Laboratory costing system based on number and type of test: its association with the Welcan workload measurement system.

A laboratory costing system which recovers all costs against tests, rather than using both test and request charges, was developed. Methods of recovering costs of routine and emergency services, of capital investment in equipment, of instrument maintenance costs and of general hospital overheads were considered. The Welcan unit system of workload measurement was applied to a range of test procedures. Both the Welcan unit value and unit value adjusted fro calibration and quality control (Welcan based weighting) correlated only moderately with locally derived analytical time per test and correlated poorly with direct analytical cost per test. The correlation of direct analytical cost per test with total cost per test was much stronger than that of analytical time per test with direct analytical cost per test. The data suggest that neither Welcan unit values, Welcan based weightings, nor locally derived analytical time per test can truly reflect total resource consumption for the provision of a range of test procedures. This factor should be borne in mind when applying operational or performance indicators based on Welcan units.

"Delfia" and "Amerlite": two sensitive nonisotopic immunoassay systems for assay of thyrotropin compared.

We assessed the LKB "Delfia" (time-resolved dissociation-enhanced lanthanide fluoroimmunoassay) and the Amersham "Amerlite" (enhanced luminescent immunometry) assays of thyrotropin in serum. Both assays are sensitive (respective detection limits: 0.02 and 0.04 milli-int. unit/L) and have very good within- and between-batch precision over a wide range of thyrotropin concentrations. Results by the two methods correlate well (r = 0.992); the regression equation is: Amerlite = 0.915 Delfia - 0.33 milli-int. unit/L. The standard curve for the Delfia assay was linear, but that for the Amerlite assay showed some deviation from linearity below 0.5 milli-int. unit/L. Both assays have a negative bias in comparison with radiolabeled immunoradiometric assays, as judged by results for samples from the Quality Assurance Scheme. Both assays discriminate well between hyper-, hypo-, and euthyroid subjects, and results for thyrotropin for most patients with nonthyroidal illness were within the euthyroid reference interval. Both assays are convenient to perform and are based on systems that provide a viable alternative to radioimmunoassay.

Costing clinical biochemistry services as part of an operational management budgeting system.

The process of costing clinical biochemistry tests as a component of the commissioning of a unit management budgeting system based on an International Computers Limited (ICL) minicomputer system was examined. Methods of apportioning consumable and labour costs under direct and indirect cost headings and as test and request charges were investigated, and in this currently operational system it was found that 38% of consumable costs and 57% of labour costs were not a direct component of the routine analysis function. Means of assigning test costs to a given request source and the incorporation of such charges into clinical budget statements were looked at. A reduction in laboratory workload did not produce a comparable reduction in laboratory costs. For a theoretical reduction in workload of 20% only a 3.8% laboratory saving in recoverable costs could be expected.

Intact parathyroid hormone assay offers increased sensitivity over C-terminal assays in the study of parathyroid graft function.

Serum parathyroid hormone (PTH) levels in 6 patients who had received parathyroid tissue autografts were studied. Samples were taken from graft and non-graft arms both pre- and post-dialysis. Each sample was analysed using two PTH assays, one measuring C-terminal PTH and the other measuring the intact PTH molecule. For both pre- and post-dialysis samples an appreciably greater difference was seen between the graft and non-graft arms using the intact assay. A patient with suspected ectopic PTH production showed a very much reduced differential between the two sampling sites with both assays. We suggest that the intact PTH assay is of greater clinical utility in the localisation of ectopic glands and monitoring of graft function than the commonly used C-terminal assays.

Rapid measurement of creatine kinase activity in a coronary care unit using a portable benchtop reflectance photometer.

Rapid measurements of plasma creatine kinase activity using an inexpensive benchtop reflectance photometer (Ames Seralyzer) and disposable reagent strips were evaluated in the laboratory and coronary care unit. The system proved simple to use and capable of yielding rapid (four minutes per analysis), precise (coefficient of variation less than 9%), and accurate results (correlation with routine method 0.995) when used by medical staff. Creatine kinase values were available 6.5-102 hours earlier than routine laboratory data, depending on the time and day of sampling, thereby facilitating appropriate and economic patient management. This instrument might be used to supplement the routine enzyme service for selected admissions, resulting in greatly improved availability of results and hence contributing to the early discharge of patients from intensive care facilities.

Six methods for urinary protein compared.

Six assays for protein in urine were compared for linearity, ease of standardization, precision, comparability of assay values, technical ease of assay, and current cost. The assays investigated were three dye-binding techniques, a recent turbidimetric technique, the trichloroacetic acid--biuret reaction, and a tannic acid protein precipitation reaction with ferric chloride. All assays suffered from standardization problems, although the biuret method showed the best analytical recovery of albumin and gamma-globulin. The tannic acid/ferric chloride method is dependent on sample pH. The turbidimetric assay exhibited the greatest imprecision; i.e., CVs were 19.5% at a protein concentration of 0.13 g/L and 6.0% at a protein concentration of 1.3 g/L. On the basis of all the factors assessed, we conclude that the Pesce/Strande Ponceau-S and the Bio-Rad Coomassie Brilliant Blue dye-binding techniques offer certain advantages over the other assays studied.

Rapid automated ion-exchange analysis of plasma tyrosine and phenylalanine with data print-out.

A rapid automated method with data print-out is described for quantitation of plasma phenylalanine and tyrosine from 0.100 ml of sample. The system uses the Rank-Hilger Chromaspek amino acid analyser linked to a Digico M16E computer. Amino acid concentration up to 3000 microM can be quantitated without repeat dilutions and assessment of precision at the 500 microM level, produced coefficients of variation of 2.2% for tyrosine and 2.5% for phenylalanine. Recovery determinations from a plasma pool gave a mean recovery of 99.4% for tyrosine and 99.7% for phenylalanine. Correlation with established fluorimetric techniques was excellent (r = 0.986 for tyrosine, r = 0.976 for phenylalanine). By using the same resin column for both the rapid separation of tyrosine and phenylalanine, and the standard physiological fluid separation, full analysis capability is retained with easy interchange between the two systems.