Computerized threshold determination for automated ABO/Rh tests.

Automated microplate blood-grouping systems rely on a pair of thresholds to determine whether reactions are positive or negative. The determination of these thresholds is a critical step in the quality control process for automated microplate blood grouping. A simple method has been developed for automatically setting these thresholds. A more sophisticated method, which required substantial computational complexity, was also tried. The more complex method did not perform better than the simple method described here.

A one-step Du test in microplates.

A one-step Du test, developed for use in automated microplate systems, uses anti-D with 0.6 percent dextran to potentiate the reaction. Because the washing and reagent-adding steps of the antiglobulin test are not required, the Du test can be performed in the same microplate as the ABO/Rh test. A set of reactions prepared with this technique was visually interpreted and also classified by an automated microplate ABO/Rh system. Visual interpretation of reactions resulted in a sensitivity and specificity close to those of the antiglobulin test, although the sensitivity of the test was reagent-dependent. When the automated microplate blood grouping system was used, the test was not as sensitive or as specific as the antiglobulin test, although it may be sufficient for many applications.

Considerations in the use of laboratory robots: aspects of safety and accuracy.

A general-purpose laboratory robot was configured to prepare blood samples for the HBsAg and anti-HIV tests. Several issues were studied in order to eliminate problems and optimize the system. These included pipetting accuracy, intersample carryover, reagent interference, splashing and aerosol generation and user-related issues. A number of general guidelines were developed to assist others in developing and implementing systems for this and similar applications.