Electronic timing of a high-speed immunonephelometric continuous-flow system.

We describe a high-speed immunoephelometric continuous-flow system. The mechanical timing asembly and cams of the sampler were replaced by an external electronic control unit. Improved sampling precision, speeds of 2 to 900 samples per hour, and a wide variety of sample-to-wash ratios are the most important advantages of the unit. We analyzed albumin and fibrinogen at speeds of 150, 180, and 210 samples per hour. Carry-over studies showed that, in clinical practice, it should be possible to run the system at 150 samples per hour with an interaction of less than 5% and a precision (CV) of around 4%. Comparative studies with a previously described method, run at 60 samples per hour, showed correlation coefficients of 0.968 and 0.935 for albumin and fibrinogen, respectively. The electronic control unit can be used to increase speed and improve sampling precision of any continuous-flow system. An immunonephelometric system equipped with this device provided fast and reliable results, and required less antiserum than other systems described.