Clinical relevance of CD157 for rapid and cost-effective simultaneous evaluation of PNH granulocytes and monocytes by flow cytometry.

INTRODUCTION: CD157 has been reported as a potentially useful marker for paroxysmal nocturnal hemoglobinuria (PNH) testing by flow cytometry (FCM). METHODS: We determined the performance characteristics of a CD157-based five-color assay and compared results from patient analysis with results obtained with a previously validated CD14/CD24-based six-color protocol. RESULTS: Coefficient of variation (CV) for intra-/interassay precision analysis of granulocytes ranged from 0.88/0.09% to 3.02/3.71% and from 0.20/0.08% to 8.83/4.04% for the five- and six-color protocol, respectively. For monocyte, CV ranged from 0.42/0.49% to 8.13/4.80% for the five-color protocol and from 0.28/0.70% to 5.41/3.19% for the six-color protocol within various PNH clones. Coefficient of determination (r(2) ) for linear regression analysis of PNH clones ranging from 0.3 to 99.8% was >0.99 in all cases, Wilcoxon ranks test showed no statistically significant differences (P > 0.05), and Bland-Altman analysis demonstrated agreement with mean bias ranging from -0.02 to 0.38. CONCLUSION: Our results confirm very good performance characteristics for both intra- and interassay precision analyses, excellent correlation, and agreement between approaches. In agreement with recently published data, our experience supports the clinical relevance of CD157 for a rapid and cost-effective simultaneous evaluation of PNH leukocytes by flow cytometry.

Interlaboratory variability of CD34+ stem cell enumeration. A pilot study to national external quality assessment within the Czech Republic.

We present the results of a pilot study concerning the interlaboratory variability of CD34+ enumeration. Three surveys, each including a set of samples, were sent to participating Czech flow cytometry laboratories. The efficacy of this exercise was determined by the reduction in interlaboratory variation and the influence of method used on assay outcome. The variability in results of CD34+ enumeration declined with time. The mean coefficient of variation (CV) of measurement among laboratories dropped, from 58% in first survey to 32% in last survey. All tested variables (gating strategy, platform methodology, sample preparation) affected the variability of the assay. Sample preparation method was associated with a significant bias of absolute CD34+ cell counts. Initially, the outcome of the measurement was also affected by the participating laboratory (identified by a unique laboratory number; ULN). However, laboratories with poorer performance modified their protocols during the study, and the ULN ceased to influence the variability. This study was successful in reducing the interinstitutional variability of CD34+ enumeration. It was shown that the implementation of a standardized protocol does not guarantee accurate measurement. Our research design represents a useful tool, which allows verification of the proper use of a standardized method, the training of operators and feedback in response to the survey results.

[Issues of migration and the standard of living in Strandzha-Sakar (using the example of the Malko Turnovo administrative region)]. / Problemi na migratsiyata i zhiznenoto ravnishche v Strandzha-Sakar (na primera na Malkot'rnovskata selishchna sistema).

PIP: These are the results of a study on the relationship between living standards and migration in the Malko Turnovo administrative region of Bulgaria. The focus is on the need to develop the local infrastructure to attract settlers from other areas and the need to develop good relations between current residents and new in-migrants. (SUMMARY IN ENG AND RUS)^ieng