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Harmonization of units and reference intervals of plasma proteins: State of the art from an External Quality Assessment Scheme
Full text linkThe need to harmonize laboratory information is particularly intense in the field of plasma proteins, considering their clinical impact and relevance in monitoring diseases. We evaluated units and reference intervals (RIs) utilized by participants of the External Quality Assessment Scheme (EQAS) for plasma proteins of the Centre of Biomedical Research. Moreover, we evaluated inter-laboratory analytical variability from 2001 to 2017. The census of participants' units employed in 2017 showed that for albumin (ALB), ~66% of laboratories still used dL instead of L, and for most other proteins, ~70% still expressed the results in mg/dL. Laboratories primarily used the RIs reported in the packaging inserts of their analytical systems, but for each protein, there was a wide variability of RIs, also among laboratories using the same analytical method. Mean CVs% of the 13 certified proteins in the last five EQA cycles ranged from 3.8% of haptoglobin (HPT) to 12.4% of α1-antitrypsin (AAT) and decreased from 2001 to 2017 for most of them, in particular for C3, ALB, α2-macroglobulin (A2M), HPT and transferrin (TRF). In the face of a reduction in inter-laboratory variability for a lot of proteins, there has not been a substantial change in the units and in the RIs used by the participants. To change old habits is difficult and requires coordination and collaboration. The EQAS plays an important role in the assessment and monitoring of all elements that contribute to the formulation of laboratory information and may be useful to contribute to their harmonization
Performance evaluation of 14 specific proteins measurement checked by an External Quality Assessment Scheme
No full textAims of the study: To evaluate the state-of-the-art of 14 specific proteins measurement; to evaluate the laboratories’ performance and the degree of harmonization in reporting results of participants in the External Quality Assessment Program of the Centre of Biomedical Research (CRB). Methods: Overall and system-related inter-laboratory analytical variability (mean CVs%) and between-system differences (mean bias%) were evaluated from data of six EQA cycles 2013–2018. Moreover, we evaluated the analytical performance of participants as well as the units used to express proteins results. Results: Overall inter-laboratory variability ranged from 3.8% for haptoglobin (HPT) to 12.5% for α1-antitrypsin (AAT) and decreased for IgA, α2-macroglobulin (A2M) and transferrin (TRF). Mean CVs% were generally higher for Siemens BN and Beckman Immage immunonephelometric systems, but 7.0% was observed for BN (IgA, C4, AAT, transthyretin TTR), Siemens Vista (IgA, C4) and Immage (C4), whereas mean bias < −7.0% was found for Immage (AAT), Beckman AU (IgM) and Roche Cobas (C4, TTR, C-reactive protein). The laboratories’ performance within the limits ranged from 85.1% of albumin (ALB) to 97.2% of HPT. The census of units employed in 2018, demonstrated that ~ 70% of laboratories still express the results in mg/dL. Conclusions: Despite a reduction in inter-laboratory variability for some proteins, different analytical systems showed both proportional and constant bias between methods. Units used by participants have not been substantially changed and dL is still largely used. The CRB EQA Program, with its performance data sets, is a valuable resource for laboratories and IVD manufacturers and support the goals of harmonization
Evaluation of clinical cases in External Quality Assessment Scheme (EQAS) for the urinary sediment.
No full textBACKGROUND:
The few available External Quality Assessment (EQA) programs on urinary sediment rarely include an evaluation of clinical cases. The present paper provides a descriptive analysis of clinical cases included in the Italian EQA program on urinary sediment.
METHODS:
Ten cases were presented over a 5-year period (2007-2011). Each clinical case included a brief clinical history, some key laboratory data and four key urinary sediment particles obtained by phase contrast microscopy. The clinical diagnoses indicated by participants, chosen among four or five proposed, were evaluated only for those who had been able to correctly identify all four urinary sediment particles. The results of each survey were then evaluated, scored and commented on.
RESULTS:
The numbers of participants for the 10 surveys ranged from 268 to 325. Throughout surveys, only 63.9%±17.0% (range 39.6%-88.7%) of participants achieved access to clinical diagnosis. Of these, 90.2%±8.5% (range 73.7%-98.1%) were able to indicate the correct diagnosis.
CONCLUSIONS:
Our findings demonstrate that once the correct identification of urinary sediment particles is obtained, most participants are able to associate urinary findings with the respective clinical conditions, thus establishing the correct diagnosis
Ventricular myosin and creatine-kinase isoenzymes in hypertensive rats treated with captopril.
No full textHypertension. 1989 Nov;14(5):556-62.
Ventricular myosin and creatine-kinase isoenzymes in hypertensive rats treated with captopril.
Pauletto P, Nascimben L, Piccolo D, Secchiero S, Vescovo G, Scannapieco G, Dalla Libera L, Carraro U, Pessina AC, Dal Palù C.
Source
Institute of Clinica Medica I, University of Padova, Italy.
Abstract
In the myocardium, myosin and creatine kinase isoforms possess different capacities for using O2 and energy-rich phosphates. We studied electrophoretically the distribution of these isoforms in 19 hypertensive rats (two-kidney, one clip model of hypertension) and in age-matched controls. After 6 weeks of hypertension, seven rats were treated with captopril (2 mg/kg daily) for 4 weeks, six were left hypertensive for another 4 weeks, and the remaining rats were killed under ether anesthesia. In the latter, ventricular mass was significantly higher than in controls; V3 isomyosin was 32.3 +/- 6.8% versus 0%, and both creatine kinase-MB and -BB were increased at the expense of creatine kinase-MM (creatine kinase-MB = 29 +/- 2.8% vs. 14.7 +/- 1.8%, p less than 0.001; creatine kinase-BB = 3.1 +/- 0.6% vs. 1.7 +/- 0.8%, p less than 0.001). After 10 weeks of hypertension, ventricular mass, V3 isomyosin, and both creatine kinase-MB and -BB isoforms were found to be persistently higher than in controls. At the same time, captopril-treated rats showed reduced but not normalized blood pressure levels, normalized ventricular mass, and prevalence of the V1 isomyosin (56.9 +/- 22% vs. 47.9 +/- 23.8% in normotensive controls, p = NS). However, higher levels of creatine kinase-MB and -BB were still found in these rats in comparison with the normotensive controls (creatine kinase-MB = 22.4 +/- 5.4% vs. 15.8 +/- 2.8%, p less than 0.025; creatine kinase-BB = 2.3 +/- 0.1% vs. 1.8 +/- 0.3%, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
PMID:
2680963
[PubMed - indexed for MEDLINE]
Free full tex
Precipitation method for separating and quantifying bone and liver alkaline phosphatase isoenzymes.
No full textWe evaluated a method for quantifying bone isoenzyme of alkaline phosphatase (ALP) which utilizes wheat-germ lectin to precipitate this traction. In precision studies, CVs ranged from 3.2 to 11.4% (within-day) and from 3.7 to 11.5% (day-to-day). The assay procedure was linear to 1100 U/L and was easily adapted to automated kinetic measurement. Comparison of the precipitation method with an affinity electrophoretic method, which utilizes cellulose acetate as a support, demonstrated a satisfactory coefficient of correlation (r = 0.886). The reference range was determined in sera from 188 healthy adult subjects. The distribution of bone ALP values was also studied in 73 healthy children and in 30 healthy adolescents. To evaluate the clinical applicability of the method, the bone isoenzyme was determined in samples from several groups of subjects (pregnant women, patients with hepatobiliary diseases, patients with hepatocellular carcinoma without skeletal involvement, and patients with bone, liver or lymph node metastases). We found the method suitable for routine determination of bone alkaline phosphatase and for the screening of bone metastases. Because of its technical simplicity and satisfactory analytical performance, it can be used instead of the heat-inactivation procedure
Appropriateness of cholesterol and triglycerides reporting checked by External Quality Assessment programs
No full textBACKGROUND:
The recommendations of the Second Joint Task Force of European and Other Societies on Coronary Prevention and the third Adult Treatment Panel report (ATPIII) released by the National Cholesterol Education Program are based on accumulating evidence concerning the contribution of lipoproteins and other risk factors in the development of coronary heart disease (CHD). The laboratories play an important role in the successful adoption of these guidelines.
METHODS:
In External Quality Assessment (EQA) programs managed by the Center of Biomedical Research, results and respective reference intervals (RI) are sent as laboratory's medical form. We assessed how well the 200 participants to EQA scheme 2002 for clinical biochemistry reported total cholesterol (TC) and triglycerides (TGs) results according to either European or National Cholesterol Education Program (NCEP) guidelines.
RESULTS:
Only 18% of laboratories reported total cholesterol concentrations correctly in terms of desirable, borderline-high, and high risk for the CHD development, 12% reported a single desirable value (180, 190, or 200 mg/dl), and 70% reported the RI (85 laboratories in the whole interval, 34 are the only upper reference limit and 15 are the desirable value in addition to RI). The upper reference limit was 200 mg/dl in 65% of cases, but 32% of laboratories presented higher limits, reaching values as high as 250-260 mg/dl. Only the 3.7% of laboratories reported triglyceride concentrations in terms of risk-oriented ranges for the CHD development, 6.8% the single desirable value, and 89.5% the RI.
CONCLUSION:
Our study demonstrates that the current practice of reporting results for cholesterol and triglycerides does not follow the guidelines, and appropriate changes are required to be mad
The standardization of plasma protein checked by an external quality assessment scheme (EQAS)
No full textInterpretative comments and reference ranges in EQA programs as a tool for improving laboratory appropriateness and effectiveness
No full textINTRODUCTION:
Laboratory information is generated when a meaning is given to certain data. This is usually achieved by comparing a laboratory test result with the reference range/decisional limit (RL), and by providing consultation for the interpretation of data, advice, and follow-up testing.
AIM:
In this paper, we investigate factors affecting the conversion of data into useful information with regard to biochemical markers of myocardial damage (CK-MB mass, myoglobin, and troponins), in view of their importance in detecting myocardial necrosis. Our aim was to report results obtained in order to verify the consensus between laboratories with reference to interpretative comments and the reference ranges/decisional limits added to clinical reports.
METHODS:
A questionnaire and simulated medical reports on three different patients were distributed to participants (94 laboratories) in the 2001 cycle of the External Quality Assessment (EQA). Moreover, we analysed 113 medical reports sent by laboratories during the most recent EQA cycle 2002, and checked the number of different RLs used, both independent and within the diagnostic system used. We also compared each laboratory result of a control sample, obtained in the 2002 cycle, with declared RL in order to verify the clinical significance of results ("normal" or "pathological") for troponin I and CK-MB.
RESULTS:
Our findings show that few laboratories regularly add interpretative comments to medical reports. On the contrary, they cooperate with clinicians who require consultation, advice, and information for the appropriate use of biochemical markers. There is a general consensus among participants regarding probable syndromes suggested by the interpretation of the same result and most laboratories also agree on further investigations to be carried out for several diseases. Concerning RL, the data demonstrate that numerous different RLs are used to report the results of the biochemical markers evaluated, both when considered independent of the diagnostic system used and within the diagnostic system used.
DISCUSSION AND CONCLUSIONS:
The biochemist does not have the opportunity to verify the efficacy of the interpretation that he/she provided. An audit of this activity is therefore required to allow the laboratory to monitor its own performance and to assure good practice. The evaluation of interpretative comments, through specific surveys, should be a prime objective of EQA organisers. Well-designed EQA programs can, moreover, support laboratories in establishing appropriate RL and in verifying the clinical significance of their results with respect to that of other laboratories. Our survey on interpretative comments and the analysis of the RLs further demonstrate how laboratory medicine can contribute to the objective evaluation of the patients' health status
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