Total lab automation: sample stability of clinical chemistry parameters in an automated storage and retrieval module.

OBJECTIVES: Automated storage and retrieval modules (SRM), as part of total lab automation (TLA) systems, offer tremendous practical and economic benefits. In contrast to manual storage systems, SRMs indicate continuous motion of samples and may leave samples prone to temperature fluctuations. This study investigates analyte stability in serum and heparin plasma within an automated storage module. METHODS: The stability of 28 common biochemistry analytes was investigated using 57 freshly obtained routine serum samples and 42 lithium-heparin plasma samples. Following baseline measurement, samples were stored at 2-8 °C in the automated SRM of the Accelerator a3600 TLA and reanalyzed at fixed time points (2, 4, 8, 12, 24, 48 and 72 h) on the Abbott Architect c16000 chemistry analyzer. The concentration at each time point was expressed as %-difference to the baseline value and mean results were compared to the criteria for desirable bias derived from the biological variation database. RESULTS: Nine of the analytes exceeded the bias criterion within 72 h after initial measurement in either serum samples, plasma samples or both. Lithium-heparin plasma samples showed increasing values for phosphor, potassium and lactate dehydrogenase (LDH), which were only considered stable for respectively 24, 12 and 4 h, glucose was considered stable for 8 h. Electrolyte concentrations and LDH activity significantly increased in serum samples beyond 48 h. Bicarbonate should not be performed as add-on test at all. CONCLUSIONS: The presented data indicate that the conditions within an SRM have no clinical impact on sample stability and allow stable measurement of routine analytes within 72 h, comparable to manual storage facilities.

Evaluation of BD Vacutainer® Barricor™ blood collection tubes for routine chemistry testing on a Roche Cobas® 8000 Platform.

INTRODUCTION: Barricor™ Vacutainers® are a novel non-gel separator blood collection tube. These tubes enable faster pre-analytical processing which could reduce turnaround time and be beneficial in an acute care setting. We sought to evaluate the bias, stability, and integrity of plasma generated from these tubes compared to Plasma Separator Tubes™ (PST) for 50 routine chemistry analytes on a Roche Cobas® 8000 analyzer. METHODS: Paired samples were collected from 150 patients originating in the emergency department and outpatient collections at the Saint John Regional Hospital. Barricor™ vacutainers were centrifuged for 3 min at 4000g and PST™ vacutainers for 10 min at 1300 g within two hours of collection. Plasma samples (n = 126) were then analyzed for 50 chemistry analytes and bias determined between tubes. Ten-day stability of AST, glucose, potassium, phosphate, and LDH was also assessed in a subset of paired samples (n = 4). Lastly, the quality of plasma (n = 20) was assessed through measurement of cell counts on a DxH Hematology Analyzer. RESULTS: All 50 analytes demonstrated comparable results across a broad concentration range between Barricor™ and PST™ vacutainers (average percent bias -1.5% to 6.1%; Deming linear regression slopes 0.933-1.041; correlation coefficients ≥ 0.9144). AST, potassium, glucose and LDH were stable for 10 days in Barricor™ vacutainers (change from baseline < 10%) but <5 days in PST™ vacutainers while phosphate was stable for 4 days in Barricor™ vs 2 days in PST™ vacutainers. Platelet counts were statistically lower in Barricor™ compared to PST™ vacutainers. CONCLUSION: Our data suggest that Barricor™ vacutainers are an acceptable alternative to PST™ vacutainers while offering the added benefit of decreased pre-analytical processing time, increased stability of certain analytes, and possibly less cellular contamination.

Effects of two types of medical contrast media on routine chemistry results by three automated chemistry analyzers.

OBJECTIVES: The use of iodinated contrast media has grown in popularity in the past two decades, but relatively little attention has been paid to the possible interferential effects of contrast media on laboratory test results. Herein, we investigate medical contrast media interference with routine chemistry results obtained by three automated chemistry analyzers. METHODS: Ten levels of pooled serum were used in the study. Two types of medical contrast media [Iopamiro (iopamidol) and Omnipaque (iohexol)] were evaluated. To evaluate the dose-dependent effects of the contrast media, iopamidol and iohexol were spiked separately into aliquots of serum for final concentrations of 1.8%, 3.6%, 5.5%, 7.3%, and 9.1%. The 28 analytes included in the routine chemistry panel were measured by using Hitachi 7600, AU5800, and Cobas c702 analyzers. We calculated the delta percentage difference (DPD) between the samples and the control, and examined dose-dependent trends. RESULTS: When the mean DPD values were compared with the reference cut-off criteria, the only uniformly interferential effect observed for all analyzers was in total protein with iopamidol. Two additional analytes that showed trends toward interferential effects only in few analyzers and exceeded the limits of the allowable error were the serum iron and the total CO2. The other combinations of analyzer and contrast showed no consistent dose-dependent propensity for change in any analyte level. CONCLUSIONS: Our study suggests that many of the analytes included in routine chemistry results, except total protein and serum iron, are not significantly affected by iopamidol and iohexol. These results suggest that it would be beneficial to apply a flexible medical evaluation process for patients requiring both laboratory tests and imaging studies, minimizing the need for strict regulations for sequential tests.

The study of statistical methods for evaluating the comparability of routine chemistry analytes among 3 routine laboratory measurement systems in China.

BACKGROUND: Clinical laboratory tests are important for clinicians to make diagnostic decisions, but discrepancies may directly lead to incorrect diagnosis. We would like to introduce some statistical methods to evaluate the comparability of chemistry analytes while comparing the performances of different measurement systems. METHODS: We used a panel of 10 fresh-frozen single donation serum samples to assess assays for the measurement of glucose and other 13 analytes. Statistical methods used in this article include traditional statistical analysis, robust statistics, regression analysis and differences on medical decision levels (MDL). All the statistical analysis results would be evaluated. 20 Chinese tertiary hospitals accredited to ISO 15189 took part in this work. The commercial random access platforms included: Olympus (8 labs), Hitachi (6 labs) and Roche (6 labs). To compare the acceptable rates, Chi square test was used. RESULTS: The statistical analysis results are as follows: (1) Coefficient of variations are between 2.8 and 3.9 %, with the slopes and intercepts of regression functions between 0.928 to 1.064 and -0.174 to 0.630, respectively. (2) The percentage of robust z-scores between -2 and 2 is bigger than 90 %. (3) The total percentages of differences on all the MDLs are: less than optimal was 31.7 % (19/60); less than desirable was 60.0 % (36/60); less than minimum was 65.0 % (39/60); more than minimum was 35.0 % (21/60). In this study, 2 laboratories (Nos. 8 and 16) were considered as poor performance by z-scores. 10 laboratories (Nos. 4, 5, 7, 8, 9, 10, 11, 14, 16 and 19) have unacceptable measurement errors on MDLs. 10 laboratories (Nos. 1, 2, 3, 6, 12, 13, 15, 17, 18, 20) can achieve mutual recognition of serum glucose testing results, including: 5 (5/8) Olympus, 2 (2/6) Hitachi and 3 (3/6) Roche. There was no significant difference among acceptable rates of the three measurements systems for the serum glucose assay. CONCLUSIONS: Traditional statistical analysis, robust statistics and robust z-score, fitting linear regression equations and calculating differences on different MDLs can be used on studying the comparability and mutual recognition of clinical chemistry analytes among hospitals or laboratories in China. The mutual recognition and interchangeability of results remains jeopardized even among tertiary hospitals in China. More works and efforts should be done for improvement of the current situation of interchangeability of results in clinical laboratories in China.

Imprecision Investigation and Analysis of Routine Chemistry in China.

BACKGROUND: This study aims to investigate the imprecision of internal quality control of routine chemistry analytes so that we can have an overall knowledge of imprecision level of measurement in laboratories in China. METHODS: The internal quality control information including two kinds of coefficient of variations (CVs) of 22 analytes were collected via an on-line questionnaire. Then, the percentages of laboratories meeting the quality requirement for each analyte were calculated according to five imprecision criteria. RESULTS: Among these 22 analytes, creatine kinase got the most satisfied result, the percentages of laboratories whose current CV met 1/3 total allowable error (1/3TEa), 1/4TEa, and the specifications based on biological variation were 99.3%, 95.9%, 99.6%, 99.9%, and 90.6%, respectively, while Na got the lowest satisfaction rate according to these specifications, which were 4.15%, 22.4%, 4.2%, 9.0%, and 1.3%, respectively. From an overall perspective, most of the 22 analytes got a satisfied result when applying the criteria defined by CLIA'88, while only a small amount of laboratories can meet the requirement when applying the specifications derived from biological variation. CONCLUSIONS: There is huge space for us to enhance and substantial effort is needed in improving and implementing quality management in China.

CLSI-based transference of CALIPER pediatric reference intervals to Beckman Coulter AU biochemical assays.

OBJECTIVE: The CALIPER program has established a comprehensive database of pediatric reference intervals using largely the Abbott ARCHITECT biochemical assays. To expand clinical application of CALIPER reference standards, the present study is aimed at transferring CALIPER reference intervals from the Abbott ARCHITECT to Beckman Coulter AU assays. DESIGN AND METHODS: Transference of CALIPER reference intervals was performed based on the CLSI guidelines C28-A3 and EP9-A2. The new reference intervals were directly verified using up to 100 reference samples from the healthy CALIPER cohort. RESULTS: We found a strong correlation between Abbott ARCHITECT and Beckman Coulter AU biochemical assays, allowing the transference of the vast majority (94%; 30 out of 32 assays) of CALIPER reference intervals previously established using Abbott assays. Transferred reference intervals were, in general, similar to previously published CALIPER reference intervals, with some exceptions. Most of the transferred reference intervals were sex-specific and were verified using healthy reference samples from the CALIPER biobank based on CLSI criteria. It is important to note that the comparisons performed between the Abbott and Beckman Coulter assays make no assumptions as to assay accuracy or which system is more correct/accurate. CONCLUSION: The majority of CALIPER reference intervals were transferrable to Beckman Coulter AU assays, allowing the establishment of a new database of pediatric reference intervals. This further expands the utility of the CALIPER database to clinical laboratories using the AU assays; however, each laboratory should validate these intervals for their analytical platform and local population as recommended by the CLSI.

Comparison and Analysis of the Reference Intervals of 9 Serum Routine Chemical Analytes between the Current Application of Clinical Laboratories and the Latest Health Industrial Standards Draft for Approval / 现代检验医学杂志

Objective To investigate the current application status of reference intervals in routine chemistry and compare with the current health industry standards draft for approval.Methods By using web-based external quality assessment (EQA)software system,collected the submitted data from the laboratories which attended national reference intervals inves-tigation,used professional statistical software to analyze the data.Results 385 laboratories had submitted the investigation results.The vast majority of the analytes of attended laboratories had significant statistical differences in comparison with the health industry standards draft for approval in no grouping and not filled groups[t = - 55.435 ~ 17.070,P < 0.05, 86.1% (31/36)].Only a few of laboratories’reference interval had been grouped (approximately 20%).There were some differences in grouping rules between laboratories and standards.Even though some of the laboratories adopt the grouping rules as same as the standards,there were still big differences in reference intervals between the laboratories and the stand-ards[t=-39.365~13.155,P <0.01,62.5% (10/16)].Conclusion The reference intervals of routine chemistry analytes suggested by the health industry standards draft for approval had quite big differences from the reference intervals used in current clinical laboratories daily work.It is important to propel the authority health industry standards to use in the daily work of clinical laboratories.The evaluation and validation of using them should be done first.