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.

Handling of hemolyzed serum samples in clinical chemistry laboratories: the Nordic hemolysis project.

Background Some clinical chemistry measurement methods are vulnerable to interference if hemolyzed serum samples are used. The aims of this study were: (1) to obtain updated information about how hemolysis affects clinical chemistry test results on different instrument platforms used in Nordic laboratories, and (2) to obtain data on how test results from hemolyzed samples are reported in Nordic laboratories. Methods Four identical samples containing different degrees of hemolysis were prepared and distributed to 145 laboratories in the Nordic countries. The laboratories were asked to measure the concentration of cell-free hemoglobin (Hb), together with 15 clinical chemistry analytes. In addition, the laboratories completed a questionnaire about how hemolyzed samples are handled and reported. Results Automated detection of hemolysis in all routine patient samples was used by 63% of laboratories, and 88% had written procedures on how to handle hemolyzed samples. The different instrument platforms measured comparable mean Hb concentrations in the four samples. For most analytes, hemolysis caused a homogenous degree of interference regardless of the instrument platform used, except for alkaline phosphatase (ALP), bilirubin (total) and creatine kinase (CK). The recommended cut-off points for rejection of a result varied substantially between the manufacturers. The laboratories differed in how they reported test results, even when they used the same type of instrument. Conclusions Most of the analytes were homogeneously affected by hemolysis, regardless of the instrument used. There is large variation, however, between the laboratories on how they report test results from hemolyzed samples, even when they use the same type of instrument.

Status on fasting definition for blood sampling in the Nordic countries - time for a harmonized definition.

The preanalytical phase contains a vast number of practices whose variation may influence the results of laboratory testing and should, therefore, be standardized. The Working Group on Preanalytical Phase of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM WG-PA) has suggested a standardization of venous blood specimen collection (VBSC) requirements for fasting samples including 12 h fasting time and water ad lib in the morning prior to specimen collection. The Nordic Scientific Preanalytical Working Group investigated the fasting definitions used in the Nordic countries. The Internet was assessed for stated fasting definitions of official organizations, larger laboratories, or laboratory groups. Fasting instructions for VBSC generally demanded patients to abstain from alcohol a day prior to, and to abstain from coffee, tea, smoking, and snuff intake in the morning of VBSC. Norway had a national fasting definition. Required fasting times varied from 8 to 14 h. The amount of water allowed in the morning of VBSC varied from ad lib to half a glass of water. The list of analytes, where fasting was required, held 9-15 analytes except for Finland with 65 analytes. Implementation of the EFLM WG-PRE standardization of VBSC requirements for fasting samples would decrease preanalytical variability and be beneficial for medical decisions and patient data comparison. We suggest the laboratories in the Nordic countries to implement the suggested fasting requirements, which are in line with those used when fasting reference intervals were established in the Nordic reference interval project.

Measurements for 8 common analytes in native sera identify inadequate standardization among 6 routine laboratory assays.

BACKGROUND: External quality assessment (EQA) with commutable samples is essential for assessing the quality of assays performed by laboratories, particularly when the emphasis is on their standardization status and interchangeability of results. METHODS: We used a panel of 20 fresh-frozen single-donation serum samples to assess assays for the measurement of creatinine, glucose, phosphate, uric acid, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. The commercial random access platforms included: Abbott Architect, Beckman Coulter AU, Ortho Vitros, Roche Cobas, Siemens Advia, and Thermo Scientific Konelab. The assessment was done at the peer group level and by comparison against the all-method trimmed mean or reference method values, where available. The considered quality indicators were intraassay imprecision, combined imprecision (including sample-matrix interference), bias, and total error. Fail/pass decisions were based on limits reflecting state-of-the-art performance, but also limits related to biological variation. RESULTS: Most assays showed excellent peer performance attributes, except for HDL- and LDL cholesterol. Cases in which individual assays had biases exceeding the used limits were the Siemens Advia creatinine (-4.2%), Ortho Vitros phosphate (8.9%), Beckman Coulter AU triglycerides (5.4%), and Thermo Scientific Konelab uric acid (6.4%), which lead to considerable interassay discrepancies. Additionally, large laboratory effects were observed that caused interlaboratory differences of >30%. CONCLUSIONS: The design of the EQA study was well suited for monitoring different quality attributes of assays performed in daily laboratory practice. There is a need for improvement, even for simple clinical chemistry analytes. In particular, the interchangeability of results remains jeopardized both by assay standardization issues and individual laboratory effects.

Validation of the Hemo_Control instrument for determination of B-haemoglobin concentration in primary health care.

OBJECTIVE: The aim of this study was to evaluate the analytical performance of a new portable haemoglobinometer, Hemo_Control (EKF-diagnostic, GmbH, Germany), which measures haemoglobin concentration in venous and capillary samples. METHOD: The within series and between series imprecision of the Hemo_Control instrument were calculated after measuring the concentration of venous samples under standardized conditions; by experienced laboratory technicians in a hospital laboratory, and venous and capillary samples under conditions similar to where the instrument is intended for use; by personnel at two primary health care centres. The bias of the Hemo_Control instrument was calculated as the difference between its results and results obtained with a Coulter LH 750 instrument traceable to the ICSH reference method. RESULTS: The uncertainty of the Hemo_Control instrument for venous samples was lower than the quality goal of +/- 5% considered acceptable for patient care. High within series imprecision (5.5%) was observed for measurements of capillary blood samples in one of the primary care centres, whereas adequate analytical performance was obtained at the other centre. The Hemo_Control instrument showed negligible bias of +0.8 g/L for both venous and capillary samples in primary health care. CONCLUSION: The observed uncertainty indicates that Hemo_Control is appropriate for near patient testing using venous samples. Capillary samples may be used if sampling skills are adequate.