Liquid purification or separation – Filter – Vacuumized filtrate receiver
Reexamination Certificate
1999-04-07
2001-04-24
Barry, Chester T. (Department: 1724)
Liquid purification or separation
Filter
Vacuumized filtrate receiver
C210S416100, C210S455000, C210S473000, C210S489000, C210S456000
Reexamination Certificate
active
06220453
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a blood filter unit for the preparation of a plasma or serum sample from whole blood, and a plasma- or serum-collecting device using it.
The type or concentration of blood components, such as metabolites, proteins, lipids, electrolytes, enzymes, antigens, and antibodies, is measured, in general, using a plasma or serum sample obtained by centrifuging whole blood. However, centrifuging takes labor and time. Particularly, centrifuging is unsuitable for an urgent case of measuring a small number of samples promptly and in site inspection, because of requiring a centrifuge and electricity. Thereupon, it has been investigated to separate serum from whole blood by filtration.
Several filtration methods using glass fiber filter have been developed wherein whole blood is charged into the glass fiber put in a column from one side of the column, and pressurized or evacuated to obtain plasma or serum from the other side (Japanese Patent KOKOKU Nos. 44-14673, 5-52463, Japanese Patent KOKAI Nos. 2-208565, 4-208856).
However, practical filtration methods capable of obtaining an amount of plasma or serum from whole blood necessary for measuring by an automatic analyzer have not been developed except a part of items, such as blood sugar.
On the other hand, the inventors developed a blood filter unit composed of a filter holder and a syringe. The filter holder is composed of a holder body which contains filter material and a cap which is screwed on the holder body. The filter material consists of, e.g. two sheets of glass fiber filter, one sheet of cellulose filter and one sheet of polysulfone microporous membrane (
FIG. 1
of EP 785430 A1)
Another blood filter unit composed of a holder body and a cap was also developed. The holder body consists of a plasma receiver located on the upper side and a filter chamber located on the underside. The filter material put in the filter chamber is composed of six sheets of glass fiber filter and one sheet of polysulfone microporous membrane (Example 1 of EP 785012A1).
These blood filter units have a problem in handling. That is, drawn blood is put in a blood collecting tube, and transported. Upon conducting blood analysis, a cap of the blood collecting tube is taken off, and a suction nozzle of the blood filter unit is inserted into the blood collecting tube. However, this manner adds load to workers in assay laboratories where a lot of blood samples are analyzed. Moreover, a suction apparatus is necessary for suction filtration of blood using the blood filter unit, and accordingly, the place conducting blood filtration is restricted.
It is also a problem that agglutinates of blood cells gradually deposited clog the suction nozzle during filtering blood.
SUMMARY OF THE INVENTION
An object of the invention is to provide a blood filter unit and a plasma- or serum-collecting device capable of obtaining a necessary volume of a plasma or serum sample from blood to be assayed easily at any place.
Another object of the invention is to provide a blood filter unit and a plasma- or serum-collecting device capable of continuing blood filtration without clogging the suction nozzle.
As a result of investigating eagerly, the inventors devised a blood filter unit comprising a blood filtering material and a holder accommodating the blood filtering material and having a nozzle for sucking blood and a filtrate outlet, and the inside of the holder being kept reduced pressure conditions which has achieved the above object.
The inventors also devised a blood filter unit comprising a blood filtering material and a holder accommodating the blood filtering material and having a nozzle for sucking blood and a filtrate outlet, and the inside of the holder being kept reduced pressure conditions, wherein the container has a space capable of containing the drawn blood without the end opening of the suction nozzle and the filtrate outlet in the blood, can be turned to dip the end of the suction nozzle in the drawn blood without spilling the blood.
The inventors further devised a blood filter unit comprising a blood filtering material and a holder accommodating the blood filtering material and having a nozzle for sucking blood and a filtrate outlet, and the inside of the holder being kept reduced pressure conditions, wherein the container is provided with an agglutinate checking member which restricts the movement of the agglutinate of blood cells.
REFERENCES:
patent: 3800947 (1974-04-01), Smith
patent: 4202769 (1980-05-01), Greenspan
patent: 4898572 (1990-02-01), Sugugue Nee Lasnier
patent: 5868928 (1999-02-01), Bradley
patent: 5979669 (1999-11-01), Kitajima et al.
patent: 5996811 (1999-12-01), Kitajima et al.
Kitajima Masao
Tezuka Sigeru
Washizawa Yasuo
Yazawa Kenichiro
Barry Chester T.
Fuji Photo Film Co. , Ltd.
Reed Smith LLP
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