Évaluation du réactif ultrasensible de dosage de la CRP sur le dimension® RXL

C-Reactive Protein (CRP) is the major phase protein. Prospective studies have shown a positive correlation between the risk of developing atheroscleorotic complications and CRP concentration. High-sensitivity methods for CRP measurement are needed for this purpose. During our experimental work, we evaluated the analytical performances of the Dimension® RXL Revised C-Reactive Protein (RCRP) according to the technique validation protocol (Valtec 97). The results we obtained allow to confirm the excellent analytical performances and the low detection limit of this new reagent. With regard to the technique comparison, to the BN II and the Cobas® Integra 700, the three methods demonstrated a good correlation but exhibited differences in patients results. Additional standardization efforts are required.     

Évaluation du réactif tina quant® récepteur soluble de la transferrine sur l'analyseur Cobas® Integra 700

Today, soluble transferrin receptor determination is often realized in biochemistry laboratories. The concentration of soluble transferrin receptor in serum is reported to be useful in the diagnosis of iron deficiency, especially for patients with concurrent chronic disease, where routine tests of iron status are compromised by the inflammatory condition.During our experimental work, we evaluated the analytical performances of the Tina Quant^® sTfR with Roche Diagnostics Cobas^® Integra 700. Precision, measurement domain, reference range and correlation with R&D Systems Quantikine^® IVD^® were studied. Results are analytically acceptable. Tina Quant^® sTfR is easily adaptable to an automated chemistry analyzer and is cheaper in comparison with Quantikine^® IVD^®.     

Évaluation des performances analytiques de l'analyseur cobas®integra 700

The Cobas Integra 700 is a closed multiparametrical analyser with captive reagents allowing to test usual biochemistry parameters (electrolytes, substrates and enzymatic activities), but also therapeutic drugs, drugs of abuse, toxics and specific proteins. During our experimental work, we evaluated the analytical performances of the Cobas Integra 700 according to the Société française de biologie clinique (SFBC) technique validation protocol (Valtec 97) for the following analytes: sodium, potassium, iron, urea nitrogen, creatin kinase, amikacin, IgG, albumin and C-reactive protein (CRP) in blood, sodium, potassium, creatinine and proteins in urine. The results we obtained allow to confirm the excellent analytical performances regarding imprecision and operational characteristics. On the other hand, concerning some analytes, we noticed an inaccuracy with the selected comparison techniques, especially for CRP, urine sodium and proteins. In conclusion and considering its practicability (automated daily servicing, software user-friendliness, automated reagents reconstitution…), the Cobas Integra 700 seems to us well suited for biochemistry laboratories performing from 1,500 to 3,000 daily tests.     

Évaluation de l'automate d'hématologie Sysmex SE 9500®

The Sysmex SE 9500^® evaluation was carried out during three weeks in the Teaching Hospitals in Nice, France. It is a new generation automated haematology analyser performing the complete blood count and differential leukocyte count.It is designed to use electrical impedance, radiofrequency, absorbance spectrophotometry, cytochemical differential and a specific IMI channel for immature granulocytes.The results (linearity, carryover, repeatability, reproductibility and stability) were very satisfactory and its ergonomics was appreciated. 510 complete blood counts were compared with those produced with our current analyser, the Coulter STKS^®. For all studied parameters, the correlation was perfect except for the MCHC and the basophilia, a normal finding when comparing analysers.Comparing 635 differential leukocyte counts done with the Sysmex SE 9500^® on one side and with optical microscopy on the other side showed a very good sensitivity (93 %) and a correct specificity (80 %). Its excellent negative predictive value (95 %) appeared as a master trump.The SE 9500^® is up to biologists expectations for a new generation automated haematology analyser.     

Évaluation du CELL-DYN 4000® Abbott automate d'hématologie

The CELL-DYN 4000® Abbott evaluation was carried out during fivteen days in which 4160 blood samples were tested. The CELL-DYN 4000® quantitative performances were very satisfactory especially showing linearity over a wide concentration range and absence of carry-over.500 complete blood counts were compared with those produced with the Coulter STKS®, our current analyser. For all the studied parameters, the correlation was perfect (r > 0,9) except for MCHC and basophilia. In order to compare qualitative parameters, 601 blood smears, collected from intensive care and hematology departments, were examined. The reliability of flags showed no difference between the two analysers. The global performances of CELL-DYN 4000® were as follows : review rate 35 %, sensitivity 69 %, specificity 83 % and efficiency 78 %. Most of the false positives and false negatives corresponded to myelemia. No case of false negative was noted due to the presence of blasts. The CELL-DYN 4000® was greatly appreciated for its ergonomics and user-friendliness.     

Intérêt des dosages d'insuline,peptide C et hémoglobine glyquée dans le suivi des patients diabétiques

The diagnosis of diabetes mellitus was established by WHO in 1985 and was reviewed by an international Expert Committee in 1997. The revised criteria of fasting plasma glucose for the diagnosis has been based on 7 mmol/L (1,26 g/L). Prevalence of diabetes mellitus should be enhanced in the next few years. Cost of diabetes due to its complications is about 93% of the total cost. Insulin and peptid C do not have any interest in diabetes mellitus survey. Glycated hemoglobin (HbA_1c) which reflects long term glycation is an objective and commonly used parameter for monitoring diabetes. DCCT results have shown the association between chronic hyperglycemia (tested with HbA_1c) and microangiopathies. Its utilization is a major part of the care of patients with diabetes mellitus.     

Érythropoïétine et dopage

Human erythropoietin (Epo) is a 30,4 kDa glycoprotein. It is composed of 165 amino acids and 4 carbohydrate side chain. Tissue hypoxia is the main stimulus for epo synthesis. Epo maintains red cell production by inhibiting apoptosis of erythrocyte progenotors, and by stimulating their proliferation and differentiation into normoblasts. Since the end eighties recombinant DNA technology has led to the large scale production of human erythropoietin for use as a antianaemic drug in patients with chronic renal failure. Quickly some athlete have used this hormone to increase their aerobic power and consequently their results specially in endurance sports. After several years of research now it is possible to detect it. The firts control took place during Sydney Olympic Games.     

Évaluation des performances et de la praticabilité de l'automate de cytobactériologie sysmex UF-100™ pour la prédiction de l'infection urinaire

In three public health routine laboratories, we have evaluated the performance and the usefulness of the automated flow cytometer Sysmex UF-100™ (Sysmex France, Villepinte, France) for urinary sediments. 612 urine specimens were tested for cytobacteriological count using the instrument and compared with conventional manual methods used in these laboratories.With the interpretive cut off values proposed by the manufacturer, the results obtained show 90 % specificity, 80 % sensibility as well as a positive predictive value of 70 % to detect urinary infections by the automated method. The “false negative” rate was only 2,8 %. This can be reduced by decreasing cut off values used to calculate the predictive index of infection (leucocyturia and number of bacteria/ml), without affecting the acceptable rate of « false positive å. The instrument proved to be able to replace the manual method used to analyse urinary sediments, and can significantly reduce the number of cultures performed on non infected samples. It improves standardisation and precision of leucocyte and bacteria counts, significantly reduces time for testing, and optimises the workflow of the laboratories.