, and FT4 by using the Siemens ADVIA Centaur XP analyzer. All markers were analyzed across gender- and age-specific groups by using the t-test and ANOVA. The reference intervals of all markers were determined by P2.5-P97.5. We detected gender-associated statistical significances for TT3, TT4, FT3, and FT4 (t=3.299, 2.141, 5.868, 5.358; P<0.05), but not for TSH (t=-1.776, P>0.05). Correlation analysis showed that all markers were negatively correlated with age (P>0.05). The new reference intervals for TT3, TT4, FT3, FT4, and TSH were established: 0.76-1.38 ng/mL, 5.96-11.27 μg/dL, 3.88-5.59 pM, 11.69-18.84 pM, 0.89-5.93 μIU/mL, respectively. In conclusion, we added a new database of reference intervals of the serum thyroid hormones for the Chinese adult population.

Concordance, Variance, and Outliers in 4 Contemporary Cardiac Troponin Assays: Implications for Harmonization

Data to standardize and harmonize the differences between cardiac troponin assays are needed to support their universal status in diagnosis of myocardial infarction. We characterized the variation between methods, the comparability of the 99th-percentile cutoff thresholds, and the occurrence of outliers in 4 cardiac troponin assays. Cardiac troponin was measured in duplicate in 2358 patient samples on 4 platforms: Abbott Architect i2000SR, Beckman Coulter Access2, Roche Cobas e601, and Siemens ADVIA Centaur XP. The observed total variances between the 3 cardiac troponin I (cTnI) methods and between the cTnI and cardiac troponin T (cTnT) methods were larger than expected from the analytical imprecision (3.0%-3.7%). The between-method variations of 26% between cTnI assays and 127% between cTnI and cTnT assays were the dominant contributors to total variances. The misclassification of results according to the 99th percentile was 3%-4% between cTnI assays and 15%-17% between cTnI and cTnT. The Roche cTnT assay identified 49% more samples as positive than the Abbott cTnI. Outliers between methods were detected in 1 patient (0.06%) with Abbott, 8 (0.45%) with Beckman Coulter, 10 (0.56%) with Roche, and 3 (0.17%) with Siemens. The universal definition of myocardial infarction should not depend on the choice of analyte or analyzer, and the between- and within-method differences described here need to be considered in the application of cardiac troponin in this respect. The variation between methods that cannot be explained by analytical imprecision and the discordant classification of results according to the respective 99th percentiles should be addressed.

Outliers as a Cause of False Cardiac Troponin Results: Investigating the Robustness of 4 Contemporary Assays

It is important that cardiac troponin be measured accurately with a robust method to limit false results with potentially adverse clinical outcomes. In this study, we characterized the robustness of 4 analytical platforms by measuring the outlier rate between duplicate results. We measured cardiac troponin concurrently in duplicate with 4 analyzers on 2391 samples. The outliers were detected from the difference between duplicate results and by calculating a z value: z = (result 1 - result 2) ÷ √(SD1(est)² + SD2(est)²), with z > 3.48 identifying outliers with a probability of 0.0005. The outlier rates were as follows: Abbott Architect i2000SR STAT Troponin-I, 0.10% (0.01%-0.19%); Beckman Coulter Access2 Enhanced AccuTnI, 0.44% (0.25%-0.63%); Roche Cobas e601 TroponinT hs, 0.06% (0.00%-0.13%); and Siemens ADVIA Centaur XP TnI-Ultra, 0.10% (0.01%-0.19%). The occurrence of outliers was higher than statistically expected on all platforms except the Cobas e601 (χ² = 2.7; P = 0.10). A conservative approach with a constant 10% CV and z > 5.0 identified outliers with clear clinical impact and resulted in outlier rates of 0.11% (0.02%-0.20%) with the Architect i2000SR STAT Troponin-I, 0.36% (0.19%-0.53%) with the Access2 Enhanced AccuTnI, 0.02% (0.00%-0.06%) with the Cobas e601 TroponinT hs, and 0.06% (0.00%-0.13%) with the ADVIA Centaur XP TnI-Ultra. Outliers occurred on all analytical platforms, at different rates. Clinicians should be made aware by their laboratory colleagues of the existence of outliers and the rate at which they occur.