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A Pilo

Publications and source records attributed to A Pilo.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Comparison of immunoassays for tumor markers CA 19-9, CA 15-3 and CA 125: data from an international quality assessment scheme.

Data collected in the 1993 and 1994 cycles of an international external quality assessment (EQA) program and in a national multicenter collaborative study were cumulatively analyzed to evaluate the standardization of the methods currently in use for the assay of mucinous tumor markers CA 19-9, CA 15-3 and CA 125. On average the between-laboratory variability was 15.2 and 16.0 CV% for CA 15-3 and CA 125 respectively; the between-laboratory variability found for CA 19-9 was markedly worse (mean 28.3 CV%). The variability component attributable to systematic differences between different methods/kits was relatively small for CA 15-3 and CA 125 (18% and 24% of the total variability) but markedly larger for CA 19-9 (48% of the total variability). The agreement of CA 19-9 results worsened in the last few years when new nonisotopic techniques became available. The precision of the methods/kits most used in the survey ranged from 9.9 to 13.3 CV% for CA 125 and from 11.6 to 13.9 CV% for CA 15-3. For these two tumor markers the precision of the traditional IRMAs does not appear different from that of the new fully automated nonisotopic techniques. The precision of CA 19-9 methods was on average worse (from 11.7 to 19.6 CV%) although two automated systems exhibited a precision better than that of IRMAs. In conclusion, the results of this study indicate that CA 15-3 and CA 125 are satisfactorily assayed whereas CA 19-9 assay appears affected by larger differences between methods and by poorer precision of laboratories and kits.

Antigens, Tumor-Associated, Carbohydrate↗
PubMedDate not supplied

External quality assurance of the carcinoembryonic antigen (CEA) assay: main findings in six years' experience.

In 1984 we initiated a national external quality assessment (EQA) program (supported by the Italian National Research Council, CNR) for the CEA assay; at present, about 200 Italian laboratories are participating in the program. The laboratories assayed the quality control (QC) samples according to their routine procedures and returned the results together with the name of the method/kit they used. The collected results were computer-processed and reports were sent back to the participants. A significant reduction of the CVt (mean between-laboratory agreement) of the CEA assay was observed throughout the EQA survey (from 35% in 1985 to 20-25% in the last cycles). In order to better clarify the differences in variability observed in the first QC cycles against the last ones, we used the ANOVA technique to evaluate the components of variability. The improvement in between-laboratory agreement was mainly due to the reduction of the between-kit component (from 30.5% to 15.2%), rather than to the smaller decrease observed for the within-kit variability (from 18.4% to 14.0%). The results reported for QC samples from different materials showed differences in the between-lab variability and substantial changes of the kit biases, thus suggesting a different specificity of the antibodies used in the various method/kits against different families of CEA molecules. Considerable uncertainty was also encountered in the clinical classification of low pathological samples, which seems mainly due to the variability in cut-off values used by the laboratories for the clinical assessment of the same analytical results. Our data indicate a progressive increase in the reliability of CEA determination during our study and confirm that EQA has improved the reliability of analysis carried out by the participating laboratories, thus stimulating the kit manufacturers to provide more reliable products.

Antibody Specificity↗
PubMedDate not supplied

External quality control survey for alpha-fetoprotein assay.

Starting from 1984 we organized an interlaboratory quality control (QC) survey for the tumor marker AFP in which 100-150 laboratories have been involved. Seven consecutive QC cycles have been carried out during the period 1984-1988; 15-20 samples have been prepared and sent in each cycle. The 11 kits more used in the survey, which use three different immunological methods (3 kits EIA, 3 kits RIA, and 5 kits IRMA) were evaluated. Since the results of AFP assays were expressed as ng/ml of different local standards of the various kits, the participants were asked to convert their results in UI/ml of the 1st IRP 72/225 distributed by WHO. The total variability of AFP assay resulted approximately constant (19.9-24.7 CV%) during the all QC period. The validity of the consensus mean of AFP determinations obtained in the survey and assumed as reference value has been checked by recovery experiments. Regression analysis indicates that the consensus means found in these samples are in very good agreement with the added AFP. The analytical performance achieved by the most popular methods/kits, observed in the last period, are also reported.

Italy↗
PubMedDate not supplied

A method for retracing the putative antigen/antibody ratio of immune complexes in biological fluids.

It is well known that immune complex (ICs) diseases are caused by a number of factors which influence the localization, clearance and inflammatory potential of ICs. Several studies suggest that the Ag/Ab ratio is one of the most important of these. Previous studies have clarified that IC detection methods which differ, either in their recognition unit or in the phase used (solid or liquid), show a very poor correlation with each other. This study was developed in order to verify the hypothesis that different methods recognise different kinds of ICs on the basis of their Ag/Ab ratio. We used 3 homogeneous EIAs employing a probe complex enzyme--anti enzyme which competes with circulating ICs for the recognition unit (bovine conglutinin, C1q or monoclonal rheumatoid factor) to detect 10 unrelated in vitro-made ICs at different relative Ag/Ab concentrations (from 8 x Ag excess to 8 x Ab excess). We demonstrated that the 3 recognition units recognised the ICs principally on the basis of their Ag/Ab ratio. These results were then used to set up a mathematical model capable of retracing the Ag/Ab ratio of the ICs present in unknown samples. This was employed to test a panel of sera from patients with systemic lupus erythematosus, essential mixed cryoglobulinemia and rheumatoid arthritis; we obtained very suggestive results but they require further prospective studies to understand the full significance of this parameter.

Antibodies↗