Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Means for analyzing liquid or solid sample
Patent
1992-10-06
1994-03-29
Warden, Robert J.
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Means for analyzing liquid or solid sample
422 8205, 422 8207, 356 39, 356440, 73 6443, 128DIG22, G01N 2100, G01N 3348
Patent
active
052982246
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to an apparatus for the measuring of a blood sample, and comprising transparent capillary elements for taking up the blood, and a housing-mounted photometer with measuring cells for the optical detection of the light permeability of the sample in the capillary element, and which is connected to a computer for the determination of the coagulation time of the sample.
BACKGROUND OF THE INVENTION
Apparatus of this kind is used particularly by haemophilia patients for measuring the coagulability of the blood, and hereby for the determination of whether there is need for the injection of a factor VIII preparation in order to avoid haemorrhages.
Equipment of this kind is known from EP publication no. 120 715. Here, the capillary element consists of a measuring cell in the form of an elongated channel at the end of a holder. Blood is sucked up into the channel, and the measuring cell can hereafter be inserted into a measuring apparatus with a light source and a photometer. The photometer measures the amount of light which, after the emission, passes the transparent side of the measuring cell, and which after reflection in the blood and the back of the measuring cell again passes through the transparent side.
This measuring cell does not, however, provide an accurate measurement result, the reason being that it is based on reflection. This gives rise to a measurement inaccuracy which is so great that it is unsuitable for the measurement of the coagulability of the blood. Furthermore, it is difficult to produce such a measuring cell, the reason being that the capillary element is built up of at least two parts which must be assembled for the formation of an element.
From the Swedish publication no. 404 260, an apparatus is known which can measure with greater accuracy, since this uses a beam of light and light detecting elements which are placed at an angle in relation to the light's direction of incidence in the sample.
However, this apparatus demands a precisely balanced positioning of these measuring means in relation to the blood sample, and in practice this means that the blood must be kept in a vessel-like container during the measurement. Since at a minimum there must be sufficient blood to cover the light detectors, a considerable amount of blood is required. This is a serious drawback for the user, the reason being that such a large amount of blood in practice can be obtained only with the help of a suction pump and hypodermic. Therefore, this apparatus is not suitable for so-called home use, where the user himself must be able to remove the blood sample necessary for a measurement.
SUMMARY OF THE INVENTION
It is the object of the invention to remedy these deficiencies and disadvantages of the known kinds of apparatus, and this is achieved by means of an apparatus where each capillary element constitutes a glass or a plastic tube, the inside diameter of which is less than 0.5 mm.
The accuracy of measurement achieved hereby is considerably increased, since one can transilluminate the blood in the tube transversely to said tube. This reduces the measurement inaccuracy, the reason being that the tube can be produced with precise dimensions and of a homogenous material. This makes it well-suited for use in the measurement of the coagulability of the blood.
Furthermore, for reasons of the small internal diameter of the tube, a considerably smaller amount of blood is required in relation to the known types of measuring apparatus. For the filling of a tube length of, for example, 30 mm, less than 1 microliter liter is required. In practice, a drop of blood procured by, for example, the pricking of a finger, could fill several tubes, which provides the possibility of filling, for example, a prepared and an unprepared tube from one and the same drop of blood.
The apparatus thus becomes convenient to use, in that it is simple and quick to remove and take up a drop of blood in the tubes for use in the measurement.
By mounting the tubes on an independent support eleme
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Novo Nordisk A S
Trembley T. A.
Warden Robert J.
Zelson Steve T.
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