Abstract: Binding assays are effected by introducing a specific binding reagent through a top absorbant membrane in parallel contact with a main absorbant membrane. By providing a parallel flow of liquid in the two membranes, and by controlling the flow of the diluted reagent from the top absorbant membrane into the main absorbant membrane, a controlled, uniform dilution of the reagent is obtained, leading to more accurate assay results.

Abstract: An analyzer automatically performs analytical operations in which liquid samples for analysis and required reagents are held in suitable vessels. To increase the number of vessels which can be received in the analyzer and to simplify the device for reading the bar code labels, the analyzer contains at least two vessel holders, a bar code reader, and means for automatically adjusting the focal range and the bar code reader. The vessel holders are disposed parallel to one another in the analyzer. A number of vessels of the same kind (for example, sample-containing vessels) are disposed in each vessel holder. Each vessel holder has an elongate body manufactured in one piece and contains a single straight row of identical elongate chambers for receiving one vessel. All chambers have a common base and are disposed perpendicularly thereto. Adjacent chambers are separated by a partition.