Whole-blood test for total cholesterol by a self-metering, self-timing disposable device with built-in quality control.

A whole-blood test for total cholesterol has been developed that is performed in a low-cost disposable flow device without user intervention (after sample addition). The device meters the sample, separates plasma from erythrocytes, and precisely times plasma flow into various reagent compartments, including a quality-assurance chamber. Test results are displayed as a well-defined and easily readable color bar.

Novel reagent and method for direct determination of chloride in serum with a centrifugal analyzer.

We report a novel reagent containing ferric perchlorate, perchloric acid, and polyoxyethylene (23) lauryl ether (Brij 35) with which the concentration of chloride in serum can be measured. We applied this reagent to use with a centrifugal analyzer (CentrifiChem 400) in a dynamic bichromatic procedure, resulting in broad linearity of the standard curve (0-180 mmol/L), short analysis time (1 min), and little interference from bilirubin, hemoglobin, turbidity, or bromide ions. The reagent is simple, contains no mercury, and the combination of low acid concentration and surfactant prevents serum protein precipitation.

Optimized method for measuring aspartate aminotransferase activity with the CentrifiChem Analyzer, with automatic preincubation of serum.

We propose a routine method for the mechanized measurement of aspartate aminotransferase with the CentrifiChem Analyzer, which is based on the recommendations of both the International Federation of Clinical Chemistry and the Société Française de Biologie Clinique. A modification of the CentrifiChem pipettor permits simultaneous pipetting of two reagents, thus achieving automatic preincubation of the serum in the transfer disk. Owing to the fixed reagent volumes dispensed by the pipettor, preincubation conditions had to be modified, but the recommendations for the final reagent concentrations in the assay cuvet were observed.

Automated radioimmunoassay of choriomammotropin (human placental lactogen).

We describe a totally automated procedure for radioimmunoassay of choriomammotropin, in which all phases of the assay are automated in a single system ("Centria"). This system permits the simultaneous incubation and separation of many samples in a nonequilibrium assay, and measurements are obtained in less than 30 min. Results for clinical samples by reference radioimmunossay methodology and with the Centria system compared uniformly well: y=0.

Simplified, totally enzymatic method for determination of serum triglycerides with a centrifugal analyzer.

We describe a totally enzymatic method for determination of serum triglycerides (triacylglycerols) specifically adaptable to the CentrifiChem system. The method involves lipolysis with lipase from Rhizopus arrhizus alone and quantitation of the resulting glycerol with glycerol dehydrogenase in a kinetic, fixed-time mode. Hydrolysis by the lipase is complete, for concentrations up to at least 5.