Biomedical subjects

S L Braun

Publications and source records attributed to S L Braun.

24 records · Page 2Linked to original sources

PubMed1994

Realistic modeling of clinical laboratory operation by computer simulation.

An important objective of laboratory management is to adjust the laboratory's capability to the needs of patients' care as well as economy. The consequences of management may be changes in laboratory organization, equipment, or personnel planning. At present only one's individual experience can be used for making such decisions. We have investigated whether the techniques of operations research could be transferred to a clinical laboratory and whether an adequate simulation model of the laboratory could be realized. First we listed and documented the system design and the process flow for each single laboratory request. These input data were linked by the simulation model (programming language SIMSCRIPT II.5). The output data (turnaround times, utilization rates, and analysis of queue length) were validated by comparison with the current performance data obtained by tracking specimen flow. Congruence of the data was excellent (within +/- 4%). In planning experiments we could study the consequences of changes in order entry, staffing, and equipment on turnaround times, utilization, and queue lengths. We conclude that simulation can be a valuable tool for better management decisions.

Chemistry, Clinical↗

PubMed1992

[Observations on the cost effectiveness of various methods of electrolyte determination].

New analytical methods have to be considered also with respect to their economic efficiency. Here we present the application of an economic analysis based on the rules of applied economics in our institute for clinical chemistry and laboratory medicine. We started with an analysis of laboratory structure and economic efficiency in 1988, which since then has been followed by a continuously performed laboratory controlling system. The results of unit costing show the different cost groups, which add up to the cost of a single electrolyte determination. Regarding the transferability of our data to other laboratories, one has to consider that the main cost groups besides personnel cost are the apportionment of the overhead cost and the depreciation cost; both may vary markedly between each laboratory. Variable cost (reagents and consumables) differ widely from flame photometry to enzymatic electrolyte determination, but they amount only to 3-15% of the total cost.

Blood Chemical Analysis↗

PubMed1990

Demonstration of a combined deficiency of xanthine oxidase and aldehyde oxidase in xanthinuric patients not forming oxipurinol.

Genetic heterogeneity has been suggested in xanthinuria from the hitherto unexplained ability of some patients with this hereditary disorder to convert allopurinol to its active metabolite oxipurinol--an activity generally attributed to xanthine oxidase. This study provides evidence that the enzyme aldehyde oxidase is also deficient in xanthinuric patients not converting allopurinol to oxipurinol, whereas a xanthinuric patient with normal formation of oxipurinol had normal aldehyde oxidase activity. It is concluded that the enzyme aldehyde oxidase is the principal enzyme responsible for the formation of oxipurinol in man.

Adult↗

PubMed1981

Cluster-oriented discriminant analysis; taxonomic classification of the thyroid function.

A computer assisted procedure for the diagnosis of thyroid diseases, based on seven clinical chemical parameters, is proposed. The population studied consisted of 592 consecutive outpatients with a tentative diagnosis of thyroid disease. Thyroxine, triiodothyronine, T3 uptake test, TSH before and after TRH application, its difference and thyroxine binding globulin have been determined. The patients were clinically examined and in each case a Tc-scintigram was obtained. As a first step, 20 biochemical patterns were defined by cluster analysis (pattern cognition). T check how good in grouping process was, linear discriminant analysis was applied after which the reclassification rates were very satisfactory. The clusters found corresponded well to the pathophysiological situations with some exceptions. As a second step, patients were assigned to these patterns by use of the derived discriminant functions (pattern recognition). The proposed method seems to have some advantages over other diagnostic models published hitherto.

Alpha-Globulins↗

PubMed1981

Evaluation of a new valproic acid enzyme immunoassay and comparison with a capillary gas-chromatographic method.

A new homogeneous immunoassay (EMIT) for valproic acid was evaluated. Besides testing the manual version of this enzyme immunoassay, we also developed two mechanized procedures for centrifugal analyzers (the CentrifiChem and the COBAS system), which take less time and are more precise than the manual method. Within-assay precision (CV) was 4.5% with the manual technique and 2% with the analyzers. Between-assay precision (CV) ranged from 4 to 13% for all three techniques. Accuracy of th manual method was checked by dilution and analytical recovery experiments. Our comparison of the EMIT results with those obtained by a comparison method (capillary gas chromatography) showed no significant difference. No interference from hemolysis, hyperbilirubinemia, or aliphatic amino acids was observed. At high concentrations of bile acids and with lipemic sera the analytical recovery rates decreased slightly, to 87% and 92%, respectively.

Amino Acids↗

PubMed1981

[Determination of triiodothyronine in serum with a heterologous enzyme immunoassay: results of a group survey].

This paper summarises the results of the evaluation of a heterologous enzyme immunoassay in antibody coated tubes for the determination of triiodothyronine (T3) by a group of 11 laboratories. The assay procedure is analogous to an established heterologous thyroxine enzyme immunoassay. The evaluation demonstrated that 1. the specificity of the assay and its analytical range between 0.46 and 9.2 nmol/l meet diagnostic requirements, 2. the intra- and interassay precision was in accordance with that commonly found in radio immunoassays, 3. the recovery of added T3 was between 90 and 103%, 4. the results agreed well with those of self-established radio immunoassays and were comparable with commercial RIA kits, 5. there was no interference by hyperbilirubinaemia or by high concentrations of bile acids, but interference can occur in very haemolytic and lipaemic samples. The great advantage of T3 enzyme immunoassays lies in the absence of restrictions and any authorization needed for working with radioactive substances.

Evaluation Studies as Topic↗