experience with quality assurance programme on Coulter model S7

A program of quality assurance technique was carried on Coulter Model S7 in Ain Shams Specialized Hospital. The main procedure used in calibration was using fresh whole blood analysed by either manual techniques, or the use of well calibrated digital counter. Monitoring quality control was also carried out by using data derived from patient specimens. Quality control material was not used even in calibration and even in monitoring quality performance because of their high cost, short life span and their unreliable assayed values. Some of our techniques was applied daily, others weekly or whenever needed. These methods proved to be valid, cheap and effective. It serves as a major base for quality assurance of our Coulter S7

Evaluation of serum iron by standard colorimetric method and atomic absorption spectrophotometry

Serum iron concentration was done on 30 normal samples using both atomic absorption and standard colorimetric method. The atomic absorption method gave results significantly higher than that obtained by manual techniques [P<0.05]. Correlation study showed a significant positive correlation. For evaluation of the two techniques, both methods are highly precise although atomic absorption is more precise than the manual technique [C.V. equal 2.7 and 8.9% respectively]. Moreover both techniques were linear in a very wide range and atomic absorption was more sensitive than the manual one, the least detectable limits were 26 and 50 ug/dl respectively. As for interference study, hemolysis was found to interfere markedly with iron determination by atomic absorption while bilirubin or lipid have no significant effect on it. Finally we found that both techniques can be used perfectly for the determination of serum iron but the chemical method is still the cheapest and the more convenient one

Antithrombin III estimation immunological versus chromogenic substrate in bilharzial liver fibrosis

Fourty one patients with bilharzial liver fibrosis were investigated for antithrombin III [AT III] by chromogenic substrate method versus radial immuno-diffusion method. A control group of sixteen healthy young adults was also assayed for comparison. There was a significant AT III deficiency in bilharzial liver patients, mainly due to defective synthetic ability of the liver and low grade DIC. A significant positive correlation was found between results of ATIII antigen as measured by chromogenic substrate method. However the antigen values were significantly higher than the activity, possibly due to presence of abnormal nonfunctioning antigen molecules. By comparing the two methods, it was found that the technique of radial immunodiffusion method is much easier with single step, thus it is more precise with less coefficient of variation. However, the chromogenic substrate method offers many advantages. It is more sensitive than the immunodiffusion method and it takes very short time with a relative technical simplicity. Both methods are of equal high specificity and show good correlation between expected and observed results. Cost study showed that both methods were nearly equal. Although the chromogenic substrate method needs a special equipment, however the low reagent consumption reduces much the cost per assay