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J Henny

Publications and source records attributed to J Henny.

42 records · Page 3Linked to original sources
PubMedDate not supplied

[Harmonization of practices: application to the measurement of enzymatic activities used in prevention, screening, diagnosis and therapeutic monitoring].

The large metrological variation (CV, about 25%) observed between laboratories, at the national French level, for the measurement of enzymatic activities results in a loss of efficiency in using laboratory results. Current data show that the standardisation of methods is insufficient to solve this problem and needs to be completed by an harmonisation of the practices including the use of a common reference (calibrator). The present work, carried out by the joint working group between laboratories of the Centres for Periodic Health Examination and the French Society of Clinical Biology (SFBC), deals mainly with the feasibility and evaluation of the improvement of the consistency of the results. Twenty laboratories participated in this study. Five independent surveys were conducted during an height month period. Two enzymes were selected because of their clinical importance and their interest in prevention, screening, diagnosis or epidemiology: ALT (alanine aminotransferase) and GGT (gamma-glutamyltransferase). In each survey three kinds of samples i.e. control sera, candidate calibrators and human serum pools, each of them at two levels of activity (one physiological and the other pathological) were measured in duplicate. The low intra-laboratory imprecision and the high degree of the standardisation of used methods, due to an important effort previously done in this field, permitted to consider a common calibration. The stability and mainly the commutability, i.e. the ability for the candidate calibrator to show a behaviour similar to that of human samples towards the used methods, allowed to reduce the inter-laboratory variation by a half to two third-fold, reaching a coefficient of variation < 5% similar to those observed for cholesterolemia or glycemia. This level of consistency should permit to use common reference limits and common decision limits, after validation of this approach in real practice. The consequences of the harmonisation of practices, extended to the all laboratories, exceed largely the scope of this study. The reduction of the uncertainty and a better approach of the accuracy for the measurement of enzymatic activities should led to a real benefit for the patients in terms of prevention, screening, diagnosis or therapeutic monitoring and consequently for the public health.

Alanine Transaminase↗
PubMedDate not supplied

[Reference limits for urine sediments performed on Sysmex UF-50].

The Sysmex UF-50 is an automated flow cytometer for urine sediments analysis. Interpretation of the results needs establishment of reference limits for the different constituents measured. First of all, we checked precision of measurements and stability of urines during transportation. Then, urine samples from 4 to 95 year old subjects were examined with the UF-50, by visual microscopy and test strips. Distributions of results for erythrocytes, leukocytes, epithelial cells, casts, bacteria and conductivity were described in a sample of 680 subjects (364 men and 316 women), with creatininemia below 140 micromol/L, consuming no drugs and for women without intra uterine device and apart from menstruation period. Then, the results were compared with those obtained in groups selected on microscopic analysis and test strip results. UF-50 sensitivity and specificity were 77.5% and 88% for 15 erythrocytes/microL in reference to microscopic urinalysis, they were 91.3% and 87.3% for 15 leucocytes/microL. The reference sample was defined with negative microscopic results. The upper reference limits (centile 97.5) were 16 red blood cells/microL for men 14.5 for women, 13.5 and 33 leucocytes/microL, 8 and 19 epithelial cells/microL, 1,3 and 0,4 casts/microL, 5 500 et 7 700 bacteria/microL, 36,2 et 34,6 conductivity mS/cm. The Sysmex UF-50 is a suitable analyser for urinary sediments. Reference limits may be different from usual reference limits due to variability in performances of other methods.

Adolescent↗
PubMedDate not supplied

[Determination of glucose, proteins, blood and leucocytes in urines: evaluation of automated analyzer Aution Max AX 4280].

The aim of this study was to evaluate the automated urine test strip analyzer Aution Max AX 4280 which uses strips able to measure 12 urinary parameters. For precision study, we considered glucose, protein, blood, leukocytes, nitrite, and pH and the four first were compared with usual methods: chemical measurement or microscopic examination. Reproducibility of the semi quantitative results was determined as the proportion of results falling into the same concentration range. Within-run reproducibility assessed using urine specimens were between 83% and 96%. Between day on quality controlled materials, it was higher (96%), and leukocytes were shared between two classes 250 and 500 cells/microL. For glucose and proteins, linearity was good and comparison with quantitative methods yielded high correlation. The false negative fraction was low and there was no false positive results. For blood, fraction of false positive was 7.5% for 0.3 mg/L of hemoglobin compared with microscopic analysis and false negative fraction was 1.3%. For leukocytes, false positive fraction was 4%, false negative one was 7.8%. These results, values for sensitivity, specificity, predictive positive value, predictive negative value permitted to determine the cut-off values to realize second levels analysis: proteins are measured from 0.30 g/L, glucose from 2.8 mmol/L, microscopic urinalysis was performed from hemoglobin more than 0.3 mg/L and leukocytes more than 25 cells/microL.

Adolescent↗
PubMedDate not supplied

[Reference values of apolipoproteins A1 and B. Contribution of international standardization. Travail collaboratif entre la SFBC, l'Arcol et le SFRL].

The utilization of two WHO reference materials, liquid and lyophilized, permitted international standardization of apolipoprotein measurements. We report here the results of a collaborative study between Arcol, SFBC and SFRL in order to establish reference ranges for apo A1 and B on nine standardized systems. A population of 1027 men and women supposed healthy, 4 to 60 year old, have been selected in two Centers for Preventive Medicine. The serum samples were aliquoted frozen at -20 degrees C the day of sampling and analysed by the manufacturers with IFCC standardized calibrants. A specific quality control was performed using a frozen pool of sera. For apo A1, the centile 2.5 of the reference population varies from 1.04 to 1.16 g/l. The range values for the centile 97.5 varies from 1.87 to 2.24 g/l. For apoB, the centile 2.5 varies from 0.43 to 0.57 g/l, and the centile 97.5 from 1.30 to 1.39 g/l. Only one system has a problem of dispersion with an upper limit equal to 1.20 g/l. These results improve that international standardization allowed actually a good comparability of the results, especially for apoB.

Adolescent↗
PubMedDate not supplied

[Criteria for addition of apolipoprotein B measurement during routine health screening examinations: validation in a Stanislas cohort. The Biologist's Group of the Health Examination Center].

The purpose of this study was to determine the criteria in which apolipoproteins AI and B should be performed during periodic health screening examinations. Clinically, the results of apolipoproteins AI and B are most useful when there are minor lipid perturbations (cholesterol and triglycerides), but their routine determination is not justified. Several mathematical models, defined by discriminate factorial analysis, have been studied. The one based uniquely on cholesterol and triglyceride concentrations was the most efficient in identifying patients in whom apolipoprotein B should be determined. In contrast, no model was found for the indication of apolipoprotein AI determination. Data from a population different from that used for the model establishment were used to validate the model. This strategy, determining criteria for additional measurement of apolipoprotein B in a general population, is of clinical interest because it may provide complementary information for subjects with atherogenic risk. Moreover, it is of economical interest because it has the potential of limiting complementary testing and its associated costs.

Adult↗