Practical considerations for the measurement of free light chains in serum

Background: A new immunoassay for free light chain measurements has been reported to be useful for the diagnosis and monitoring of monoclonal light chain diseases and nonsecretory myeloma. We describe experience with and some potential pitfalls of the assay. Methods: The assay was assessed for precision, sample type and stability, recovery, and harmonization of results between two analyzers on which the reagents are used. Free-light-chain concentrations were measured in healthy individuals (to determine biological variation), patients with monoclonal gammopathy of undetermined significance, myeloma patients after autologous stem cell transplants, and patients with renal disease. Results: Analytical imprecision (CV) was 6-11% for kappa and A free-light-chain measurement and 16% for the calculated kappa/lambda ratio. Biological variation was generally insignificant compared with analytical variation. Despite the same reagent source, values were not completely harmonized between assay systems and may produce discordant free-light-chain ratios. In some patients with clinically stable myeloma, or post transplantation, or with monoclonal gammopathy of undetermined significance, free-light-chain concentration and ratio were within the population reference interval despite the presence of monoclonal intact immunoglobulin in serum. In other patients with monoclonal gammopathy of undetermined significance, values were abnormal although there was no clinical evidence of progression to multiple myeloma. Conclusions: The use of free-light-chain measurements alone cannot differentiate some groups of patients with monoclonal gammopathy from healthy individuals. As with the introduction of any new test, it is essential that more scientific data about use of this assay in different subject groups are available so that results can be interpreted with clinical certainty. (C) 2003 American Association for Clinical Chemistry.

A framework for progressively improving small area population estimates

The paper presents a framework for small area population estimation that enables users to select a method that is fit for the purpose. The adjustments to input data that are needed before use are outlined, with emphasis on developing consistent time series of inputs. We show how geographical harmonization of small areas, which is crucial to comparisons over time, can be achieved. For two study regions, the East of England and Yorkshire and the Humber, the differences in output and consequences of adopting different methods are illustrated. The paper concludes with a discussion of how data, on stream since 1998, might be included in future small area estimates.

Outcome measurement in Australian rehabilitation environments

Objective: To determine the frequency and pattern of methods of outcome assessment used in Australian physical rehabilitation environments. Design: Postal survey. Methods: A questionnaire on service type, staffing, numbers of adults treated and outcome measures used for 7 conditions related to injury and road trauma as well as stroke and neuromuscular disorders was sent to 973 services providing adult physical rehabilitation treatment. Results: Questionnaires were completed by 440 service providers for a response rate of 45%, similar to that reported in a recent European survey reported in this journal. A small number of measures were reported as in use by most respondents, while a large number of measures were used by a few respondents. Measures of physical changes were used more frequently than those of generic well-being or quality of life. Ease of use and reporting to other professionals were cited as the most important reasons in selection of outcome measures. Conclusion: This Australian-wide survey detected considerable heterogeneity in outcome measurement procedures used in rehabilitation environments. While the goal of measurement may vary between providers and differ between conditions, the results highlight opportunities for harmonization, benchmarking and measurement of health-related quality of life.

Formal considerations of rule-based messaging for Business Process Integration

In the last decade, with the expansion of organizational scope and the tendency for outsourcing, there has been an increasing need for Business Process Integration (BPI), understood as the sharing of data and applications among business processes. The research efforts and development paths in BPI pursued by many academic groups and system vendors, targeting heterogeneous system integration, continue to face several conceptual and technological challenges. This article begins with a brief review of major approaches and emerging standards to address BPI. Further, we introduce a rule-driven messaging approach to BPI, which is based on the harmonization of messages in order to compose a new, often cross-organizational process. We will then introduce the design of a temporal first order language (Harmonized Messaging Calculus) that provides the formal foundation for general rules governing the business process execution. Definitions of the language terms, formulae, safety, and expressiveness are introduced and considered in detail.