The Performance of the 'Centrifichem' Parallel Fast Analyser Using Packaged Reagents

use. The creatinine kit contained seven bottles of reagent 1 and seven bottles of reagent 2, with instructions to mix equal quantities of 1 and 2. 6 mI of each are needed for one transfer disc. All the other kits contained 12 bottles of dry reagents, together with one larger bottle of buffer solution, with instructions to add 10 ml of this to each bottle as required and shake gently until dissolved. When suitably mixed for use the stated concentrations of the various reagents were as follows (the enzyme kits fulfilled the recommendations of the German Society for Clinical Chemistry (1972»: The CentrifiChem parallel fast analyser consists of a rotor containing 30 cuvets, a tungsten-iodide light source, a monochromator (interference filters), a photomultiplier tube detector, and a printer which gives the results in 4 digits. Samples and reagents are separately metered into a transfer disc by the pipettor unit. The disc is transferred to the rotor. and on rotation the fluids are simultaneously moved from the disc into the corresponding cuvets on the rotor. Sample and reagent are further mixed by drawing air through siphons connected to the cuvets. Transmittance of the samples is measured as the stationary light beam scans all the cuvets during rotation, hence generating a continuous series of pulses corresponding sequentially to the light transmitted by each cuvet. Transmittance is con­ verted to absorbance by a logarithmic amplifier and then, via an analog to digital converter, to the computer processor. On completion of the run the necessary calculations are performed and printout of the results is initiated. In addition, an oscilloscope display gives a visible monitor of all the reaction cuvets simultaneously. This display provides a means of detecting discrepancies due to exhausted substrate because of high activity. At the end of the series of readings the cuvets are emptied automatically through the siphons, and the assembly can be rinsed with water any number of times. After bringing the rotor to rest and removing the transfer disc. the cuvets can soon be dried ready for the next analysis by rinsing with a little ethanol and then drawing air through the assembly. Alanine aminotransferase (ALT) L-alanine cx-oxoglutarate lactate dehydrogenase (LD)