Impact of uncontrolled freezing and long-term storage of peripheral blood stem cells at - 80 °C on haematopoietic recovery after autologous transplantation. Report from two centres.

Controlled-rate freezing and storage in vapour phase nitrogen are used by most transplantation teams for the cryopreservation and storage of peripheral blood haematopoietic stem cells (PBSC). In this study, we analysed 666 autologous PBSC transplants after uncontrolled freezing and storage of PBSC at -80 °C. Statistical analysis showed that neutrophil recovery was associated with both the infused CD34(+) cell dose (P=0.01) and the post transplantation use of growth factors (P<0.001) and that platelet recovery was associated with the infused CD34(+) cell dose (P<0.001) and with the diagnosis (P=0.02). We analysed three groups according to the duration of the cryopreservation period (less than 6 months, between 6 and 12 months or more than 1 year). Haematopoietic recovery was not found to be adversely affected by longer storage at -80 °C. The haematopoietic recoveries of 50 pairs of sequential transplantations from the same PBSC mobilization were analysed. Despite prolonged cryopreservation, there were no statistically significant differences in neutrophil (P=0.09) or platelet (P=0.22) recovery in the second compared with the first transplant. In conclusion, the long-term storage of PBSC at -80 °C after uncontrolled-rate freezing is an easy and comparatively inexpensive cryopreservation method that leads to successful haematopoietic recovery even after prolonged storage.

Evaluation of a second-generation thyrotropin automated immunoassay.

We evaluated the analytical performance of the Vista automated immunoassay system for human thyrotropin determination. The operating characteristics as well as the analytical performance were assessed. The Vista human thyrotropin immunoassay showed a minimal detection limit of 0.08 mU/l and a functional sensitivity of 0.12 mU/l. The system meets the criteria for second-generation human thyrotropin assays.

Utilization of laboratory resources: developments in knowledge-based ordering systems.

This paper describes two rule based decision support systems. The first system is used to screen incoming test requests for adequacy on the basis of signs and symptoms volunteered by the requesting GPs. The system was tested using a database of 794 requests for a TSH test. About 17% of the test requests were correctly identified as unnecessary. In total, 0.5% of the tests were incorrectly labelled as unnecessary. This concerned 4% of the patients that appeared to have hyperthyroidism and 23% of the patients that appeared to have hypothyroidism on the basis of TSH and FT4 results. The other system is a rule-based clinical decision support system for the requesting of laboratory investigations, originally designed for use at a hospital within the UK, that was implemented in a predominantly French-speaking hospital in Belgium. This involved the modification of the system to allow multilingual operation, and also the implementation of a completely new set of investigation protocols. The purpose of this study was to assess the transferability, both of the system itself, and of its benefits. The system was introduced gradually and has only recently been in full operation. However, the findings from the first months of routine use of the system indicate that the transfer of the system to a different clinical environment has been successful. Although it is too early to assess fully the impact on laboratory utilization, the clinicians believe that it is improving the appropriateness of investigations.

A rule-based decision support application for laboratory investigations management.

The appropriate management of clinical laboratory requests in specialised clinical units often requires the adherence to pre-defined protocols. We evaluated the impact of a rule-based expert system for clinical laboratory investigations management in a pediatric liver transplantation unit of our hospital. After one year, we observed an overall reduction in laboratory resources consumption for transplanted patients (-27%) and a decrease in the percentage of "STAT" requested tests (-44%). The percentage of tests ordered in agreement with the protocols for those patients increased from 33% before the introduction of the expert system to 45% when the system was used. The system was perceived by the clinicians as increasing the overall benefits in use of clinical resources, improving the laboratory data management, and saving time for the execution of laboratory ancillary tasks.