Fluid entry mechanism for a modular automated diagnostic...

Measuring and testing – Sampler – sample handling – etc. – Capture device

Reexamination Certificate

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Reexamination Certificate

active

06418800

ABSTRACT:

FIELD OF THE INVENTION
The present invention is related to an automated diagnostic analyzer and, in particular, to an automated diagnostic analyzer capable of accepting biological samples from a variety of sample containers and providing automatic cleaning of the exterior and interior surfaces of the analyzer such that there is no contamination of the analyzer and with an improved internal fluidic system, an improved valve for introducing calibrants and air into the fluidic system, and a self contained reagent pack capable of storing and handling tonometered calibrants for blood gas determination.
BACKGROUND OF THE INVENTION
An important and frequently required diagnostic analysis, such as may be performed in clinical or laboratory medical practice, is the automated chemical analysis of biological samples, and in particular biological samples containing whole cells or cellular debris, such as whole blood, plasma or serum, or other biological fluids wherein the term fluid includes both liquids and gases. The analysis of biological samples containing cells or cellular debris saves valuable time in reaching a diagnosis and treatment by eliminating the separation step, which can be critical in an emergency situation, and reduces the cost of each analysis.
A major problem in the automated chemical analysis of samples containing whole cells or cellular debris, however, is the delivery of the samples from a sample container, such as a hypodermic tube, test tube or other sample container, and into the analysis apparatus. Biological samples, and in particular those containing cellular materials, have a tendency to leave films containing proteins and other biological molecules on the surfaces of the analysis apparatus. As a result, each of successive samples introduced into the analysis apparatus can simultaneously pick up constituents left on the surfaces from previous samples and deposit new constituents, so that a sample can be contaminated by one or more previous samples. This problem is particularly acute given the sizes of the samples customarily used in such analyzers, which are typically in the range of micro-liters.
These residual films tend to accumulate over time, so that the problem increases as the number of samples increases, and the interaction between a given sample and the residual films from previous samples in unpredictable, depending upon the constituents of the samples and the composition of the residual films.
Methods for dealing with this problem as regards the interior surfaces of an analysis apparatus have long been available and generally involve regular washing or flushing of the interior passages and chambers of the apparatus through which the biological samples pass. A typical analysis apparatus will normally use the pumps, tubing and passages used to move the samples through the device to also move the cleaning solutions through the device, thereby insuring that all internal surfaces, passages and chambers that come in contact with the samples also come in contact with the cleaning solutions. These cleaning solutions range from mild to aggressive, usually containing strong alkaline constituents, such as bleach, or enzymatically active constituents, such as proteases. For this reason, many automated analysis devices are provided with containers, either located within the apparatus or outside the apparatus itself, for storing cleaning solutions and the waste products resulting from cleaning operations.
These cleaning methods are confined to the interior surfaces of the analysis apparatus, that is, the surfaces of the passages and chambers through which the samples and reagents flow in passing from the sample entry point to the analysis sensors and the surfaces of the analysis sensors that are contacted by the samples. It will be noted, however, that the methods of the prior art for cleaning even the interior surfaces of an analysis apparatus are often inadequate to prevent interaction between a sample and the residue or residual films from previous samples and there is frequently contamination between samples and calibration reagents. In particular, the interior fluid paths of the analysis apparatus of the prior art frequently include “dead” spaces or voids that trap portions of the samples and fluids flowing therethrough and such “dead” spaces and voids are difficult to flush out or clean, so that the residues or films trapped in such areas may in turn contaminate subsequent samples. Such voids and “dead” spaces frequently occur, for example, in the corners of sharp bends in the fluid paths, in the corners formed where the fluid path changes dimensions and at sliding joints between sections of the fluid path. In addition, it is common in analysis apparatus of the prior art that the fluids pass through various moving parts in the path to the analysis sensors and such moving parts, such as sliding joints, valves and pumps, frequently contain voids and “dead” spaces that trap residues or residual films that may contaminate other fluids subsequently flowing through the apparatus.
Further, it is apparent that the samples also contact the exterior surfaces of the apparatus, in particular at or around the sample entry point where the samples first enter an analysis device, such as at the input to an aspirating probe through which the samples are drawn into the apparatus. Because these surfaces are not interior to the device, and are therefore not part of the cleaning solution path within the device, the films can build up on these surfaces in a relatively unhindered manner.
The buildup of films and deposits on the exterior surfaces of an analysis apparatus, for example, at the sample entry point such as an aspiration probe, have been usually handled in the prior art by having the user manually wipe the contaminated surfaces. This method, however, is unsatisfactory for many reasons. For example, not only does the manual cleaning of the apparatus impose an additional task on an already too busy user, but the user may forget to clean the sample entry as often as necessary, or at all, with resulting contamination of the samples. In addition, the user is undesirably exposed to biological hazards when manually cleaning the apparatus, such as puncture wounds from a contaminated aspiration probe and the sample residues themselves. The user must also safely dispose of the contaminated cleaning supplies, further adding to the cost and inconvenience of analyzing biological samples.
Another problem in the automated biological analysis apparatus of the prior art arises from the need to calibrate the analysis apparatus in order to validate the results of the sample analyses. In this regard, the cost of providing separate means for delivering the calibration samples, or calibrantes, and the samples to be analyzed into the apparatus can be unacceptable and, if the calibrante and analysis sample delivery paths are not substantially the same, the differences in the paths can introduce systematic errors in the analysis process as regards the calibrantes or the samples being analyzed, or both.
For these reasons, the means by which calibrantes are introduced to the analysis mechanism and sensors is generally the same as that used to introduce the samples to be analyzed and the calibrantes generally follow the same flow path as the samples. This, however, can result in cross-contamination between the calibrantes and the samples and this cross-contamination can be more critical than cross-contamination between samples. This problem is compounded where multiple calibrantes are necessary, as the means by which the calibrantes are introduced to the apparatus must include the capability of switching among the calibrantes without cross-contamination among the calibrantes or between the calibrantes and the samples to be analyzed. The problem is further compounded in that many current analyzers provide completely automatic calibration, so that the means by which the calibrantes are introduced are more complex while, at the same time, being less accessible for cleaning.
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