Abstract: The invention is a method for detecting failures in an analyzer for conducting clinical assays. Potential errors that can result in assay failures in an analyzer are identified, as are their potential sources. The probability that an error source so identified will result in a clinically significant error is also determined. Available potential detection measures corresponding to the source of potential errors are identified with a combination of such measures selected and implemented based on their probability of detecting such errors within an acceptable limit with a concomitant low probability of the false detection of an assay failure. Each of the measures selected are functionally independent of others chosen to address the source of the error and are not subject to the same inherent means of failed detection. Applications of the method in a clinical analyzer are also presented.

Abstract: A method of preventing false detection of signal due to splashing of reagent liquid used to produce such signal, when dispensing at least one such liquid from a metering tip into a second liquid, comprising the steps of: a) positioning the metering tip a predetermined distance above the upper level of the second liquid prior to dispensing the one liquid; andb) while maintaining the distance throughout the dispensing of the one liquid, dispensing the one liquid;wherein the predetermined distance is between about 1.0 mm and about 2.0 mm so that splashing during dispensing is reduced.

Abstract: Method and apparatus for determining actual liquid volumes in vessels in an incubator rotor that experiences vertical run-out as it rotates past stations that fill the vessels with liquid. Air pressure is used to determine the height of the bottom of each of the empty vessels, and then the height of the liquid that fills the vessels, so that the difference in height is converted into volume to compare with the desired and expected volume for the operation that does the volume-filling.

Abstract: A method for determining and correcting for the variations in height of a rotor as it wobbles when rotating past a particular critical circumferential position. The method comprises sensing a reference surface of each vessel in the rotor that is to be filled during the use of the rotor in an incubator, as a tare height of the vessel, so that the effect of the vertical run-out is known and corrected for by the computer. Air pressure is used to detect the reference surface, either from a vessel-wash probe connected to the source of air pressure, or a separate sensor probe.